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Gutunganya aside adipike (ibanziriza nylon 66) iva muri peteroli ya CA (uruvange rwa cyclohexanone na cyclohexanol) ni ingamba irambye ishobora gusimbura uburyo gakondo busaba imimerere igoye. Ariko, ubucucike buke bw'umuyoboro w'amashanyarazi n'imihindagurikire y'umwuka wa ogisijeni bigabanya cyane ikoreshwa ryayo mu nganda. Muri uyu murimo, twahinduye hydroxide ebyiri za nickel hamwe na vanadium kugira ngo twongere ubucucike bw'umuyoboro w'amashanyarazi kandi tugumane imikorere myiza ya faradaic (>80%) mu buryo bunini bw'ubushobozi (1.5–1.9 V ugereranije na electrode ya hydrogen isubira inyuma). Inyigo z'igerageza n'iz'inyigisho zagaragaje inshingano ebyiri z'ingenzi zo guhindura V, harimo kwihutisha kubaka catalyst no kunoza uburyo cyclohexanone ishyirwamo. Nk'igihamya cy'igitekerezo, twubatse ihuriro rya membrane-electrode ryatanze aside adipike ifite imikorere myiza ya faradaic (82%) n'umusaruro (1536 μmol cm-2 h-1) ku bucucike bw'umuyoboro w'amashanyarazi bujyanye n'inganda (300 mA cm-2), mu gihe tugera ku butuze > amasaha 50. Uyu murimo ugaragaza ko ari wo musaruro mwiza mu gukora aside adipe, ufite umusaruro mwinshi n'ubushobozi bwo gukora inganda.
Aside Adipic (AA) ni imwe muri aside dicarboxylic z’ingenzi cyane kandi ikoreshwa cyane cyane mu gukora nylon 66 n’izindi polyamides cyangwa polymers1. Mu nganda, AA ikorwa binyuze mu gukaraba uruvange rwa cyclohexanol na cyclohexanone (ni ukuvuga amavuta ya AA) hakoreshejwe aside nitrique 50–60 vol% nk'umuti ugabanya ubushyuhe. Iyi nzira ifite impungenge ku bidukikije zijyanye no koherezwa kwa aside nitrique na oxides azote (N2O na NOx) nk'ibyuka bihumanya ikirere2,3. Nubwo H2O2 ishobora gukoreshwa nk'umuti ugabanya ubushyuhe bw'icyatsi kibisi, ihenze cyane kandi igoye kuyikora bituma bigorana kuyikoresha mu buryo bufatika, kandi hakenewe uburyo buhendutse kandi burambye4,5,6.
Mu myaka icumi ishize, uburyo bwo gukora imiti n’ibikomoka kuri lisansi hakoreshejwe amashanyarazi byakuruye ibitekerezo by’abahanga kubera ibyiza byo gukoresha ingufu zishobora kuvugururwa no gukora mu bihe byoroheje (urugero: ubushyuhe bw’icyumba n’umuvuduko w’ikirere)7,8,9,10. Muri urwo rwego, iterambere ryo guhindura amavuta ya KA muri AA ni ingenzi cyane kugira ngo haboneke ibyiza byavuzwe haruguru ndetse no gukuraho ikoreshwa rya aside nitrike na okiside nitrous ihumanya iboneka mu musaruro usanzwe (Ishusho ya 1a). Petrosyan n’abandi bakoze imirimo yo gutangiza ibikorwa byakozwe na Petrosyan n’abandi, bavuze ko cyclohexanone (COR; cyclohexanone cyangwa cyclohexanol byakunze kwigwa nk’ibigaragaza amavuta ya KA) kuri nickel oxyhydroxide (NiOOH), ariko ubucucike buke (6 mA cm-2) n’umusaruro uciriritse wa AA byabonetse11,12. Kuva icyo gihe, hari intambwe ikomeye yatewe mu iterambere rya catalysts zishingiye kuri nickel kugira ngo hongerwe imikorere ya COR. Urugero, katalyst ya nickel hydroxide (Cu-Ni(OH)2) yakozwe mu rwego rwo guteza imbere ukwangirika kwa Cα-Cβ muri cyclohexanol13. Duherutse gutangaza ko katalyst ya Ni(OH)2 yahinduwe na sodium dodecyl sulfonate (SDS) kugira ngo ikore ibidukikije bito bito bitera hydrophobic cyclohexanone14.
a Imbogamizi zo gukora AA binyuze mu gukwirakwiza amavuta ya KA mu buryo bwa electrooxidation. b Kugereranya COR ya electrocatalytic ya catalysts zishingiye kuri Ni zavuzwe mbere hamwe na catalysts zacu muri sisitemu ya electrode eshatu na sisitemu ya bateri igenda11,13,14,16,26. Amakuru arambuye ku bipimo by'imyanzuro n'imikorere y'imyanzuro aratangwa mu mbonerahamwe y'inyongera ya 1 na 2. c Imikorere ya catalytic ya catalysts zacu za NiV-LDH-NS kuri COR muri reactor ya H-cell na MEA, zikora ku rugero runini rw'ubushobozi.
Nubwo uburyo bwavuzwe haruguru bwazamuye imikorere ya COR, catalysts zishingiye kuri Ni zagaragaje ubushobozi bwo hejuru bwa AA Faraday (FE) (>80%) gusa ku bushobozi buri hasi, ubusanzwe buri munsi ya 1.6 V ugereranije na electrode ya hydrogen ivugururwa (RHE, mu magambo ahinnye ya VRHE). Bityo, ubucucike bw'umuyoboro w'amashanyarazi bwavuzwe (ni ukuvuga ubucucike bw'umuyoboro w'amashanyarazi bwose bwikubye na FE) bwa AA buri munsi ya 60 mA cm−2 (Ishusho ya 1b n'Imbonerahamwe y'Inyongera ya 1). Ubucucike bw'umuyoboro w'amashanyarazi buri munsi cyane y'ibikenewe mu nganda (>200 mA cm−2)15, ibi bikaba bibangamira cyane ikoranabuhanga rya electrocatalytic mu gukora AA ifite ubushobozi bwo hejuru (Ishusho ya 1a; hejuru). Kugira ngo wongere ubucucike bw'umuyoboro w'amashanyarazi, hashobora gukoreshwa ubushobozi bwiza (kuri sisitemu ya electrode eshatu) cyangwa voltage iri hejuru ya selile (kuri sisitemu ya electrode ebyiri), ari bwo buryo bworoshye bwo guhindura amashanyarazi, cyane cyane ogisijeni mu iterambere (OER). Ariko, kuri COR ku ngufu nyinshi za anodic, OER ishobora kuba umuhatanira ukomeye mu kugabanya FE ya AA, bityo ikagabanya imikorere myiza y'ingufu (Ishusho ya 1a; hasi). Urugero, dusuzumye intambwe yabanjirije iyi (Ishusho ya 1b n'Imbonerahamwe y'Inyongera ya 1), twababajwe no gusanga FE ya AA kuri SDS-modified Ni(OH)2 yagabanutse kuva kuri 93% kugera kuri 76% hamwe n'ubushobozi bwo gukoreshwa kuva kuri 1.5 VRHE kugera kuri 1.7 VRHE14, mu gihe FE ya AA kuri CuxNi1-x(OH)2/CF yagabanutse kuva kuri 93% kugera kuri 69% hamwe n'ubushobozi bwo kongera kuva kuri 1.52 VRHE kugera kuri 1.62 VRHE16. Bityo, ubucucike bw'umuvuduko wa AA buvugwa ntabwo bwiyongera ku rugero ku ngufu nyinshi, ibyo bikaba bigabanya cyane iterambere ry'imikorere ya AA, tutibagiwe n'ikoreshwa ry'ingufu nyinshi bitewe na FE nke ya AA. Uretse catalysts zishingiye kuri nikeli, catalysts zishingiye kuri kobalti nazo zagaragaje imikorere ya catalytic muri COR17,18,19. Ariko, imikorere yazo iragabanuka iyo hari ubushobozi bwinshi, kandi ugereranije na catalysts zishingiye kuri Ni, zifite imbogamizi nyinshi mu mikoreshereze y’inganda, nko guhinduka cyane kw’ibiciro n’ibikoresho bito. Kubwibyo, ni byiza guteza imbere catalysts zishingiye kuri Ni zifite ubucucike bwinshi bw’amashanyarazi na FE muri COR kugira ngo bibe ingirakamaro kugera ku musaruro mwinshi wa AA.
Muri iki gikorwa, tugaragaza ko nanosheets za vanadium (V)-modified nickel layered double hydroxide nanosheets (NiV-LDH-NS) nk'ibikoresho by'amashanyarazi bitanga umusaruro wa AA binyuze muri COR, bikora ku rugero rwagutse rw'ubushobozi hamwe na OER yagabanijwe cyane, bigatuma habaho ubucucike bwinshi bwa FE n'ubucucike bw'amashanyarazi mu turemangingo twa H-cells no mu matsinda ya electrode ya membrane (MEAs; Ishusho ya 1 b). Twabanje kwerekana ko ubushobozi bwa acetylene oxidation hejuru ya catalyst isanzwe ya Ni (OH)2 nanosheets (Ni (OH)2-NS) bugabanuka, nk'uko byari byitezwe, ku bucucike bwinshi, kuva kuri 80% kuri 1.5 VRHE kugera kuri 42% kuri 1.9 VRHE. Mu buryo bunyuranye cyane, nyuma yo guhindura Ni (OH)2 na V, NiV-LDH-NS yagaragaje ubucucike bwinshi bw'ubucucike ku bucucike runaka, kandi ikiruta byose, yakomeje FE hejuru ku rugero rwagutse rw'ubushobozi. Urugero, kuri 1.9 VRHE, yagaragaje ubucucike bw'amashanyarazi bwa 170 mA cm−2 na FE ya 83%, ikaba ari catalyst nziza ya COR muri sisitemu ya electrode eshatu (Ishusho ya 1c n'Imbonerahamwe y'inyongera ya 1). Amakuru y'igerageza n'ay'inyigo agaragaza ko V modification itera imbaraga kinetics zo kugabanya kuva kuri Ni(OH)2 kugera kuri high-valent Ni oxyhydroxides (Ni3+xOOH1-x), zikora nk'ikiciro gikora cya COR. Byongeye kandi, V modification yongereye uburyo cyclohexanone inyuzwa ku buso bwa catalyst, byagize uruhare runini mu guhagarika OER ku bushobozi bwinshi bwa anodic. Kugira ngo tugaragaze ubushobozi bwa NiV-LDH-NS mu buryo bufatika, twakoze MEA flow reactor maze tugaragaza FE ya AA (82%) ku bucucike bw'amashanyarazi bujyanye n'inganda (300 mA cm−2), iri hejuru cyane ugereranyije n'ibyavuye mu bushakashatsi bwacu bwa mbere muri membrane flow reactor (Ishusho ya 1b n'Imbonerahamwe y'inyongera ya 2). Umusaruro ujyanye na AA (1536 μmol cm−2 h−1) wari munini cyane kurusha uwabonetse hakoreshejwe uburyo bwa "thermal catalytic process" (<30 mmol gcatalyst−1 h−1). Byongeye kandi, "catalyst" yagaragaje ko ihamye neza iyo ikoreshwa na MEA, ikomeza FE >80% AA mu masaha 60 kuri 200 mA cm−2 na FE >70% AA mu masaha 58 kuri 300 mA cm−2. Amaherezo, inyigo y'ibanze y'uko ibintu bishoboka (FEA) yagaragaje ko ingamba za "electrocatalytic" zihendutse mu gukora AA zikoreshwa.
Dukurikije inyandiko zabanje, Ni(OH)2 ni catalyst isanzwe igaragaza imikorere myiza ya COR, bityo Ni(OH)2-NS13,14 yakozwe bwa mbere binyuze mu buryo bwa coprecipitation. Ingero zagaragaje imiterere ya β-Ni(OH)2, byemejwe na X-ray diffraction (XRD; Ishusho ya 2a), kandi nanosheets zoroshye cyane (ubunini: 2–3 nm, ingano yo ku ruhande: 20–50 nm) zagaragaye hakoreshejwe mikoroskopi ya elegitoroniki yoherezwa mu buryo bwo hejuru (HRTEM; Ishusho y'inyongera ya 1) na mikoroskopi ya atome force (AFM) (Ishusho y'inyongera ya 2). Guteranya nanosheets byagaragaye bitewe n'imiterere yazo yoroshye cyane.
Imiterere ya X-ray diffraction ya Ni(OH)2-NS na NiV-LDH-NS. FE, throughput, na AA current density kuri b Ni(OH)2-NS na c NiV-LDH-NS ku bushobozi butandukanye. Uduce tw'amakosa tugaragaza ihinduka risanzwe ry'ibipimo bitatu byigenga hakoreshejwe catalyst imwe. d Ishusho ya HRTEM ya NV-LDH-NS. Uduce tw'amakosa: 20 nm. Ishusho ya HAADF-STEM ya NiV-LDH-NS n'ikarita y'ibanze ijyanye nayo igaragaza ikwirakwizwa rya Ni (icyatsi kibisi), V (umuhondo), na O (ubururu). Uduce tw'amakosa: 100 nm. f Ni 2p3/2, g O 1 s, na h V 2p3/2 XPS data ya Ni(OH)2-NS (hejuru) na NiV-LDH-NS (hejuru). i FE na j ni imikorere ya AA kuri catalyst ebyiri mu mizingo 7. Uduce tw'amakosa tugaragaza ihinduka risanzwe ry'ibipimo bitatu byigenga hakoreshejwe catalyst imwe kandi turi muri 10%. Amakuru y’ibanze kuri a–c na f–j atangwa muri dosiye z’amakuru y’ibanze.
Hanyuma twasuzumye ingaruka za Ni(OH)2-NS kuri COR. Dukoresheje electrolysis ihoraho, twabonye 80% FE ya AA ku bushobozi buke (1.5 VRHE) nta OER (Ishusho ya 2b), bigaragaza ko COR ari nziza kurusha OER ku bushobozi buke bwa anodic. Umusaruro w'ingenzi wabonetse ari aside glutarike (GA) ifite FE ya 3%. Kuba hari ingano nto ya aside succinic (SA), aside malonic (MA), na aside oxalic (OA) nabyo byapimwe na HPLC (reba Ishusho y'inyongera ya 3 ku ikwirakwizwa ry'umusaruro). Nta aside formic yabonetse mu musaruro, bigaragaza ko karubone ishobora kuba ikorwa nk'umusaruro wa C1. Kugira ngo tugerageze iki gitekerezo, electrolyte yavuye muri electrolysis yuzuye ya 0.4 M cyclohexanone yahinduwe aside maze ibicuruzwa bya gaze binyuzwa mu gisubizo cya Ca(OH)2. Kubera iyo mpamvu, umuti wabaye umuyoboro, byemeza ikorwa rya karubone nyuma ya electrolysis. Ariko, bitewe n'amashanyarazi make yakozwe mu gihe cy'ikorwa ry'amashanyarazi (Ishusho ya 2b, c), ingano ya karubone ni nto kandi biragoye kuyipima. Byongeye kandi, ibindi bicuruzwa bya C2-C5 nabyo bishobora gukorwa, ariko ingano yabyo ntishobora gupimwa. Nubwo ingano yose y'ibicuruzwa bigoye kuyipima, 90% by'ibipimo byose bya electrochemical bigaragaza ko inzira nyinshi za electrochemical zabonetse, ibyo bikaba ari byo bitanga ishingiro ry'uburyo dusobanukirwa. Bitewe n'ubucucike buke bw'amashanyarazi (20 mA cm−2), umusaruro wa AA wari 97 μmol cm−2 h−1 (Ishusho ya 2b), bingana na 19 mmol h−1 g−1 hashingiwe ku mubyimba w'ibikomoka kuri katalyst (5 mg cm−2), biri hasi ugereranije n'umusaruro w'ubushyuhe (~30 mmol h−1 g−1)1. Ubwo ubushobozi bwakoreshejwe bwiyongereye kuva kuri 1.5 kugeza kuri 1.9 VRHE, nubwo ubucucike bw'amashanyarazi muri rusange bwiyongereye (kuva kuri 20 kugeza kuri 114 mA cm−2), icyarimwe habayeho igabanuka rikomeye rya AA FE, kuva kuri 80% kugeza kuri 42%. Igabanuka rya FE ku bushobozi bwiza cyane biterwa ahanini n'irushanwa rya OER. Cyane cyane kuri 1.7 VRHE, irushanwa rya OER rituma AA FE igabanuka cyane, bityo bigabanyiriza gato imikorere ya AA hamwe n'ubucucike bw'amashanyarazi muri rusange bwiyongera. Bityo, nubwo ubucucike bw'amashanyarazi bwa AA bwiyongereye kuva kuri 16 kugeza kuri 48 mA cm−2 kandi umusaruro wa AA wiyongera (kuva kuri 97 kugeza kuri 298 μmol cm−2 h−1), hakoreshejwe ingufu nyinshi (2.5 W h gAA−1 irenga kuva kuri 1.5 kugeza kuri 1.9 VRHE), bigatuma habaho kwiyongera kw'imyuka ya karuboni ya 2.7 g CO2 gAA−1 (ibisobanuro birambuye ku mibare bitangwa mu nyandiko y'inyongera ya 1). OER yavuzwe mbere nk'umuhatana na COR reaction ku bushobozi bwinshi bwa anodic ihuye na raporo zabanje kandi ni imbogamizi rusange mu kunoza umusaruro wa AA14,17.
Kugira ngo duteze imbere uburyo bwiza bwo gukamura COR bushingiye kuri Ni(OH)2-NS, twabanje gusesengura igice gikora. Twabonye uburebure bwa cm 473-1 na cm 553-1 mu bisubizo byacu bya Raman spectroscopy (Ishusho y'inyongera ya 4), bihuye no gupfunyika no kwaguka kw'imigozi ya Ni3+-O muri NiOOH. Byaragaragaye ko NiOOH ari umusaruro wo kugabanuka kwa Ni(OH)2 no kwegerana kwa Ni(OH)O kuri anodic potentials, kandi mu by'ukuri ni igice gikora muri oxidation ya electrocatalytic20,21. Kubwibyo, twiteze ko kwihutisha inzira yo kongera kubaka igice cya Ni(OH)2 kuri NiOOH bishobora kongera imikorere ya COR.
Twagerageje guhindura Ni(OH)2 dukoresheje ibyuma bitandukanye kuko byagaragaye ko guhindura heteroatom bitera kongera kubaka mu buryo bw'impinduka muri okiside z'icyuma/hydroxides22,23,24. Ingero zakozwe hifashishijwe uburyo bwa Ni hamwe n'icyitegererezo cya kabiri cy'icyuma. Mu ngero zitandukanye zahinduwe n'icyuma, icyitegererezo cyahinduwe na V (igipimo cya atome cya V:Ni 1:8) (cyitwa NiV-LDH-NS) cyagaragaje ubucucike bw'amashanyarazi buri hejuru muri COR (Ishusho y'inyongera ya 5) kandi ikiruta byose, AA FE iri hejuru ku idirishya rinini ry'ubushobozi. By'umwihariko, ku bucucike buke (1.5 VRHE), ubucucike bw'amashanyarazi bwa NiV-LDH-NS bwari hejuru inshuro 1.9 kurusha ubwa Ni(OH)2-NS (39 vs. 20 mA cm−2), kandi AA FE yari ihwanye kuri catalysts zombi (83% vs. 80%). Bitewe n'ubucucike bw'amashanyarazi buri hejuru ndetse na FE AA isa nayo, umusaruro wa NiV-LDH-NS uri hejuru inshuro 2.1 kurusha uwa Ni(OH)2-NS (204 vs. 97 μmol cm−2 h−1), bigaragaza ingaruka zo guteza imbere impinduka za V ku bucucike bw'amashanyarazi ku bushobozi buke (Ishusho ya 2c).
Kubera ko ubushobozi bukoreshwa bwiyongera (urugero, 1.9 VRHE), ubucucike bw'ubu kuri NiV-LDH-NS buri hejuru inshuro 1.5 kurusha ubwo kuri Ni(OH)2-NS (170 vs. 114 mA cm−2), kandi ukwiyongera kungana n'uko biri ku bushobozi buri hasi (kwiyongera inshuro 1.9). By'umwihariko, NiV-LDH-NS yagumanye AA FE iri hejuru (83%) kandi OER yaragabanutse cyane (O2 FE 4%; Ishusho ya 2c), irusha Ni(OH)2-NS gukora neza ndetse n'ibikatali byavuzwe mbere bifite AA FE iri hasi cyane ku bushobozi buri hejuru bwa anodic (Imbonerahamwe y'inyongera ya 1). Bitewe n’uko FE nyinshi ya AA mu gihe cy’izuba rinini (1.5–1.9 VRHE), igipimo cya AA cya 867 μmol cm−2 h−1 (kingana na 174.3 mmol g−1 h−1) cyagezweho kuri 1.9 VRHE, bigaragaza imikorere myiza muri sisitemu za electrocatalytic ndetse na thermocatalytic iyo igikorwa cyagabanutse bitewe n’ubwinshi bw’ibipimo bya NiV-LDH-NS (Ishusho y’inyongera ya 6).
Kugira ngo dusobanukirwe ubucucike bw'amashanyarazi menshi n'ubushyuhe bwinshi bwa FE mu buryo bunini nyuma yo guhindura Ni(OH)2 na V, twagaragaje imiterere ya NiV-LDH-NS. Ibisubizo bya XRD byagaragaje ko impinduka hamwe na V zateje ihinduka ry'icyiciro kuva kuri β-Ni(OH)2 kugera kuri α-Ni(OH)2, kandi nta bwoko bwa crystalline bufitanye isano na V bwabonetse (Ishusho ya 2a). Ibisubizo bya HRTEM bigaragaza ko NiV-LDH-NS iragwa imiterere ya nanosheets za Ni(OH)2-NS nto cyane kandi zifite ingano zisa ku ruhande (Ishusho ya 2d). Ibipimo bya AFM byagaragaje icyerekezo gikomeye cyo guteranya nanosheets, bigatuma ubunini bupimwe bwa 7 nm (Ishusho y'inyongera ya 7), buruta ubwa Ni(OH)2-NS (ubunini: 2–3 nm). Isesengura rya X-ray spectroscopy (EDS) (Ishusho ya 2e) ryagaragaje ko ibintu bya V na Ni byari bikwirakwiriye muri nanosheets. Kugira ngo dusobanukirwe imiterere ya elegitoroniki ya V n'ingaruka zayo kuri Ni, twakoresheje X-ray photoelectron spectroscopy (XPS) (Ishusho ya 2f–h). Ni(OH)2-NS yagaragaje imiterere y’isonga rya spin-orbit rya Ni2+ (isonga ry’abagore kuri 855.6 eV, isonga rya satelite kuri 861.1 eV, Ishusho ya 2f)25. Ishusho ya XPS ya O1 s ya Ni(OH)2-NS ishobora kugabanywamo imisozi itatu, muri yo imisozi iri kuri 529.9, 530.9 na 532.8 eV iterwa na ogisijeni ya lattice (OL), itsinda rya hydroxyl (Ni-OH) na ogisijeni yinjizwa ku byangiritse ku buso (OAds), uko bikurikirana (Ishusho ya 2g)26,27,28,29. Nyuma yo guhinduranya na V, umusozi wa V 2p3/2 waragaragaye, ushobora gucibwamo imisozi itatu iri kuri 517.1 eV (V5+), 516.6 eV (V4+) na 515.8 eV (V3+), uko bikurikirana, bigaragaza ko ubwoko bwa V mu miterere buboneka cyane cyane mu miterere ya ogisijeni nyinshi (Ishusho ya 2h) 25,30,31. Byongeye kandi, umusozi wa Ni 2p kuri 855.4 eV muri NiV-LDH-NS wahindutse nabi (hafi 0.2 eV) ugereranije n'uwo muri Ni(OH)2-NS, bigaragaza ko electrons zakuwe kuri V zijya kuri Ni. Imiterere ya valence nke ya Ni yagaragaye nyuma yo guhindura V yari ihuye n'ibyavuye muri Ni K-edge X-ray absorption near-edge spectroscopy (XANES) (reba igice cya "V Modification Promotes Catalyst Reduction" kiri hepfo kugira ngo umenye byinshi). NiV-LDH-NS nyuma yo kuvurwa na COR mu gihe cy'isaha imwe yagenwe nka NiV-LDH-POST kandi yagaragajwe neza hakoreshejwe microscopy ya transmission electron, EDS mapping, X-ray diffraction, Raman spectroscopy, na XPS gupima (Ishusho y'inyongera 8 na 9). Catalysts zagumye nk'ibice bifite imiterere y'imashini ntoya cyane (Ishusho y'inyongera 8a-c). Ubukana bw'ibipimo bwaragabanutse kandi ingano ya V iragabanuka bitewe no kuvanga V no kongera kubaka catalysts (Ishusho y'inyongera 8d-f). XPS spectra yagaragaje kugabanuka k'ubukana bwa V (Ishusho y'inyongera 9), byatewe no kuvanga V. Byongeye kandi, isesengura rya O 1s spectrum (Ishusho y'inyongera ya 9d) n'ibipimo bya electron paramagnetic resonance (EPR) (Ishusho y'inyongera ya 10) byagaragaje ko ingano y'imyanda ya ogisijeni kuri NiV-LDH-NS yiyongereye nyuma y'isaha 1 ya electrolysis, ibi bishobora gutuma habaho impinduka mbi mu ngufu za Ni 2p (reba Ishusho y'inyongera ya 9 na 10 kugira ngo umenye byinshi)26,27,32,33. Bityo, NiV-LDH-NS yagaragaje impinduka nke mu miterere nyuma y'isaha 1 ya COR.
Kugira ngo twemeze uruhare runini rwa V mu guteza imbere COR, twakoze catalysts za NiV-LDH zifite ratios za atome za V:Ni zitandukanye (1:32, 1:16, na 1:4, zitwa NiV-32, NiV-16, na NiV-4, uko bikurikirana) uretse 1:8 hakoreshejwe uburyo bumwe bwo gupima. Ibisubizo bya EDS bigaragaza ko ratios za atome za V:Ni muri catalyst ziri hafi y’izabanjirije (Ishusho y’inyongera ya 11a–e). Uko V ihinduka, imbaraga za spectrum ya V 2p ziyongera, kandi ingufu zo gufatana z’agace ka Ni 2p zikomeza guhinduka zijya ku ruhande rubi (Ishusho y’inyongera ya 12). Muri icyo gihe, igipimo cya OL cyariyongereye buhoro buhoro. Ibisubizo by'ikizamini cya catalytic bigaragaza ko OER ishobora gukumirwa neza ndetse na nyuma yo guhindura V nke (igipimo cya atome cya V:Ni cya 1:32), aho O2 FE igabanuka kuva kuri 27% kugera kuri 11% kuri 1.8 VRHE nyuma yo guhindura V (Ishusho y'inyongera ya 11f). Uko igipimo cya V:Ni cyazamutse kuva kuri 1:32 kugeza kuri 1:8, ibikorwa bya catalytic byariyongereye. Ariko, uko V yahinduye V byakomeje kwiyongera (igipimo cya V:Ni cya 1:4), ubucucike bw'ubu bugenda bugabanuka, ibyo dukeka ko biterwa no kugabanuka k'ubucucike bw'ahantu hakora Ni (cyane cyane NiOOH active phase; Ishusho y'inyongera ya 11f). Bitewe n'ingaruka nziza zo guhindura V no kubungabunga ahantu hakora Ni, catalyst ifite igipimo cya V:Ni cya 1:8 yagaragaje FE na AA nyinshi cyane mu ikizamini cyo gusuzuma igipimo cya V:Ni. Kugira ngo hamenyekane neza niba igipimo cya V:Ni gikomeza kuba kimwe nyuma yo gukoresha electrolysis, imiterere y'ibice bya catalyst byakoreshejwe yaragaragajwe. Ibisubizo bigaragaza ko kuri catalysts zifite igipimo cya mbere cya V:Ni kuva kuri 1:16 kugeza kuri 1:4, igipimo cya V:Ni cyagabanutse kigera kuri 1:22 nyuma y’uko habayeho reaction, ibi bishobora kuba byaratewe no gucika kwa V bitewe no kongera kubaka catalysts (Ishusho y'inyongera ya 13). Menya ko AA FEs zihwanye zagaragaye igihe igipimo cya mbere cya V:Ni cyari kingana cyangwa kiri hejuru ya 1:16 (Ishusho y'inyongera ya 11f), ibi bishobora gusobanurwa no kongera kubaka catalysts bigatuma igipimo cya V:Ni gisa muri catalysts kigaragaza imikorere isa ya catalytic.
Kugira ngo twemeze akamaro ka V-modified Ni(OH)2 mu kongera imikorere ya COR, twakoze ubundi buryo bubiri bwa sintetike bwo kwinjiza V mu bikoresho bya Ni(OH)2-NS. Bumwe ni uburyo bwo kuvanga, naho icyitegererezo cyitwa NiV-MIX; ubundi ni uburyo bwo gukurura ibintu bukurikiranye, naho icyitegererezo cyitwa NiV-SP. Ibisobanuro birambuye ku buryo bwo guhuza ibintu bitangwa mu gice cy'Uburyo. Ikarita ya SEM-EDS yagaragaje ko V yahinduwe neza ku buso bwa Ni(OH)2-NS bw'ibipimo byombi (Ishusho y'inyongera ya 14). Ibisubizo bya electrolysis bigaragaza ko kuri 1.8 VRHE, ubushobozi bwa AA kuri electrode za NiV-MIX na NiV-SP ari 78% na 79%, byombi bigaragaza ubushobozi bwo hejuru kurusha Ni(OH)2-NS (51%). Byongeye kandi, OER kuri electrode za NiV-MIX na NiV-SP yagabanutse (FE O2: 7% na 2%, uko bikurikirana) ugereranije na Ni(OH)2-NS (FE O2: 27%). Ibi bisubizo byemeza ingaruka nziza zo guhindura V muri Ni(OH)2 ku kugabanya OER (Ishusho y'inyongera ya 14). Ariko, guhagarara kw'ibitera imbaraga byahungabanyijwe, byagaragajwe no kugabanuka kwa FE AA kuri NiV-MIX kugera kuri 45% no kuri NiV-SP kugera kuri 35% nyuma y'ingendo zirindwi za COR, bivuze ko hakenewe gukoresha uburyo bukwiye bwo gushimangira ubwoko bwa V, nko guhindura V muri lattice ya Ni(OH)2 muri NiV-LDH-NS, ari na yo catalyst y'ingenzi muri iki gikorwa.
Twanasuzumye uburyo Ni(OH)2-NS na NiV-LDH-NS zihagaze neza dukoresheje COR mu ngendo nyinshi. Uburyo bwakozwe mu gihe cy'isaha imwe kuri buri ngendo maze electrolyte irasimburwa nyuma ya buri ngendo. Nyuma ya cycle ya 7, imikorere ya FE na AA kuri Ni(OH)2-NS yagabanutseho 50% na 60%, mu gihe ubwiyongere bwa OER bwagaragaye (Ishusho ya 2i, j). Nyuma ya cycle, twasesenguye cyclic voltammetry (CV) curves za catalysts maze tubona ko peak ya oxidation ya Ni2+ yagabanutse buhoro buhoro, bigaragaza igabanuka ry'ubushobozi bwa redox bwa Ni (Ishusho y'inyongera ya 15a-c). Hamwe no kwiyongera k'umubare wa Nication muri electrolytes mu gihe cya electrolysis (Ishusho y'inyongera ya 15d), tuvuga ko kwangirika k'imikorere (kugabanuka k'umusaruro wa FE na AA) biterwa no gusohoka kwa Ni mu mashini, bigatuma substrate ya Ni ifuro igaragaza imikorere ya OER. Mu buryo bunyuranye, NiV-LDH-NS yagabanyije umuvuduko w’umusaruro wa FE na AA kugeza kuri 10% (Ishusho ya 2i, j), bigaragaza ko guhindura V byabujije neza leaching ya Ni (Ishusho y’inyongera ya 15d). Kugira ngo dusobanukirwe uburyo bwo kongera guhagarara kw’impinduka za V, twakoze imibare y’inyigo. Dukurikije inyandiko zabanje34,35, impinduka za enthalpy mu nzira yo gukuraho ibyuma bya atome z’icyuma ku buso bukora bwa catalyst zishobora gukoreshwa nk’igisobanuro gikwiye kugira ngo dusuzume uburyo catalyst ihagaze. Kubwibyo, impinduka za enthalpy mu nzira yo gukuraho ibyuma bya atome za Ni ku buso (100) bwa Ni(OH)2-NS na NiV-LDH-NS (NiOOH na NiVOOH, uko bikurikirana) zapimwe (ibisobanuro birambuye ku miterere y’icyitegererezo bivugwa mu nyandiko y’inyongera ya 2 n’Ishusho y’inyongera ya 16). Uburyo bwo gukuraho ibyuma bya Ni bivuye kuri NiOOH na NiVOOH bwagaragajwe (Ishusho y’inyongera ya 17). Ikiguzi cy'ingufu zo gukuraho Ni kuri NiVOOH (0.0325 eV) kiri hejuru ugereranyije n'icya NiOOH (0.0005 eV), bigaragaza ko guhindura V byongera umutuzo wa NiOOH.
Kugira ngo hemezwe ingaruka zo gukumira OER kuri NiV-LDH-NS, cyane cyane ku bushobozi bwinshi bwa anodic, hakozwe isuzuma ry’imiterere ya O2 ishingiye ku bushobozi ku ngero zitandukanye. Ibisubizo byagaragaje ko iyo cyclohexanone idafite, O2 kuri NiV-LDH-NS yagaragaye ku bushobozi bwa mbere bwa 1.53 VRHE, bwari munsi gato y’ubwa O2 kuri Ni(OH)2-NS (1.62 VRHE) (Ishusho y’inyongera ya 18). Ibi bisubizo bigaragaza ko gukumira OER kwa NiV-LDH-NS mu gihe cya COR bishobora kuba bidaterwa n’imikorere yayo ya OER iri hasi, ijyanye n’ubucucike bw’amashanyarazi buri hejuru gato mu miyoboro ya voltammetry ya linear sweep (LSV) kuri NiV-LDH-NS kurusha iyo kuri Ni(OH)2-NS idafite cyclohexanone (Ishusho y’inyongera ya 19). Nyuma yo gushyirwaho kwa cyclohexanone, ihindagurika rya O2 ryatinze (bishoboka ko ryatewe n'akamaro ka thermodynamic ka COR) risobanura FE nyinshi ya AA mu gace gafite ubushobozi buke. Icy'ingenzi kurushaho, ubushobozi bwa OER bwo gutangira kuri NiV-LDH-NS (1.73 VRHE) buratinda kurusha ubwo kuri Ni(OH)2-NS (1.65 VRHE), ibi bikaba bihuye na FE nyinshi ya AA na FE nke ya O2 kuri NiV-LDH-NS ku buryo bwiza (Ishusho ya 2c).
Kugira ngo dusobanukirwe neza ingaruka zo guteza imbere impinduka za V, twasesenguye kinetics ya OER na COR reaction kuri Ni(OH)2-NS na NiV-LDH-NS dupima imiturire ya Tafel. Ni ngombwa kumenya ko ubucucike bw'ubu mu gace ka Tafel buterwa na oxidation ya Ni2+ kuri Ni3+ mu gihe cy'ikizamini cya LSV kuva ku bushobozi buke kugeza ku bushobozi bwinshi. Kugira ngo tugabanye ingaruka za oxidation ya Ni2+ ku gipimo cya COR Tafel slope, twabanje gukaranga catalyst kuri 1.8 VRHE mu gihe cy'iminota 10 hanyuma dukora ibizamini bya LSV mu buryo bwo gupima inyuma, ni ukuvuga kuva ku bushobozi bwinshi kugeza ku bushobozi buke (Ishusho y'inyongera ya 20). Umurongo wa mbere wa LSV wakosowe hamwe n'indishyi ya iR 100% kugira ngo haboneke imiterere ya Tafel. Mu gihe nta cyclohexanone yari ihari, imiterere ya Tafel ya NiV-LDH-NS (41.6 mV dec−1) yari iri hasi ugereranije n’iya Ni(OH)2-NS (65.5 mV dec−1), bigaragaza ko kinetics za OER zishobora kongerwa no guhindura V (Ishusho y'inyongera ya 20c). Nyuma yo gushyiramo cyclohexanone, imiterere ya Tafel ya NiV-LDH-NS (37.3 mV dec−1) yari iri hasi ugereranyije n’iya Ni(OH)2-NS (127.4 mV dec−1), bigaragaza ko guhindura V byagize ingaruka zigaragara kuri COR ugereranije na OER (Ishusho y'inyongera ya 20d). Ibi bisubizo bigaragaza ko nubwo guhindura V kuzamura OER ku rugero runaka, byihutisha cyane kinetics za COR, bigatuma FE ya AA yiyongera.
Kugira ngo dusobanukirwe ingaruka zo guteza imbere impinduka za V zavuzwe haruguru ku mikorere ya FE na AA, twibanze ku bushakashatsi bw'imikorere. Raporo zimwe na zimwe zabanjirije iyi zagaragaje ko guhindura heteroatom bishobora kugabanya ubukana bwa catalysts no kongera ubuso bukora neza bwa electrochemical (EAS), bityo bikongera umubare w'ahantu hakora bityo bikanoza imikorere ya catalytic36,37. Kugira ngo dusuzume ibi bishoboka, twakoze ibipimo bya ECSA mbere na nyuma yo gukoresha electrochemical, kandi ibyavuye mu bushakashatsi byagaragaje ko ECSA ya Ni(OH)2-NS na NiV-LDH-NS byari bingana (Ishusho y'inyongera ya 21), hatabariwemo ingaruka z'ubucucike bw'ahantu hakora nyuma yo guhindura V ku kongera ingufu za catalytic.
Dukurikije ubumenyi bwemewe muri rusange, muri electrooxidation ya Ni(OH)2 ya alcool cyangwa izindi substrates za nucleophilic, Ni(OH)2 ibanza gutakaza electron na proton hanyuma ikagabanuka ikaba NiOOH binyuze mu ntambwe za electrochemical ku buryo runaka bwa anodic potential38,39,40,41. NiOOH yakozwe ikora nk'ubwoko bwa COR bukora neza kugira ngo ikuremo hydrogen na electron bivuye muri substrate ya nucleophilic binyuze mu ntambwe za chemical kugira ngo habeho product ya oxidized20,41. Ariko, biherutse kuvugwa ko nubwo kugabanuka kuri NiOOH bishobora kuba intambwe igena igipimo (RDS) cyo gushyiraho electrooxidation ya alcool kuri Ni(OH)2, nk'uko bivugwa mu nyandiko ziherutse, oxidation ya alcool za Ni3+ ishobora kuba inzira itunguranye binyuze mu kohereza electron zitari redox binyuze mu miyoboro ya Ni3+41,42 idakora. Dushingiye ku bushakashatsi bwakozwe mu nyandiko zimwe, twakoresheje dimethylglyoxime disodium salt octahydrate (C4H6N2Na2O2 8H2O) nk'agace k'ubushakashatsi kugira ngo dufate ireme rya Ni2+ rikomoka ku kugabanuka kwa Ni3+ mu gihe cya COR (Ishusho y'inyongera ya 22 n'Inyongera ya 3). Ibisubizo byagaragaje ireme rya Ni2+, byemeza ko kugabanuka kwa NiOOH mu buryo bwa shimi no gushonga kwa Ni(OH)2 byabayeho icyarimwe mu gihe cya COR. Kubwibyo, igikorwa cya catalytic gishobora guterwa cyane n'uburyo Ni(OH)2 igabanuka kuri NiOOH. Dushingiye kuri iri hame, twakurikiranye ubushakashatsi niba guhindura V byakwihutisha kugabanuka kwa Ni(OH)2 bityo bikanoza COR.
Twabanje gukoresha tekiniki za Raman mu buryo bwa "situ" kugira ngo tugaragaze ko NiOOH ari yo ngirangingo ikora kuri COR kuri Ni(OH)2-NS na NiV-LDH-NS twitegereje ikorwa rya NiOOH ku bushobozi bwiza n'ikoreshwa ryayo nyuma yo gushyirwaho kwa cyclohexanone, dukurikije inzira yavuzwe haruguru ya "electrochemical-chemical" (Ishusho ya 3a). Byongeye kandi, reactivity ya NiV-LDH-NS yongeye kubakwa yarenze iya Ni(OH)2-NS, nk'uko bigaragazwa no gucika vuba kw'ikimenyetso cya Ni3+–O Raman. Hanyuma twerekanye ko NiV-LDH-NS yagaragaje ubushobozi buke bwo gukora NiOOH ugereranije na Ni(OH)2-NS mu gihe cyclohexanone ihari cyangwa idafite (Ishusho ya 3b, c n'Ishusho y'inyongera ya 4c, d). Ikigaragara ni uko imikorere myiza ya OER ya NiV-LDH-NS ituma utubumbe twinshi dufata ku mboni y'imbere y'intego yo gupima Raman, bigatuma Raman peak kuri 1.55 VRHE ibura (Ishusho y'inyongera ya 4d). Dukurikije ibyavuye muri DEMS (Ishusho y'inyongera ya 18), ubucucike bw'ubu ku bushobozi buke (VRHE < 1.58 kuri Ni(OH)2-NS na VRHE < 1.53 kuri NiV-LDH-NS) ahanini biterwa no kongera kubaka ioni za Ni2+ aho kuba OER mu gihe nta cyclohexanone irimo. Bityo, peak ya oxidation ya Ni2+ mu murongo wa LSV irakomeye kurusha iya NiV-LDH-NS, bigaragaza ko guhindura V guha NiV-LDH-NS ubushobozi bwo kongera kuvugurura (reba Ishusho y'inyongera ya 19 kugira ngo ubone isesengura rirambuye).
a In situ Raman spectra ya Ni(OH)2-NS (ibumoso) na NiV-LDH-NS (iburyo) munsi ya OCP conditions nyuma yo kugabanya ubushyuhe kuri 1.5 VRHE muri 0.5 M KOH na 0.4 M cyclohexanone mu gihe cy'amasegonda 60. b In situ Raman spectra ya Ni(OH)2-NS na c NiV-LDH-NS muri 0.5 M KOH + 0.4 M cyclohexanone ku bushobozi butandukanye. d In situ XANES spectra ya Ni(OH)2-NS na NiV-LDH-NS kuri Ni K-edge muri 0.5 M KOH na e 0.5 M KOH na 0.4 M cyclohexanone. Ishusho igaragaza agace kagutse ka spectra hagati ya 8342 na 8446 eV. f Valence states ya Ni muri Ni(OH)2-NS na NiV-LDH-NS ku bushobozi butandukanye. g Muri situ Ni EXAFS spectra ya NiV-LDH-NS mbere na nyuma yo kuyishyiramo cyclohexanone ku buryo butandukanye. h Ingero z'inyigisho za Ni(OH)2-NS na NiV-LDH-NS. Hejuru: Kuri Ni(OH)2-NS, ivugurura rigenda buhoro kuva kuri Ni(OH)2-NS kugera kuri NiOOH rikora nka RDS, mu gihe cyclohexanone igabanya ubwoko bwa Ni bunini binyuze mu ntambwe za shimi kugira ngo igumane imiterere ya Ni isanzwe kugira ngo itange AA. Hasi: Kuri NiV-LDH-NS, intambwe yo kuvugurura yoroherezwa no guhindura V, bigatuma RDS iva ku ntambwe yo kuvugurura ijya ku ntambwe ya shimi. i Impinduka z'ingufu zidafite Gibbs iyo habayeho ivugurura rya Ni(OH)2-NS na NiV-LDH-NS. Amakuru y'ibanze ya aj na i atangwa muri dosiye y'amakuru y'ibanze.
Kugira ngo dukore ubushakashatsi ku miterere y’imiterere ya atome na elegitoroniki mu gihe cyo kugabanya catalyst, twakoze igerageza rya X-ray absorption spectroscopy (XAS) muri situ, ryatanze igikoresho gikomeye cyo gusuzuma imikorere y’ubwoko bwa Ni mu ntambwe eshatu zikurikiranye: OER, injection ya cyclohexanone, na COR at open circuit potential (OCP). Ishusho igaragaza spectra ya K-edge XANES ya Ni hamwe n’ubushobozi bwiyongera mbere na nyuma yo gutera cyclohexanone (Ishusho ya 3d, e). Ku bushobozi bumwe, ingufu z’inkombe z’ingufu za NiV-LDH-NS ni nziza cyane kurusha iza Ni(OH)2-NS (Ishusho ya 3d, e, inset). Impuzandengo ya valence ya Ni muri buri kibazo yapimwe hakoreshejwe linear integrated fit ya XANES spectra hamwe no gusubira inyuma kwa Ni K-edge absorption energy shift (Ishusho ya 3f), hamwe na reference spectrum yakuwe mu nyandiko zasohotse (Ishusho y’inyongera ya 23)43.
Mu ntambwe ya mbere (mbere yo gushyiramo cyclohexanone, ijyanye n'uburyo OER ikorwa; Ishusho ya 3f, ibumoso), ku bushobozi bwa catalyst itaravugururwa (<1.3 VRHE), imiterere ya valence ya Ni muri NiV-LDH-NS (+1.83) iri hasi gato ugereranyije n'iya Ni(OH)2-NS (+1.97), ishobora guterwa no kwimura electron kuva kuri V ujya kuri Ni, bihuye n'ibyavuye muri XPS byavuzwe haruguru (Ishusho ya 2f). Iyo ubushobozi burenze aho kugabanuka (1.5 VRHE), imiterere ya valence ya Ni muri NiV-LDH-NS (+3.28) igaragaza ukwiyongera kugaragara ugereranije n'iya Ni(OH)2-NS (+2.49). Ku bushobozi buri hejuru (1.8 VRHE), imiterere ya valence ya particles za Ni iboneka kuri NiV-LDH-NS (+3.64) iri hejuru ugereranyije n'iya Ni(OH)2-NS (+3.47). Nk’uko raporo ziherutse zibivuga, iyi nzira ihuye no kuremwa kw’ubwoko bwa Ni4+ bufite valent nyinshi mu miterere ya Ni3+xOOH1-x (Ni3+x ni ubwoko buvanze bwa Ni3+ na Ni4+), bwagaragaje ko butera imbere mu gukuraho umwuka mubi mu binyobwa 38,39,44. Kubwibyo, imikorere myiza ya NiV-LDH-NS muri COR ishobora guterwa no kwiyongera ko haboneka ubwoko bwa Ni4+ bufite valent nyinshi.
Mu ntambwe ya kabiri (itangira rya cyclohexanone nyuma yo gufungura impeta, Ishusho ya 3f), imiterere ya valence ya Ni kuri catalysts zombi yagabanutse cyane, ibi bikaba bihuye n'uburyo bwo kugabanya Ni3+xOOH1-x hakoreshejwe cyclohexanone, ibi bikaba bihuye n'ibyavuye muri spectroscopy ya Raman muri situ (Ishusho ya 3a), naho imiterere ya valence ya Ni hafi gusubira ku mimerere ya mbere (intambwe ya mbere ku bushobozi buke), bigaragaza ko inzira ya redox ya Ni3+xOOH1-x ishobora gusubira inyuma.
Mu ntambwe ya gatatu (inzira ya COR) kuri COR potentials (1.5 na 1.8 VRHE; Ishusho ya 3f, iburyo), imiterere ya valence ya Ni muri Ni (OH)2-NS yiyongereyeho gato (+2.16 na +2.40), ikaba iri hasi cyane ugereranyije n'ubushobozi bumwe mu ntambwe ya mbere (+2.49 na +3.47). Ibi bisubizo bigaragaza ko nyuma yo guterwa cyclohexanone, COR igabanywa na kinetically bitewe na oxidation ya Ni2+ kuri Ni3+x (ni ukuvuga, reconstruction ya Ni) aho kuba intambwe ya chemical hagati ya NiOOH na cyclohexanone kuri Ni (OH)2-NS, bigatuma Ni iba mu mimerere ya valence ntoya. Bityo, twanzura ko reconstruction ya Ni ishobora gukora nka RDS muri COR muri Ni (OH)2-NS. Mu buryo bunyuranye, NiV-LDH-NS yagumanye valence iri hejuru cyane y’ubwoko bwa Ni (>3) mu gihe cya COR, kandi valence yagabanutseho gato cyane (munsi ya 0.2) ugereranije n’intambwe ya mbere ku bushobozi bumwe (1.65 na 1.8 VRHE), bigaragaza ko guhindura V byateje imbere ogisijeni ya Ni2+ ikaba Ni3+x, bituma inzira yo kugabanya Ni yihuta kurusha intambwe ya shimi yo kugabanya cyclohexanone. Ibisubizo bya X-ray absorption fine structure (EXAFS) byagaragaje kandi impinduka yuzuye ya Ni–O (kuva kuri 1.6 kugeza kuri 1.4 Å) na Ni–Ni(V) (kuva kuri 2.8 kugeza kuri 2.4 Å) bonds mu gihe hari cyclohexanone. Ibi bihuye no kongera kubaka phase ya Ni(OH)2 kugeza kuri phase ya NiOOH no kugabanya shimi kwa phase ya NiOOH hakoreshejwe cyclohexanone (Ishusho ya 3g). Ariko, cyclohexanone yabangamiye cyane uburyo Ni(OH)2-NS igabanuka (reba Inyongera 4 n'Inyongera 24 ku bisobanuro birambuye).
Muri rusange, kuri Ni(OH)2-NS (Ishusho ya 3h, hejuru), intambwe yo kugabanya buhoro buhoro kuva kuri Ni(OH)2 kugeza kuri NiOOH ishobora kuba RDS y'inzira rusange ya COR aho kuba intambwe ya shimi yo gukora AA kuva kuri cyclohexanone mu gihe cyo kugabanya NiOOH mu buvuzi. Kuri NiV-LDH-NS (Ishusho ya 3h, hasi), guhindura V byongera kinetics ya oxidation ya Ni2+ kugeza kuri Ni3+x, bityo byihutisha ikorwa rya NiVOOH (aho gukoreshwa no kugabanya shimi), ibyo bigatuma RDS ijya ku ntambwe ya shimi. Kugira ngo dusobanukirwe ivugurura rya Ni riterwa no guhindura V, twakoze imibare y'inyongera. Nkuko bigaragara ku Ishusho ya 3h, twiganye inzira yo kongera kubaka Ni(OH)2-NS na NiV-LDH-NS. Amatsinda ya lattice hydroxyl kuri Ni(OH)2-NS na NiV-LDH-NS akurwaho protonation binyuze mu gukura OH- muri electrolyte kugira ngo habeho ogisijeni ya lattice idafite electron. Inzira za shimi zijyanye nayo ni izi zikurikira:
Impinduka y’ingufu zidafite Gibbs mu gusana yarabazwe (Ishusho ya 3i), maze NiV-LDH-NS (0.81 eV) igaragaza impinduka nto cyane y’ingufu zidafite Gibbs ugereranyije na Ni (OH)2-NS (1.66 eV), bigaragaza ko guhindura V byagabanyije voltage isabwa mu gusana Ni. Twizera ko guteza imbere gusana bishobora kugabanya imbogamizi z’ingufu za COR yose (reba inyigo y’uburyo bwo gusubiza hepfo kugira ngo umenye ibisobanuro birambuye), bityo bikihutisha reaction ku bucucike bw’umuvuduko w’amashanyarazi uri hejuru.
Isesengura ryavuzwe haruguru rigaragaza ko guhindura V bitera gusubiranamo vuba kwa Ni(OH)2, bityo byongera igipimo cy’imyanzuro, ndetse n’ubucucike bwa COR. Ariko, ahantu ha Ni3+x na ho hashobora guteza imbere ibikorwa bya OER. Ukurikije umurongo wa LSV udafite cyclohexanone, biragaragara ko ubucucike bwa NiV-LDH-NS buri hejuru kurusha ubwa Ni(OH)2-NS (Ishusho y’inyongera ya 19), bituma reaction za COR na OER zigira reactions zo guhangana. Kubwibyo, FE ya AA iri hejuru cyane kurusha iya NiV-LDH-NS ntishobora gusobanurwa neza na V modification itera imbere rearranging phase.
Muri rusange byemewe ko mu byuma bya alkaline, uburyo electrooxidation reactions za substrates za nucleophilic zikunze gukurikiza icyitegererezo cya Langmuir-Hinshelwood (LH). By’umwihariko, substrate na OH− anions bihuzwa ku buso bwa catalyst, kandi OH− inyuzwamo oxidized kuri active hydroxyl groups (OH*), zikora nk'electrophiles zo gusohora oxidization ya nucleophiles, uburyo bwagaragajwe mbere n'amakuru y'igerageza n'/cyangwa imibare y'inyigisho45,46,47. Bityo, ubwinshi bwa reactants n'ikigereranyo cyazo (organic substrate na OH−) bishobora kugenzura uburyo reactant inyuzwamo ku buso bwa catalyst, bityo bigira ingaruka kuri FE n'umusaruro w'umusaruro 14,48,49,50. Muri uru rubanza, dutekereza ko ubuso bwa cyclohexanone bwinshi muri NiV-LDH-NS bukunda inzira ya COR, kandi ku rundi ruhande, ubuso bwa cyclohexanone buke muri Ni(OH)2-NS bukunda inzira ya OER.
Kugira ngo tugerageze igitekerezo cyavuzwe haruguru, twabanje gukora igerageza ribiri rijyanye n'ubwinshi bw'ibitera imbaraga (C, cyclohexanone, na COH−). Igerageza rya mbere ryakozwe hakoreshejwe electrolysis ku bushobozi buhoraho (1.8 VRHE) kuri catalysts za Ni(OH)2-NS na NiV-LDH-NS zifite ibipimo bitandukanye bya cyclohexanone C (0.05 ~ 0.45 M) n'ibipimo bidahinduka bya COH− (0.5 M). Hanyuma, umusaruro wa FE na AA warabazwe. Kuri catalyst ya NiV-LDH-NS, isano iri hagati y'umusaruro wa AA na cyclohexanone C yagaragaje umurongo usanzwe wa "ubwoko bw'ibirunga" mu buryo bwa LH (Ishusho ya 4a), bigaragaza ko ubwinshi bwa cyclohexanone buhangana n'uburyo OH− ikwirakwira. Mu gihe kuri Ni(OH)2-NS, umusaruro wa AA wiyongereye cyane bitewe n’ubwiyongere bwa C ya cyclohexanone kuva kuri 0.05 kugeza kuri 0.45 M, bigaragaza ko nubwo ubwinshi bwa cyclohexanone bwari hejuru (0.45 M), ubuso bwayo bwari bukiri hasi cyane. Byongeye kandi, hamwe n’ubwiyongere bwa COH− kugeza kuri 1.5 M, hagaragaye "ubwoko bw’ibirunga" kuri Ni(OH)2-NS bitewe na C ya cyclohexanone, kandi aho imikorere igarukira haratinze ugereranije na NiV-LDH-NS, birushaho kugaragaza ko cyclohexanone idakomeye kuri Ni(OH)2-NS (Ishusho y’inyongera ya 25a n’Icyitonderwa cya 5). Byongeye kandi, FE ya AA kuri NiV-LDH-NS yari ifite ubushobozi bwo kwiyumvamo C-cyclohexanone kandi yariyongereye cyane igera kuri 80% ubwo C-cyclohexanone yongerwaga kuva kuri 0.05 M ikagera kuri 0.3 M, bigaragaza ko cyclohexanone yakungahaye kuri NiV-LDH-NS byoroshye (Ishusho ya 4b). Ibinyuranye n'ibyo, kongera ingano ya C-cyclohexanone ntibyabujije cyane OER kuri Ni(OH)2-NS, bishobora guterwa no kudashyirwa neza kwa cyclohexanone. Ku rundi ruhande, iperereza ryimbitse ku kwishingikiriza kwa COH− ku bushobozi bwa catalytic ryagaragaje kandi ko kwinjira kwa cyclohexanone kwarushijeho kuba kwiza ugereranije na NiV-LDH-NS, ishobora kwihanganira COH− nyinshi mu gihe cya COR idagabanyije FE ya AA (Ishusho y'inyongera ya 25b, c na Note 5).
Umusaruro wa AA na EF bya b Ni(OH)2-NS na NiV-LDH-NS kuri cyclohexanone hamwe na C zitandukanye muri 0.5 M KOH. c Ingufu zo gushyiramo cyclohexanone kuri NiOOH na NiVOOH. d FE ya AA kuri Ni(OH)2-NS na NiV-LDH-NS muri 0.5 M KOH na 0.4 M cyclohexanone kuri 1.80 VRHE hakoreshejwe ingamba zihoraho kandi zidahindagurika. Uduce tw'amakosa tugaragaza ihinduka risanzwe ry'ibipimo bitatu byigenga hakoreshejwe icyitegererezo kimwe kandi turi muri 10%. e Hejuru: Kuri Ni(OH)2-NS, cyclohexanone ifite ubuso buke bwa C ishyirwamo cyclohexanone buhoro, bigatuma habaho ipiganwa rikomeye kuri OER. Hasi: Kuri NiV-LDH-NS, ubwinshi bwinshi bwa cyclohexanone C bugaragara hamwe no kwiyongera k'ubwiyongere bwa cyclohexanone, bigatuma OER igabanuka. Amakuru y’ibanze kuri a–d aboneka muri dosiye y’amakuru y’ibanze.
Kugira ngo tugerageze uburyo bwo kongera ubushobozi bwo gukoresha cyclohexanone kuri NiV-LDH-NS, twakoresheje electrochemical coupled quartz crystal microbalance (E-QCM) kugira ngo dukurikirane impinduka mu bwinshi bw'ubwoko bwatewe mu gihe nyacyo. Ibisubizo byagaragaje ko ubushobozi bwa mbere bwo gukoresha cyclohexanone kuri NiV-LDH-NS bwari bunini inshuro 1.6 kurusha ubwo kuri Ni(OH)2-NS muri OCP state, kandi iri tandukaniro mu bushobozi bwo gukoresha cyclohexanone ryarushijeho kwiyongera uko ubushobozi bwagendaga bugera kuri 1.5 VRHE (Ishusho y'inyongera ya 26). Imibare ya DFT ya spin-polarized yakozwe kugira ngo hamenyekane imyitwarire yo gukoresha cyclohexanone kuri NiOOH na NiVOOH (Ishusho ya 4c). Cyclohexanone yinjirira kuri Ni-center kuri NiOOH ifite ingufu zo kuyungurura (Eads) za -0.57 eV, mu gihe cyclohexanone ishobora kwinjirira kuri Ni-center cyangwa V-center kuri NiVOOH, aho V-center itanga Eads nkeya cyane (-0.69 eV), hakurikijwe uko cyclohexanone yinjirira cyane kuri NiVOOH.
Kugira ngo turusheho kwemeza ko kwiyongera k’umunyungugu wa cyclohexanone bishobora guteza imbere ikorwa rya AA no gukumira OER, twakoresheje ingamba zo gukusanya cyclohexanone ku buso bwa catalyst (kuri Ni(OH)2-NS na NiV-LDH-NS), byahumetswe n’amakuru yabanje. 51, 52 By’umwihariko, twakoresheje ubushobozi bwa 1.8 VRHE kuri COR, hanyuma tuyihindura kuri OCP, hanyuma tuyisubiza kuri 1.8 VRHE. Muri iki gihe, cyclohexanone ishobora kwirunda ku buso bwa catalyst muri OCP hagati ya electrolyses (reba igice cya Methods kugirango umenye uburyo burambuye bwo gukora). Ibisubizo byagaragaje ko kuri Ni(OH)2-NS na NiV-LDH-NS, gukoresha electrolysis ishobora gukusanya imikorere ya catalytic ugereranije na electrolysis ishobora guhoraho (Ishusho ya 4d). Ikigaragara ni uko Ni(OH)2-NS yagaragaje iterambere rikomeye muri COR (AA FE: kuva kuri 51% kugeza kuri 82%) no kugabanya OER (O2 FE: kuva kuri 27% kugeza kuri 4%) kurusha NiV-LDH-NS, byatewe nuko ubwiyongere bwa cyclohexanone bwashoboraga kunozwa ku rugero runini kuri catalyst ifite ubushobozi buke bwo kwinjiza (ni ukuvuga Ni(OH)2-NS) hakoreshejwe electrolysis ihoraho.
Muri rusange, guhagarika OER kuri NiV-LDH-NS bishobora guterwa no kwiyongera k’uburyo cyclohexanone ikwirakwira (Ishusho ya 4e). Kuri Ni(OH)2-NS (Ishusho ya 4e, hejuru), uburyo cyclohexanone ikwirakwira buhoro buhoro byatumye cyclohexanone ikwirakwira buhoro buhoro ndetse na OH* nyinshi ku buso bwa catalyst. Kubwibyo, ubwoko bwa OH* bwinshi buzatuma habaho ipiganwa rikomeye kuri OER kandi bigabanye FE ya AA. Mu buryo bunyuranye, kuri NiV-LDH-NS (Ishusho ya 4e, hasi), impinduka ya V yongereye ubushobozi bwo gutera cyclohexanone, bityo yongera ubuso bwa C bwa cyclohexanone kandi ikoresha neza ubwoko bwa OH* bwashyizwemo COR, iteza imbere ikorwa rya AA kandi ikabuza OER.
Uretse gukora ubushakashatsi ku ngaruka zo guhindura V ku kongera kubaka ubwoko bwa Ni na adsorption ya cyclohexanone, twanakoze ubushakashatsi ku niba V ihindura inzira yo gushyiraho AA kuva kuri COR. Inzira nyinshi zitandukanye za COR zatanzwe mu nyandiko, kandi twasesenguye ubushobozi bwazo muri sisitemu yacu yo gusubiza (reba Ishusho y'inyongera ya 27 n'Inyongera ya 6 kugira ngo umenye byinshi)13,14,26. Ubwa mbere, byatangajwe ko intambwe ya mbere y'inzira ya COR ishobora kuba irimo oxidation ya mbere ya cyclohexanone kugira ngo habeho 2-hydroxycyclohexanone (2)13,14. Kugira ngo twemeze uko ibintu byagenze, twakoresheje 5,5-dimethyl-1-pyrrolidine N-oxide (DMPO) kugira ngo dufate intermediates zikora zinjira ku buso bwa catalyst kandi twiga EPR. Ibisubizo bya EPR byagaragaje ko hari radicals za C-centered (R) na radicals za hydroxyl (OH) kuri catalysts zombi mu gihe cya COR, bigaragaza ko Cα − H dehydrogenation ya cyclohexanone ikora radical ya enolate iri hagati (1), hanyuma OH* ikongera gukurwamo oxidation (Ishusho ya 5a n'Ishusho y'inyongera ya 28). Nubwo intermediates zimwe zabonetse kuri catalysts zombi, agace k'ikimenyetso cya R kuri NiV-LDH-NS kari hejuru ugereranyije n'aka Ni(OH)2-NS, bishobora guterwa n'ubushobozi bwo kongera kwinjiza cyclohexanone (Imbonerahamwe y'inyongera ya 3 n'Icyitonderwa cya 7). Twakoresheje kandi 2 na 1,2-cyclohexanedione (3) nk'ibice bitangira gukoreshwa mu gupima niba V yahindura intambwe ya oxidation ikurikiraho. Ibisubizo bya electrolysis by’ibice bishobora kuba intermediates (2 na 3) kuri Ni(OH)2-NS na NiV-LDH-NS byagaragaje uburyo ibicuruzwa bisa, bigaragaza ko reaction ya COR kuri Ni(OH)2-NS cyangwa NiV-LDH-NS yanyuze mu nzira zisa (Ishusho ya 5b). Byongeye kandi, AA yari umusaruro w’ingenzi gusa igihe 2 yakoreshejwe nk'ikinyabutabire, bigaragaza ko AA yabonetse binyuze mu nzira ya oxidation itaziguye binyuze mu gucika kw'umugozi wa Cα − Cβ wa 2 aho kuba oxidation yakurikiyeho kuri 3 kuri catalysts zombi, kuko ahanini yahinduwe GA ubwo 3 yakoreshwaga nk'ikinyabutabire cyo gutangira (Ishusho z'inyongera 29, 30).
Ikimenyetso cya EPR cya NiV-LDH-NS muri 0.5 M KOH + 0.4 M cyclohexanone. b Ibisubizo by'isesengura rya electrocatalytic rya 2-hydroxycyclohexanone (2) na 1,2-cyclohexanedione (3). Electrolysis yakozwe muri 0.5 M KOH na 0.1 M 2 cyangwa 3 kuri 1.8 VRE mu gihe cy'isaha imwe. Uduce tw'amakosa tugaragaza ihinduka risanzwe ry'ibipimo bibiri byigenga hakoreshejwe catalyst imwe. c Inzira zatanzwe zo gusubiza za COR kuri catalysts ebyiri. d Ishusho ya schematic y'inzira ya COR kuri Ni(OH)2-NS (ibumoso) na d NiV-LDH-NS (iburyo). Utwambi dutukura tugaragaza intambwe ihinduka rya V riteza imbere muri gahunda ya COR. Amakuru y'umwimerere kuri a na b atangwa muri dosiye y'amakuru y'umwimerere.
Muri rusange, twerekanye ko Ni(OH)2-NS na NiV-LDH-NS bitera COR imbaraga binyuze mu nzira isa: cyclohexanone yinjizwa ku buso bwa catalyst, igakurwamo umwuka hanyuma igatakaza electron kugira ngo ikore 1, hanyuma OH* igahinduka oxidized kugira ngo ikore 2, hagakurikiraho impinduka nyinshi kugira ngo ikore AA (Ishusho ya 5c). Ariko, ubwo cyclohexanone yakoreshwaga nk'ikinyabutabire, OER yagaragaye gusa kuri Ni(OH)2-NS, mu gihe ingano nto ya ogisijeni yakusanyijwe ubwo 2 na 3 byakoreshwaga nk'ikinyabutabire. Bityo, itandukaniro ryagaragaye mu mikorere ya catalyst rishobora guterwa n'impinduka mu nzitizi y'ingufu za RDS n'ubushobozi bwo kunyuzwa kwa cyclohexanone biterwa no guhinduka kwa V aho kuba impinduka mu nzira ya reaction. Bityo twasesenguye RDS y'inzira za reaction kuri catalyst zombi. Ibisubizo byavuzwe haruguru bya X-ray acoustic spectroscopy bigaragaza ko guhindura V bihindura RDS muri COR reaction kuva ku cyiciro cyo kongera kubaka kugera ku cyiciro cya chemical, bigatuma NiOOH phase na high-valent Ni species ziguma kuri NiV-LDH-NS (Ishusho ya 3f, Ishusho y'inyongera ya 24, n'Icyitonderwa cya 4). Twasesenguye kandi inzira z'inyito zigaragazwa n'ubucucike bw'ubu muri buri gice cy'uturere dutandukanye dushobora gupimwa mu gihe cyo gupima CV (reba Ishusho y'inyongera ya 31 n'Icyitonderwa cya 8 ku bisobanuro birambuye) kandi dukora igerageza rya H/D kinetic isotope exchange, ryagaragaje hamwe ko RDS ya COR kuri NiV-LDH-NS ikubiyemo gucika kw'imigozi ya Cα − H mu cyiciro cya chemical aho kuba ku cyiciro cyo kugabanya (reba Ishusho y'inyongera ya 32 n'Icyitonderwa cya 8 ku bisobanuro birambuye).
Hashingiwe ku isesengura ryavuzwe haruguru, ingaruka rusange zo guhindura V zigaragara ku Ishusho ya 5d. Kataloge ya Ni(OH)2-NS na NiV-LDH-NS ikorerwa ivugurura ry’ubuso ku mbaraga nyinshi za anodic kandi igatera COR imbaraga binyuze mu nzira nk’iyo. Kuri Ni(OH)2-NS (Ishusho ya 5d, ibumoso), intambwe yo kongera kubaka ni RDS mu gihe cya COR; mu gihe kuri NiV-LDH-NS (Ishusho ya 5d, iburyo), guhindura V byihutishije cyane inzira yo kongera kubaka kandi bihindura RDS muri Cα−H dehydrogenation ya cyclohexanone ihinduka 1. Byongeye kandi, cyclohexanone yatewe ahantu ha V kandi yongerewe kuri NiV-LDH-NS, byatumye OER ihagarikwa.
Dukurikije imikorere myiza ya NiV-LDH-NS ifite amashanyarazi menshi hamwe na FE nyinshi mu buryo bwinshi, twakoze MEA kugira ngo tugere ku musaruro uhoraho wa AA. MEA yateranijwe hakoreshejwe NiV-LDH-NS nk'anode, PtRu/C y'ubucuruzi nk'umuyoboro wa cathode53 n'urukiramende rw'ihindagurika ry'aniyoni (ubwoko: FAA-3-50) (Ishusho ya 6a n'Ishusho y'inyongera ya 33)54. Kubera ko voltage y'uturemangingo yagabanutse kandi FE ya AA ikaba ingana na 0.5 M KOH mu bushakashatsi bwavuzwe haruguru, igipimo cya anolyte cyatunganyijwe kugera kuri 1 M KOH (Ishusho y'inyongera ya 25c). Imirongo ya LSV yanditswe igaragara ku Ishusho y'inyongera ya 34, igaragaza ko ubushobozi bwa COR bwa NiV-LDH-NS buri hejuru cyane ugereranyije n'ubwa Ni(OH)2-NS. Kugira ngo hagaragazwe ko NiV-LDH-NS ari nziza cyane, hakozwe electrolysis y’umuyoboro uhoraho w’amashanyarazi hakoreshejwe ubucucike bw’umuyoboro w’amashanyarazi buri hagati ya 50 na 500 mA cm−2 kandi voltage y’uturemangingo ijyanye nayo yaranditswe. Ibisubizo byagaragaje ko NiV-LDH-NS yagaragaje voltage y’uturemangingo ya 1.76 V ku bucucike bw’umuyoboro w’amashanyarazi bwa 300 mA cm−2, yari munsi ya 16% ugereranyije n’iya Ni(OH)2-NS (2.09 V), bigaragaza ko ifite ingufu nyinshi mu gukora AA (Ishusho ya 6b).
Ishusho y'ishusho ya bateri igenda. b Voltage y'ingirabuzimafatizo idafite iR kuri Ni(OH)2-NS na NiV-LDH-NS muri 1 M KOH na 0.4 M cyclohexanone ku bucucike butandukanye bw'umuyoboro w'amashanyarazi. c AA na FE bitanga umusaruro kuri Ni(OH)2-NS na NiV-LDH-NS ku bucucike butandukanye bw'umuyoboro w'amashanyarazi. Uduce tw'amakosa tugaragaza ihinduka risanzwe ry'ibipimo bibiri byigenga hakoreshejwe catalyst imwe. d Kugereranya imikorere ya catalytic y'akazi kacu n'izindi sisitemu za bateri igenda yavuzwe14,17,19. Ibipimo bya reaction n'imiterere ya reaction byanditse mu buryo burambuye mu Imbonerahamwe y'inyongera ya 2. e Voltage y'ingirabuzimafatizo na FE ya AA kuri NiV-LDH-NS kuri 200 na 300 mA cm−2 mu igerageza ry'igihe kirekire, uko bikurikirana. Amakuru ya fatizo kuri be atangwa nk'idosiye y'amakuru ya fatizo.
Hagati aho, nk'uko bigaragara ku Ishusho ya 6c, NiV-LDH-NS yagumanye FE nziza (83% kugeza 61%) ku bucucike buri hejuru bw'umuvuduko w'amazi (200 kugeza 500 mA cm-2), bityo bikongera umusaruro wa AA (1031 kugeza 1900 μmol cm-2 h-1). Hagati aho, 0.8% gusa bya anion za aside adipic zagaragaye mu gice cya cathode nyuma ya electrolysis, bigaragaza ko ihindagurika rya cyclohexanone ritari rikomeye muri twe (Ishusho y'inyongera ya 35). Mu buryo bunyuranye, hamwe n'ubwiyongere bumwe bw'ubucucike bw'umuvuduko w'amazi, FE ya AA kuri Ni(OH)2-NS yagabanutse kuva kuri 61% igera kuri 34%, byatumye bigorana kunoza umusaruro wa AA (762 kugeza 1050 μmol cm-2 h-1). By’umwihariko, imikorere ya AA yagabanutse gato bitewe n’irushanwa rikomeye rya OER, bityo FE ya AA igabanuka cyane hamwe n’ubwiyongere bw’ubucucike bw’ubushyuhe (kuva kuri 200 kugeza 250 mA cm−2, Ishusho y’inyongera ya 5). Uko tubizi neza, ibisubizo bya catalytic bikoresha MEA hamwe na catalysts za NiV-LDH-NS biruta cyane imikorere ya reactors zavuzwe mbere hamwe na catalysts zishingiye kuri Ni (Imbonerahamwe y’inyongera ya 2). Byongeye kandi, nk’uko bigaragara ku Ishusho ya 6d, NiV-LDH-NS yagaragaje ibyiza bikomeye mu bijyanye n’ubucucike bw’ubushyuhe, voltage y’uturemangingo, na FE ya AA ugereranije na catalyst ishingiye kuri Co-based ikora neza, ni ukuvuga, Co3O4 ishyigikiwe na graphene (Co3O4/GDY)17. Byongeye kandi, twasuzumye ikoreshwa ry'ingufu mu musaruro wa AA kandi twerekanye ko ikoreshwa rya AA ryari rito cyane, 2.4 W h gAA-1 gusa ku bucucike bw'amashanyarazi bwa 300 mA cm-2 na voltage y'uturemangingo ya 1.76 V (imibare irambuye itangwa mu nyandiko y'inyongera ya 1). Ugereranije n'umusaruro mwiza wa 4.1 W h gAA-1 kuri Co3O4/GDY wavuzwe mbere, ikoreshwa ry'ingufu mu musaruro wa AA mu kazi kacu ryagabanutseho 42% kandi umusaruro wiyongereyeho inshuro 4 (1536 vs. 319 μmol cm-2 h-1)17.
Ubudahangarwa bwa catalyst ya NiV-LDH-NS yo gukora AA mu gihe kirekire muri MEA bwapimwe ku bucucike bwa 200 na 300 mA cm-2, uko bikurikirana (Ishusho ya 6e). Kubera ko OH− ikoreshwa vuba ku bucucike bw'amashanyarazi buri hejuru, igipimo cyo kuvugurura electrolyte kuri 300 mA cm-2 kiri hejuru kuruta icyo kuri 200 mA cm-2 (reba agace gato ka "Ibipimo bya Electrochemical" kugira ngo umenye ibisobanuro birambuye). Ku bucucike bwa 200 mA cm-2, impuzandengo ya COR yari 93% mu masaha 6 ya mbere, hanyuma igabanuka gato igera kuri 81% nyuma y'amasaha 60, mu gihe voltage y'uturemangingo yiyongereyeho gato 7% (kuva kuri 1.62 V kugeza kuri 1.73 V, bigaragaza ko ibudahangarwa bwiza. Kubera ko ubucucike bw'amashanyarazi bwazamutse bukagera kuri 300 mA cm−2, ubushobozi bwa AA bwakomeje kuba nta gihinduka (bwagabanutse kuva kuri 85% kugera kuri 72%), ariko voltage y'uturemangingo yariyongereye cyane (kuva kuri 1.71 kugeza kuri 2.09 V, bingana na 22%) mu gihe cy'ikizamini cy'amasaha 46 (Ishusho ya 6e). Twibwira ko impamvu nyamukuru yo kwangirika kw'imikorere ari ukwangirika kwa anion exchange membrane (AEM) na cyclohexanone, bigatuma imbaraga z'uturemangingo ziyongera kandi ingufu z'uturemangingo ziyongera (Ishusho y'inyongera ya 36), hamwe no kuva gato k'amashanyarazi ava kuri anode ajya kuri cathode, bigatuma ingano ya anolyte igabanuka kandi electrolysis igahagarara. Byongeye kandi, kugabanuka kwa FE ya AA bishobora guterwa no kuva kwa catalysts, bituma ifuro rya Ni rifunguka kuri OER. Kugira ngo tugaragaze ingaruka za AEM yangiritse ku kwangirika k'ubudahangarwa kuri 300 mA cm−2, twayisimbuje AEM nshya nyuma y'amasaha 46 yo gukoresha electrolysis. Nkuko byari byitezwe, ubushobozi bwa catalytic bwasubiwemo neza, aho voltage y'uturemangingo yagabanutse cyane kugera ku gaciro k'ibanze (kuva kuri 2.09 kugeza kuri 1.71 V) hanyuma ikongera gato mu masaha 12 yakurikiyeho yo gukoresha electrolysis (kuva kuri 1.71 kugeza kuri 1.79 V, kwiyongera kwa 5%; Ishusho ya 6e).
Muri rusange, twashoboye kugera ku masaha 60 y’umusaruro wa AA uhoraho ku bucucike bw’umuyoboro wa 200 mA cm−2, bigaragaza ko voltage ya FE na selile ya AA zibungabunzwe neza. Twagerageje kandi ubucucike bw’umuyoboro wa 300 mA cm−2 maze tugera ku bucucike bw’umuyoboro wa 58, dusimbuza AEM indi nshya nyuma y’amasaha 46. Ubushakashatsi bwavuzwe haruguru bwerekana ubucucike bw’umuyoboro wa gazi kandi bugaragaza neza ko hakenewe iterambere ry’ejo hazaza rya AEM zifite imbaraga nyinshi kugira ngo twongere ubucucike bw’igihe kirekire bwa MEA kugira ngo AA ikomeze gukorwa ku bucucike bw’umuyoboro wa gazi bukwiriye mu nganda.
Dushingiye ku mikorere ya MEA yacu, twatanze igitekerezo cy’uburyo bwose bwo gukora AA burimo gutanga substrate, electrolysis, neutralization, na separation units (Ishusho y’inyongera ya 37). Hakozwe isesengura ry’imikorere ry’ibanze kugira ngo harebwe niba sisitemu ishoboka mu bukungu hakoreshejwe uburyo bwo gukora electrocatalytic carboxylate ya alkaline electrolyte55. Muri uru rubanza, ibiciro birimo imari, ibikorwa, n’ibikoresho (Ishusho ya 7a n’Ishusho y’inyongera ya 38), kandi inyungu zituruka ku musaruro wa AA na H2. Ibisubizo bya TEA bigaragaza ko mu mikorere yacu (ubucucike bw’ubu 300 mA cm-2, voltage y’uturemangingo 1.76 V, FE 82%), ikiguzi cyose n’inyungu ni US$2429 na US$2564, uko bikurikirana, bigatuma inyungu ingana na US$135 kuri toni ya AA ikorwa (reba Inyandiko y’inyongera ya 9 kugira ngo umenye byinshi).
a Igiciro cyose cy’imikorere ya electrochemical ya AA munsi y’ishingiro ry’ikibazo hamwe na FE ya 82%, ubucucike bw’amashanyarazi bwa 300 mA cm−2, na voltage ya selile ya 1.76 V. Isesengura ry’ubucucike bw’ibiciro bitatu kuri b FE na c ubucucike bw’amashanyarazi. Mu isesengura ry’ubucucike, ibipimo byizwe gusa ni byo byahindutse kandi ibindi bipimo byagumanye hashingiwe kuri moderi ya TEA. d Ingaruka z’ubucucike butandukanye bwa FE n’ubucucike bw’amashanyarazi ku nyungu ya electrosynthesis ya AA n’inyungu hakoreshejwe Ni(OH)2-NS na NiV-LDH-NS, dutekereje ko voltage ya selile igumanye kuri 1.76 V. Amakuru yinjiye kuri a–d atangwa muri dosiye y’amakuru asanzwe.
Dushingiye kuri iyi ngingo, twakomeje gusuzuma ingaruka za FE n'ubucucike bw'amashanyarazi ku nyungu za AA electrosynthesis. Twasanze inyungu zigira ingaruka cyane kuri FE ya AA, kuko kugabanuka kwa FE bituma ikiguzi cy'imikorere kizamuka cyane, bityo ikiguzi rusange kikongera cyane (Ishusho ya 7b). Ku bijyanye n'ubucucike bw'amashanyarazi, ubucucike bw'amashanyarazi buri hejuru (>200 mA cm-2) bufasha kugabanya ikiguzi cy'imari n'ikiguzi cyo kubaka uruganda, ahanini binyuze mu kugabanya agace k'uturemangingo tw'amashanyarazi, bityo bigatera inyungu kwiyongera (Ishusho ya 7c). Ugereranije n'ubucucike bw'amashanyarazi, FE igira ingaruka zikomeye ku nyungu. Mu kugaragaza ingaruka za FE n'ubucucike bw'amashanyarazi ku nyungu, tubona neza akamaro ko kugera kuri FE iri hejuru (>60%) ku bucucike bw'amashanyarazi bujyanye n'inganda (>200 mA cm-2) kugira ngo haboneke inyungu. Bitewe n'agaciro ka FE ka AA kari hejuru, sisitemu yo gusubiza hamwe na NiV-LDH-NS nk'umusemburo iguma ari nziza hagati ya 100–500 mA cm−2 (utudomo twa pentagram; Ishusho ya 7d). Ariko, kuri Ni(OH)2-NS, kugabanya FE ku bucucike bw'umuyoboro w'amashanyarazi (>200 mA cm−2) byatanze umusaruro mubi (uruziga; Ishusho ya 7d), bigaragaza akamaro ka catalysts zifite FE nyinshi ku bucucike bw'umuyoboro w'amashanyarazi mwinshi.
Uretse akamaro k'ibitera imbaraga mu kugabanya ikiguzi cy'imari n'imikorere, isuzuma ryacu rya TEA rigaragaza ko inyungu ishobora kunozwa mu buryo bubiri. Ubwa mbere ni ukugurisha hamwe potassium sulfate (K2SO4) ku isoko nk'umusaruro w'igice cyo gukurura, ariko hashobora kwinjiza amadolari 828/t AA-1 y'Amerika (Inyongera 9). Icya kabiri ni ugutunganya ikoranabuhanga ryo gutunganya, harimo no kongera gukoresha ibikoresho cyangwa guteza imbere ikoranabuhanga ryo gutandukanya AA rihendutse (ubundi buryo bwo gutandukanya AA n'ibice byo gukurura). Uburyo bwo gukurura aside-base bukoreshwa ubu bushobora gutuma ibikoresho bizamuka (bigize igice kinini kuri 85.3%), aho 94% muri byo biterwa na cyclohexanone na KOH ($2069/t AA-1; Ishusho ya 7a), ariko nk'uko byavuzwe haruguru, uburyo buracyafite inyungu muri rusange. Turasaba ko ikiguzi cy'ibikoresho gishobora kugabanuka kurushaho hakoreshejwe uburyo bugezweho bwo kugarura KOH na cyclohexanone itarakira, nka electrodialysis kugira ngo KOH14 igaruke burundu (ikiguzi cyabariwemo $1073/t AA-1 binyuze muri electrodialysis; Inyandiko y'inyongera 9).
Muri make, twageze ku buhanga buhanitse bwa electrolysis ya atome ya aluminiyumu ku bucucike bw'umuvuduko mwinshi w'amashanyarazi binyuze mu kwinjiza V muri nanosheets za Ni(OH)2. Mu rwego rwo hejuru rw'ubushobozi bwa 1.5–1.9 VRHE n'ubucucike bw'umuvuduko mwinshi wa 170 mA cm−2, AA FE kuri NiV-LDH-NS yageze kuri 83–88%, mu gihe OER yagabanijwe neza igera kuri 3%. Impinduka za V zateje imbere kugabanuka kwa Ni2+ kuri Ni3+x no kongera uburyo cyclohexanone ikwirakwira. Amakuru y'igerageza n'ay'imitekerereze agaragaza ko kongera uburyo bwo kongera ubucucike bw'umuvuduko w'amashanyarazi kuri cyclohexanone no guhindura RDS ya COR kuva ku kongera kubaka ijya ku gutakaza umwuka urimo Cα − H scission, mu gihe kongera uburyo cyclohexanone ikwirakwira bigabanya OER. Iterambere rya MEA ryageze ku musaruro wa AA uhoraho ku bucucike bw'umuyoboro w'inganda wa 300 mA cm−2, ubushobozi bwa AA buhanitse bwa 82%, n'umusaruro wa 1536 μmol cm−2 h−1. Ikizamini cy'amasaha 50 cyagaragaje ko NiV-LDH-NS ifite ubucucike bwiza kuko ishobora kugumana AA FE nyinshi muri MEA (> 80% mu masaha 60 kuri 200 mA cm−2; > 70% mu masaha 58 kuri 300 mA cm−2). Ni ngombwa kumenya ko hakenewe guteza imbere AEM zikomeye kugira ngo hagerwe ku bucucike bw'umuyoboro w'amashanyarazi bwiza mu nganda. Byongeye kandi, TEA igaragaza ibyiza by'ubukungu by'ingamba zo gukora AA n'akamaro k'ibikoresho bitanga umusaruro mwinshi hamwe n'ikoranabuhanga rigezweho ryo gutandukanya kugira ngo birusheho kugabanya ikiguzi.