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Iterambere ry'ikoranabuhanga rya hydrogen riri mu mutima w'ubukungu bushingiye ku bidukikije. Nk'ikintu cy'ingenzi kugira ngo haboneke uburyo bwo kubika hydrogen, hakenewe catalysts zikora kandi zihamye zo gutuma hydrogenation ihinduka (de)hydrogenation reaction. Kugeza ubu, aka gace kari gatuwe n'ikoreshwa ry'ibyuma by'agaciro bihenze. Aha, turatanga catalysts nshya ihendutse ishingiye kuri cobalt (Co-SAs/NPs@NC) aho ahantu hakwirakwijwe cyane hahuzwa n'uduce duto tw'icyuma kugira ngo haboneke aside formic dehydrogenation nziza. Hakoreshejwe ibikoresho byiza bya CoN2C2 bitatanye muri atome hamwe n'uduce duto tw'ingufu twa 7-8 nm, hakoreshejwe propylene carbonate nk'umusemburo, habonetse gaze nziza ya 1403.8 ml g-1 h-1, kandi nta gihombo cyabayeho nyuma y'amasaha 5. ibikorwa, bikubye inshuro 15 kurusha Pd/C y'ubucuruzi. Igerageza ry’isuzuma ry’ahantu runaka ryerekana ko, ugereranije na atome imwe y’icyuma na catalysts nanoparticle bifitanye isano, Co-SAs/NPs@NC yongera uburyo HCOO* y’ingenzi ishyirwamo no gukora, bityo bigatera imbere gucika kw’imigozi ya CH. Imibare y’inyigisho igaragaza ko guhuza nanoparticles za cobalt bitera ihinduka ry’igice cya d-band cya atome imwe ya Co mu kibanza gikora, bityo byongera imikoranire hagati ya karuboni O ya HCOO* n’igice cya Co, bityo bigagabanya imbogamizi z’ingufu.
Hydrogen ifatwa nk'ikintu cy'ingenzi gitwara ingufu mu mpinduka z'ingufu ku isi kandi ishobora kuba ingenzi mu gutuma habaho kutagira karuboni ibogama1. Bitewe n'imiterere yayo ifatika nko gutwika no kuba nkeya, kubika no gutwara hidrogen mu buryo bwizewe kandi bunoze ni ibibazo by'ingenzi mu kugera ku bukungu bwa hidrogen2,3,4. Ibikoresho bya hidrogen by'amazi (LOHCs), bibika kandi bikarekura hidrogen binyuze mu bikorwa bya shimi, byatanzwe nk'igisubizo. Ugereranyije na hidrogen ya molekile, ibintu nk'ibi (methanol, toluene, dibenzyltoluene, nibindi) byoroshye kandi byoroshye kubifata5,6,7. Muri LOHC zitandukanye gakondo, aside formic (FA) ifite uburozi buke (LD50: 1.8 g/kg) n'ubushobozi bwa H2 bwa 53 g/L cyangwa 4.4 wt%. Ikigaragara ni uko FA ari yo LOHC yonyine ishobora kubika no kurekura hidrogen mu bihe byoroheje iyo hari catalysts zikwiye, bityo ikaba idasaba ingufu nyinshi zo hanze1,8,9. Mu by’ukuri, hakozwe catalysts nyinshi nziza z’icyuma kugira ngo habeho igabanuka ry’amazi muri aside formike, urugero, catalysts zishingiye kuri palladium zikora inshuro 50-200 kurusha catalysts zihendutse10,11,12. Ariko, iyo utekereje ku giciro cy’ibyuma bikora, urugero, palladium ihenze inshuro zirenga 1000.
Cobalt, Gushakisha ibintu bitandukanye by’icyuma gishingiye ku ikoranabuhanga bikomeje gukurura abashakashatsi benshi mu by’ubumenyi n’inganda13,14,15.
Nubwo catalysts zihendutse zishingiye kuri Mo na Co, hamwe na nanocatalysts zikozwe mu byuma binini/bisanzwe,14,16 byakozwe kugira ngo FA igabanuke, guhagarika kwabyo buhoro buhoro mu gihe cyo gukora ibintu ntibishoboka bitewe n’uko ahantu hakora h’ibyuma, CO2, na H2O hifashishijwe protons cyangwa anions (HCOO-), kwanduza FA, guteranya uduce duto ndetse n’uburozi bwa CO17,18. Twe n’abandi duherutse kugaragaza ko catalysts za atome imwe (SACs) zifite ahantu hatandukanye cyane ha CoIINx nk’ahantu hakora ibintu birushaho kunoza reactivity no resistance ya aside formic dehydrogenation ugereranije na nanoparticles17,19,20,21,22,23,24. Muri ibi bikoresho bya Co-NC, atome za N zikora nk’ahantu hakomeye ho guteza imbere deprotonation ya FA mu gihe cyo kongera ubushobozi bwo kuguma mu miterere binyuze mu guhuza na atome ya Co hagati, mu gihe atome za Co zitanga ahantu ho guterwa H kandi zigateza imbere CH22 scission, 25,26. Ikibabaje ni uko imikorere n'ubudahangarwa by'izi catalysts bikiri kure cyane n'ibigezweho bya noble metal catalysts bihuye kandi bitandukanye (Ishusho ya 1) 13.
Ingufu zirenze urugero ziva mu masoko ashobora kuvugururwa nk'izuba cyangwa umuyaga zishobora gukorwa hakoreshejwe electrolysis y'amazi. Hydrogen ikorwa ishobora kubikwa hakoreshejwe LOHC, amazi afite hydrogenation na dehydrogenation bishobora gusubizwa inyuma. Mu ntambwe yo kugabanya hydrogenation, umusaruro wonyine ni hydrogen, maze amazi atwara agasubizwa uko yari ameze mbere agasubizwamo hydrogen. Hydrogen ishobora gukoreshwa mu ma sitasiyo ya lisansi, bateri, inyubako z'inganda, n'ibindi.
Vuba aha, byatangajwe ko imikorere y’ibanze ya SACs runaka ishobora kwiyongera iyo hari atome zitandukanye z’icyuma cyangwa ahandi hantu hanini hatangwa na nanoparticles (NPs) cyangwa nanoclusters (NCs)27,28. Ibi bitanga amahirwe yo kongera kwinjiza no gukoresha substrate, ndetse no guhindura imiterere n’imiterere y’ikoranabuhanga y’ahantu hanini hanini. Kubwibyo, kwinjiza/gukora substrate bishobora kunozwa, bigatanga imikorere myiza muri rusange ya catalytic29,30. Ibi biduha igitekerezo cyo gukora ibikoresho bikwiye bya catalytic hamwe n’ahantu hanini hanini hanini. Nubwo SACs nziza zagaragaje ubushobozi bukomeye mu buryo butandukanye bwo gukwirakwiza, uruhare rwazo mu kubika hydrogen, nk’uko tubizi, ntirurasobanuka neza. Muri urwo rwego, turatangaza ingamba zikoreshwa kandi zikomeye zo gukora catalysts zishingiye kuri cobalt (Co-SAs/NPs@NCs) zigizwe na nanoparticles zisanzwe hamwe n’ahantu hanini hanini hanini hanini hanini hanini. Co-SAs/NPs@NC ikora neza igaragaza imikorere myiza yo gukuraho aside formic, ikaba ari nziza kurusha catalysts zitari nziza (nka CoNx, atome imwe ya cobalt, cobalt@NC na γ-Mo2N) ndetse na catalysts nziza z'icyuma. Imiterere y'ahantu hamwe n'ibarura rya DFT ry'ako katalysts bikora bigaragaza ko ahantu hatandukanye h'icyuma hakora nk'ahantu hakora, kandi utwuma duto tw'ubu buvumbuzi twongera urwego rwa d-band rwa atomes za Co, bigatera imbere mu kwinjiza no gukora HCOO*, bityo bigabanura ingufu z'ingaruka.
Zeolite imidazolate frameworks (ZIFs) ni ibintu bibanza bifite imiterere itatu bitanga catalysts ku bikoresho bya karubone birimo azote (catalysts z'icyuma-NC) kugira ngo bishyigikire ubwoko butandukanye bw'ibyuma37,38. Kubwibyo, Co(NO3)2 na Zn(NO3)2 bihurira hamwe na 2-methylimidazole muri methanol kugira ngo bikore complexes z'icyuma zijyanye nabyo mu musaruro. Nyuma yo gukurura no kumisha, CoZn-ZIF yapiswe ku bushyuhe butandukanye (750–950 °C) mu kirere cya 6% H2 na 94% Ar. Nkuko bigaragara ku ishusho iri hepfo, ibikoresho bivamo bifite imiterere itandukanye y'ahantu bikora kandi byitwa Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 (Ishusho ya 2a). ). Ibyagaragaye mu bushakashatsi ku ntambwe zimwe na zimwe z'ingenzi mu gikorwa cyo gusimbuza birambuye ku Ishusho ya 1 na 2. C1-C3. Hakozwe ihinduka ry’ubushyuhe bwa X-ray diffraction (VTXRD) kugira ngo hagenzurwe imihindagurikire y’ingufu zikomoka ku bushyuhe. Nyuma y’uko ubushyuhe bwa pyrolysis bugeze kuri 650 °C, imiterere ya XRD irahinduka cyane bitewe no gusenyuka kw’imiterere ya kristale ya ZIF (Ishusho ya S4) 39. Uko ubushyuhe bugenda bwiyongera, imisozi ibiri migari igaragara mu miterere ya XRD ya Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 kuri 20–30 ° na 40–50 °, bigaragaza uburebure bwa karuboni idafite imvange (Ishusho ya C5). 40. Ni ngombwa kumenya ko imisozi itatu gusa ari yo yagaragaye kuri 44.2 °, 51.5 ° na 75.8 °, igizwe na kobalti y’icyuma (JCPDS #15-0806), na 26.2 °, igizwe na karuboni ya grafiti (JCPDS # 41-1487). Imiterere ya X-ray ya Co-SAs/NPs@NC-950 igaragaza ko hari uduce duto twa cobalt twashyizwemo graphite kuri catalyst41,42,43,44. Imiterere ya Raman igaragaza ko Co-SAs/NPs@NC-950 isa nkaho ifite imisozi miremire ya D na G ikomeye kandi ntoya kurusha izindi ngero, bigaragaza ko ifite urwego rwo hejuru rwa graphitization (Ishusho S6). Byongeye kandi, Co-SAs/NPs@NC-950 igaragaza ubuso bwa Brunner-Emmett-Taylor (BET) n'ingano y'umuyoboro (1261 m2 g-1 na 0.37 cm3 g-1) kurusha izindi ngero kandi ZIF nyinshi ni ibikoresho bya NC derivatives. (Ishusho S7 n'Imbonerahamwe S1). Isesengura ry’ingufu za atomiki (AAS) rigaragaza ko ingano ya kobalti ya Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@ ari 2.69 wt%, 2.74 % wt. na 2.73% wt. NC-750 uko bikurikirana (Imbonerahamwe S2). Ingano ya Zn ya Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 yiyongera buhoro buhoro, ibi bikaba biterwa no kwiyongera kw’igabanuka n’ihindagurika ry’ibice bya Zn. Ubwiyongere bw’ubushyuhe bwa pyrolysis (Zn, ubushyuhe bushyuha = 907 °C) 45.46. Isesengura ry’ibintu (EA) ryagaragaje ko ijanisha rya N rigabanuka uko ubushyuhe bwa pyrolysis bwiyongera, kandi ingano ya O2 nyinshi ishobora guterwa no kwinjiza O2 mu mwuka. (Imbonerahamwe S3). Ku gipimo runaka cya kobalti, uduce duto n'uduce twihariye twa coatom bihura, bigatuma habaho kwiyongera gukomeye kw'imikorere ya catalyst, nk'uko byavuzwe hano hepfo.
Ishusho y'icyitegererezo cy'ikorwa rya Co-SA/NPs@NC-T, aho T ari ubushyuhe bwa pyrolysis (°C). b Ishusho ya TEM. c Ishusho ya Co-SAs/NPs@NC-950 AC-HAADF-STEM. Atome za Co ku giti cyazo zirangwa n'uruziga rutukura. d Icyitegererezo cya EDS Co-SA/NPs@NC-950.
Ikigaragara ni uko mikorosikopi ya elegitoroniki yoherezwa (TEM) yagaragaje ko hari utunyangingo twa kobalti (NPs) dutandukanye dufite ingano mpuzandengo ya 7.5 ± 1.7 nm gusa muri Co-SA/NPs@NC-950 (Ishusho ya 2 b na S8). Utu tunyangingo dushyirwamo karubone isa na grafiti irimo azote. Intera iri hagati ya 0.361 na 0.201 nm ihuye na karubone ya grafiti (002) na Co (111) y'icyuma. Byongeye kandi, mikorosikopi ya elegitoroniki yoherezwamo ya annular dark-field scanning (AC-HAADF-STEM) yagaragaje ko Co NPs muri Co-SAs/NPs@NC-950 zari zikikijwe na cobalti nyinshi ya atome (Ishusho ya 2c). Ariko, ni atome za kobalti zitatanye muri atome gusa zabonetse ku nkunga y'izindi ngero ebyiri (Ishusho ya S9). Ishusho ya HAADF-STEM yo gukoresha ingufu (EDS) igaragaza uburyo C, N, Co n'ibice bya Co NP byatandukanyijwe muri Co-SAs/NPs@NC-950 bikwirakwizwa mu buryo bumwe (Ishusho ya 2d). Ibi byose bigaragaza ko ibice bya Co na nanoparticles byashyizwe muri karuboni imeze nka grafiti ya N bifatanye neza na substrates za NC muri Co-SAs/NPs@NC-950, mu gihe ibice bya metali byashyizwemo gusa.
Imiterere ya valence n'imiterere ya chimique by'ibikoresho byabonetse byizweho hakoreshejwe X-ray photoelectron spectroscopy (XPS). XPS spectra y'ibinyabutabire bitatu yagaragaje ko hari ibintu Co, N, C na O, ariko Zn yari ihari gusa muri Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 (Ishusho ya 2). ). C10). Uko ubushyuhe bwa pyrolysis bwiyongera, igipimo cya azote yose kigabanuka uko ubwoko bwa azote buhinduka budahindagurika kandi bugahinduka imyuka ya NH3 na NOx ku bushyuhe bwinshi (Imbonerahamwe ya S4) 47. Bityo, igipimo cya karuboni cyose cyariyongereye buhoro buhoro kuva kuri Co-SAs/NPs@NC-750 kugera kuri Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-950 (Ishusho ya S11 na S12). Icyitegererezo cya pyrolysis ku bushyuhe bwinshi gifite igipimo gito cya atome za azote, bivuze ko ingano y'ibinyabutabire bya NC muri Co-SAs/NPs@NC-950 igomba kuba munsi y'iyo mu zindi ngero. Ibi bituma uduce twa kobalti duhinduka cyane. Umubumbe wa O 1s ugaragaza uduce tubiri twa C=O (531.6 eV) na C–O (533.5 eV), uko bikurikirana (Ishusho S13) 48. Nkuko bigaragara ku Ishusho ya 2a, umubumbe wa N 1s ushobora gukemurwa mu duce tune twihariye twa pyridine azote N (398.4 eV), pyrrole N (401.1 eV), graphite N (402.3 eV) na Co-N (399.2 eV). Imiyoboro ya Co-N iboneka mu ngero zose uko ari eshatu, bigaragaza ko atome zimwe na zimwe za N zihujwe n’ahantu hatandukanye, ariko imiterere itandukanye cyane49. Gukoresha ubushyuhe bwinshi bwa pyrolysis bishobora kugabanya cyane ingano y’ubwoko bwa Co-N kuva kuri 43.7% muri Co-SA/NPs@NC-750 kugera kuri 27.0% muri Co-SAs/NPs@NC-850 na Co 17.6%@ NC-950. muri -CA/NPs, bihuye n'ubwiyongere bw'ibipimo bya C (Ishusho ya 3a), bigaragaza ko umubare wabo wa Co-N ushobora guhinduka ugasimburwa igice na atome za C50. Ishusho ya Zn 2p igaragaza ko iki kintu kiri mu buryo bwa Zn2+. (Ishusho S14) 51. Ishusho ya Co2p igaragaza imisozi ibiri igaragara kuri 780.8 na 796.1 eV, iterwa na Co 2p3/2 na Co 2p1/2, uko bikurikirana (Ishusho ya 3b). Ugereranyije na Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750, umusozi wa Co-N muri Co-SAs/NPs@NC-950 wimuriwe ku ruhande rwiza, bigaragaza ko atome imwe ya Co-N ku buso bwa -SAs/NPs@NC-950 ifite urugero rwo hejuru rwo kugabanuka kwa electron, bigatuma habaho imiterere yo hejuru ya oxidation. Ni ngombwa kumenya ko Co-SAs/NPs@NC-950 ari yo yonyine yagaragaje ko cobalt (Co0) ifite intege nke kuri 778.5 eV, ibi bikaba bigaragaza ko hari uduce duto duturuka ku guteranya kobalt SA mu bushyuhe bwinshi.
a N 1s na b Co 2p spectra ya Co-SA/NPs@NC-T. c XANES na d FT-EXAFS spectra ya Co-K-edge ya Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750. e WT-EXAFS contour plots ya Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850, na Co-SAs/NPs@NC-750. f FT-EXAFS fitting curve kuri Co-SA/NPs@NC-950.
Nyuma yaho, uburyo bwo gupima X-ray absorption spectroscopy (XAS) bwakoreshejwe mu gusesengura imiterere y'ikoranabuhanga n'ibidukikije byo guhuza ubwoko bwa Co mu gipimo cyateguwe. Cobalt valence states muri Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 Imiterere y'inkombe yagaragajwe n'uburyo bwo gupima X-ray hafi y'ubutaka bwa Co-K edge (XANES) spectrum. Nkuko bigaragara ku Ishusho ya 3c, gupima hafi y'inkombe z'ibipimo bitatu biri hagati ya Co na CoO foils, bigaragaza ko imiterere ya valence y'ubwoko bwa Co iri hagati ya 0 na +253. Byongeye kandi, hagaragaye impinduka ku ngufu nke kuva kuri Co-SAs/NPs@NC-950 kugera kuri Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750, bigaragaza ko Co-SAs/NPs@NC-750 ifite imiterere yo hasi ya oxidation. Dukurikije ibisubizo byo guhuza umurongo, imiterere ya Co valence ya Co-SAs/NPs@NC-950 igereranywa ko ari +0.642, iri munsi y’imiterere ya Co valence ya Co-SAs/NPs@NC-850 (+1.376). Co-SA/NP @NC-750 (+1.402). Ibi bisubizo bigaragaza ko imiterere mpuzandengo ya oxidation y’uduce twa cobalt muri Co-SAs/NPs@NC-950 yagabanutse cyane, ibi bikaba bihuye n’ibisubizo bya XRD na HADF-STEM kandi bishobora gusobanurwa no kuba hamwe kwa cobalt nanoparticles na cobalt imwe. Atome za Co 41. Imiterere mito ya X-ray ihinduka (FT-EXAFS) ya Co K-edge igaragaza ko uburebure bw'umusozo kuri 1.32 Å ari ubw'igishishwa cya Co-N/Co-C, mu gihe inzira yo gukwirakwira ya Co-Co y'icyuma iri kuri 2.18 gusa muri Co-SAs Å iboneka muri /NPs@NC-950 (Ishusho ya 3d). Byongeye kandi, igishushanyo cya wavelet transform (WT) kigaragaza imbaraga ntarengwa kuri 6.7 Å-1 iterwa na Co-N/Co-C, mu gihe Co-SAs/NPs@NC-950 gusa ari yo igaragaza imbaraga ntarengwa iterwa na 8.8. Ubundi mbaraga ntarengwa ni kuri Å−1 ku mugozi wa Co-Co (Ishusho ya 3e). Byongeye kandi, isesengura rya EXAFS ryakozwe n'umukodesha ryagaragaje ko ku bushyuhe bwa pyrolysis bwa 750, 850 na 950 °C, imibare ya Co-N yari 3.8, 3.2 na 2.3, uko bikurikirana, naho imibare ya Co-C yari 0. 0.9 na 1.8 (Ishusho ya 3f, S15 na Imbonerahamwe ya S1). By'umwihariko, ibisubizo biheruka bishobora guterwa no kuba hari ibice bya CoN2C2 na nanoparticles bitatanye muri atome muri Co-SAs/NPs@NC-950. Mu buryo bunyuranye, muri Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750, ibice bya CoN3C na CoN4 ni byo byonyine biboneka. Biragaragara ko iyo ubushyuhe bwa pyrolysis bwiyongera, atome za N mu gice cya CoN4 zigenda zisimburwa buhoro buhoro na atome za C, maze cobalt CA zigaterana zigakora nanoparticles.
Imiterere y’ibisubizo byizwe mbere yakoreshejwe mu kwiga ingaruka z’imiterere y’ibipimo byo gutegura ku miterere y’ibikoresho bitandukanye (Ishusho S16)17,49. Nkuko bigaragara ku Ishusho ya 4 a, imikorere ya Co-SAs/NPs@NC-950 iri hejuru cyane kurusha iya Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750. Ikigaragara ni uko ingero eshatu za Co zateguwe zagaragaje imikorere myiza ugereranije na catalysts zisanzwe z’ubucuruzi (Pd/C na Pt/C). Byongeye kandi, ingero za Zn-ZIF-8 na Zn-NC ntizagize uruhare mu gukuraho aside formic, bigaragaza ko uduce twa Zn tudakora, ariko ingaruka zabyo ku gikorwa ni nke cyane. Byongeye kandi, imikorere ya Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 yakozwe kuri pyrolysis ya kabiri kuri 950°C mu gihe cy’isaha 1, ariko yari iri hasi ugereranyije n’iya Co-SAs/NPs@NC-750. @NC-950 (Ishusho S17). Imiterere y’ibi bikoresho yagaragaje ko hari uduce duto twa Co mu bipimo byasubiwemo pyrolyze, ariko ubuso buke bwihariye hamwe no kutagira karuboni isa na grafiti byatumye habaho ibikorwa bike ugereranije na Co-SAs/NPs@NC-950 (Ishusho S18–S20). Ibikorwa by’ibipimo bifite ingano itandukanye ya Co precursor nabyo byaragereranyijwe, aho ibikorwa byinshi byagaragajwe ku kwiyongera kwa mol 3.5 (Imbonerahamwe S6 n’Ishusho S21). Biragaragara ko ikorwa ry’ibice bitandukanye by’icyuma riterwa n’ingano ya hydrogen mu kirere cya pyrolysis n’igihe cya pyrolysis. Kubwibyo, ibindi bikoresho bya Co-SAs/NPs@NC-950 byapimwe kugira ngo harebwe imikorere ya aside formic. Ibikoresho byose byagaragaje imikorere iri hagati kugeza ku myiza cyane; icyakora, nta na kimwe muri byo cyari cyiza kurusha Co-SAs/NPs@NC-950 (Ishusho S22 na S23). Imiterere y'imiterere y'ibikoresho yagaragaje ko uko igihe cyo gukora pyrolysis kigenda cyiyongera, ingano y'imyanya ya Co-N igenda igabanuka buhoro buhoro bitewe no kwishyira hamwe kwa atome z'icyuma mu tunyangingo duto, ibi bikaba bisobanura itandukaniro ry'imikorere hagati y'ibipimo bifite igihe cyo gukora pyrolysis kingana na 100-2000. Itandukaniro riri hagati y'amasaha 0.5, isaha 1, n'amasaha 2 (Ishusho S24–S28 n'Imbonerahamwe S7).
Imbonerahamwe y'ingano ya gazi ugereranije n'igihe cyabonetse mu gihe cyo gukuraho amazi mu matsinda y'ibikomoka kuri lisansi hakoreshejwe catalysts zitandukanye. Imiterere y'ingaruka: FA (10 mmol, 377 μl), catalysts (30 mg), PC (6 ml), Tback: 110 °C, Tactical: 98 °C, ibice 4 b Co-SAs/NPs@NC-950 (30 mg), solvents zitandukanye. c Kugereranya igipimo cy'ihindagurika rya gazi mu solvents zitandukanye mu solvents organic kuri 85–110 °C. d Co-SA/NPs@NC-950 igerageza ryo kongera gukoresha. Imiterere y'ingaruka: FA (10 mmol, 377 µl), Co-SAs/NPs@NC-950 (30 mg), solvent (6 ml), Tback: 110 °C, Tactical: 98 °C, buri ruziga rw'ingaruka rumara isaha imwe. Uduce tw'amakosa tugaragaza ihinduka risanzwe ryabazwe mu bizamini bitatu bikora.
Muri rusange, ubushobozi bwa catalysts za FA dehydrogenation bushingira cyane ku miterere y’imyakura, cyane cyane solvent ikoreshwa8,49. Mu gihe cyo gukoresha amazi nk’umusemburo, Co-SAs/NPs@NC-950 yagaragaje igipimo cyo hejuru cy’imyakura, ariko habayeho guhagarika, bishoboka ko byatewe na protons cyangwa H2O18 byinjira mu myanya ikora. Igeragezwa rya catalysts mu bintu bisukura organic nka 1,4-dioxane (DXA), n-butyl acetate (BAC), toluene (PhMe), triglyceme na cyclohexanone (CYC) nabyo ntibyagaragaje iterambere, no muri propylene carbonate (PC)) (Ishusho ya 4b n'Imbonerahamwe ya S8). Mu buryo nk'ubwo, inyongera nka triethylamine (NEt3) cyangwa sodium formate (HCCONA) nta ngaruka nziza byagize ku mikorere ya catalysts (Ishusho ya S29). Mu gihe cy’uburyo bwiza bwo gukora ibizamini, umusaruro wa gazi wageze kuri 1403.8 mL g−1 h−1 (Ishusho ya S30), wari hejuru cyane ugereranije na katalysts zose za Co zavuzwe mbere (harimo na SAC17, 23, 24). Mu bushakashatsi butandukanye, hatabariwemo ingaruka mu mazi no mu nyongeramusaruro za formate, habonetse uburyo bwo guhitamo kugeza kuri 99.96% bwo gutakaza amazi no kubura amazi (Imbonerahamwe ya S9). Ingufu zo gukora zabazwe ni 88.4 kJ/mol, zingana n’ingufu zo gukora za katalysts z’ibyuma byiza (Ishusho ya S31 n’Imbonerahamwe ya S10).
Byongeye kandi, twagereranije izindi catalysts zitandukanye zo gukuraho aside formic mu bihe bisa (Ishusho ya 4c, imbonerahamwe ya S11 na S12). Nkuko bigaragara ku Ishusho ya 3c, igipimo cy’umusaruro wa gaze wa Co-SAs/NPs@NC-950 kirenze icya catalysts nyinshi zizwi cyane kandi kiri hejuru inshuro 15 na 15 kurusha icya 5% Pd/C na 5% Pd/C, uko bikurikirana. % Pt/C catalyst.
Ikintu cy'ingenzi mu ikoreshwa ry’ibintu bitera imbaraga (de) hydrogenation ni ugukomera kwabyo. Kubwibyo, hakozwe igerageza ryo kongera gukoresha Co-SAs/NPs@NC-950. Nkuko bigaragara ku Ishusho ya 4 d, igikorwa cya mbere n’uburyo ibintu byatoranijwe byakomeje guhinduka mu gihe cy’amasaha atanu yikurikiranya (reba kandi Imbonerahamwe ya S13). Ibizamini by’igihe kirekire byakozwe kandi umusaruro wa gazi wiyongereye ku murongo mu masaha 72 (Ishusho ya S32). Ingano ya cobalt ya Co-SA/NPs@NC-950 yakoreshejwe yari 2.5 wt%, byari hafi cyane y’iya catalyst nshya, bigaragaza ko nta gusohoka kwa cobalt kugaragara kwabayeho (Imbonerahamwe ya S14). Nta mpinduka igaragara y’ibara cyangwa kwegeranya ibice by’icyuma byagaragaye mbere na nyuma y’uko bikorwa (Ishusho ya S33). AC-HAADF-STEM na EDS by’ibikoresho byakoreshejwe mu igerageza ry’igihe kirekire byagaragaje ko ahantu hakwirakwizwa atome haguma kandi ko nta mpinduka zikomeye mu miterere yazo (Ishusho ya S34 na S35). Impera ziranga Co0 na Co-N ziracyariho muri XPS, bigaragaza ko Co NPs n'ahantu hatandukanye h'ibyuma bihurira, ibi kandi byemeza ko Co-SAs/NPs@NC-950 catalyst ihamye (Ishusho S36).
Kugira ngo hamenyekane ahantu hakora cyane hatuma habaho gutakaza aside formike, hateguwe ibikoresho byatoranijwe bifite ikigo kimwe cy’icyuma (CoN2C2) cyangwa Co NP hashingiwe ku bushakashatsi bwabanje17. Urutonde rw’ibikorwa byo gutakaza aside formike byagaragaye mu bihe bimwe ni Co-SAs/NPs@NC-950 > Co SA > Co NP (Imbonerahamwe S15), bigaragaza ko ahantu hatandukanye muri atome ya CoN2C2 hakora cyane kurusha NPs. Ikinetiki y’ibisubizo igaragaza ko impinduka ya hydrogen ikurikira ikinetiki y’ibisubizo bya mbere, ariko imiterere y’imirongo myinshi ku bikubiye muri cobalt itandukanye ntabwo ari imwe, bigaragaza ko ikinetiki idashingiye gusa kuri aside formike, ahubwo no ku hantu hakora (Ishusho ya 2). C37). Ubundi bushakashatsi bwa kinetiki bwagaragaje ko, bitewe n’uko nta misongero y’icyuma cya cobalt mu isesengura rya X-ray diffraction, uburyo ikinetiki y’ibisubizo mu bijyanye n’ibikubiye muri cobalt byagaragaye ko ari 1.02 ku rugero rwo hasi (munsi ya 2.5%), bigaragaza ko hafi ya hose hakwirakwizwa kimwe hagati ya monoatomic cobalt. ahantu hakora (ishusho ya S38 na S39). Iyo ingano y'uduce twa Co igeze kuri 2.7%, r yiyongera mu buryo butunguranye, bigaragaza ko uduce duto dukorana neza na atome ku giti cyatwo kugira ngo tugire imikorere myinshi. Uko ingano y'uduce twa Co igenda yiyongera, umugozi uba utari umurongo, bijyana no kwiyongera k'umubare w'uduce duto no kugabanuka kw'imyanya ya monatome. Bityo, imikorere myiza ya LC dehydrogenation ya Co-SA/NPs@NC-950 ituruka ku myitwarire y'ubufatanye y'ahantu hakozwe ibyuma na nanoparticles ku giti cyatwo.
Hakozwe ubushakashatsi bwimbitse hakoreshejwe isuzuma rya Fourier (in situ DRIFT) kugira ngo hamenyekane uburyo bwo guhuza ibikorwa muri icyo gikorwa. Nyuma yo gushyushya ingero ku bushyuhe butandukanye bw'ibikorwa nyuma yo kongeramo aside formike, hagaragaye amatsinda abiri y'imirongo (Ishusho ya 5a). Imisongero itatu iranga HCOOH* igaragara kuri 1089, 1217 na 1790 cm-1, iterwa no guhindagura kwa CH π (CH) hanze y'indege, guhindagura kwa CO ν (CO) na guhindagura kwa C=O ν (C=O) inyuma y'ikirere, 54, 55 uko bikurikirana. Indi misongero iri kuri 1363 na 1592 cm-1 ihuye n'imitingito ya OCO νs (OCO) na OCO stretching vibration νas (OCO)33.56 HCOO* uko bikurikirana. Uko ibikorwa bigenda birushaho kugenda, misongero ya HCOOH* na HCOO* igenda igabanuka buhoro buhoro. Muri rusange, gusenya aside formike bikubiyemo intambwe eshatu z'ingenzi: (I) kwinjiza aside formike ahantu hakora, (II) gukuraho H binyuze mu nzira ya formike cyangwa carboxylate, na (III) guhuza H ebyiri zivanze kugira ngo zikore hydrogen. HCOO* na COOH* ni byo bintu by'ingenzi mu kugena inzira za formike cyangwa carboxylate, uko bikurikirana57. Muri sisitemu yacu ya catalytic, niho hagaragaye gusa umusozi wa HCOO*, bigaragaza ko gusenya aside formike bibaho gusa binyuze mu nzira ya formike58. Ibitekerezo nk'ibyo byakozwe ku bushyuhe buri hasi bwa 78 °C na 88 °C (igishushanyo cya S40).
Imiterere ya DRIFT spectra ya HCOOH dehydrogenation kuri Co-SAs/NPs@NC-950 na b Co SAs. Iyi nkuru igaragaza igihe cyo gukora ibikorwa. c Imiterere y'ingano ya gaze yabonetse hakoreshejwe reagents zitandukanye zo gushyira ibirango bya isotope. d Amakuru y'ingaruka za isotope ya Kinetic.
Igerageza rya DRIFT nk'iryo ryakozwe ku bikoresho bifitanye isano Co NP na Co SA kugira ngo bige ingaruka zo guhuza muri Co-SA/NPs@NC-950 (Ishusho ya 5 b na S41). Ibikoresho byombi bigaragaza imiterere isa, ariko imiterere y'impande za HCOOH* na HCOO* yahindutse gato, bigaragaza ko kwinjizwa kwa Co NPs bihindura imiterere y'ikoranabuhanga y'ikigo cy'impande za atome. Ingano y'impande ya νas(OCO) igaragara muri Co-SAs/NPs@NC-950 na Co SA ariko ntabwo igaragara muri Co NPs, byerekana kandi ko igice cyo hagati cyakozwe iyo hongewemo aside formike ari monodentate formike aside perpendicular ku buso bw'umunyu. kandi gishyirwa kuri SA nk'ahantu 59 hakora. Ni ngombwa kumenya ko hagaragaye ukwiyongera gukomeye mu mihindagurikire y'impande π(CH) na ν(C = O) byagaragaye, bigaragara ko byatumye HCOOH* ihinduka kandi byoroshya uburyo bwo kuyikora. Kubera iyo mpamvu, imiterere y’impeshyi za HCOOH* na HCOO* muri Co-SAs/NPs@NC hafi ya yose yazimye nyuma y’iminota 2 y’inyito, ikaba yihuta kurusha iya monometallic (iminota 6) na nanoparticle-based catalysts (iminota 12). Ibi byose byemeza ko nanoparticle doping yongera uburyo intermediates ziyongeramo no gukora, bityo ikihutisha uburyo bwavuzwe haruguru.
Kugira ngo harusheho gusesengura inzira y’ibizamini no kumenya intambwe yo kugena igipimo (RDS), ingaruka za KIE zakozwe imbere ya Co-SAs/NPs@NC-950. Aha, isotope zitandukanye za aside formic nka HCOOH, HCOOD, DCOOH na DCOOD zikoreshwa mu bushakashatsi bwa KIE. Nkuko bigaragara ku Ishusho ya 5c, igipimo cyo gutakaza hydrogenation kigabanuka mu buryo bukurikira: HCOOH > HCOOD > DCOOH > DCOOD. Byongeye kandi, agaciro kabazwe ka KHCOOH/KHCOOD, KHCOOH/KDCOOH, KHCOOD/KDCOOD na KDCOOH/KDCOOD kari 1.14, 1.71, 2.16 na 1.44, uko bikurikirana (Ishusho ya 5d). Bityo, gucika kw'imigozi ya CH muri HCOO* bigaragaza agaciro ka kH/kD ​​>1.5, bigaragaza ingaruka zikomeye za kinetic60,61, kandi bisa nkaho bigaragaza RDS ya HCOOH dehydrogenation kuri Co-SAs/NPs@NC-950.
Byongeye kandi, hakozwe imibare ya DFT kugira ngo hubahirizwe ingaruka z'uduce duto twa nano ku bikorwa bya Co-SA. Imiterere ya Co-SAs/NPs@NC na Co-SA yakozwe hashingiwe ku bushakashatsi bwagaragajwe n'imirimo yabanje (Ishusho ya 6a na S42)52,62. Nyuma yo kunoza imiterere y'ishusho, uduce duto twa Co6 (CoN2C2) dufatanye n'utunyangingo twa monoatomike twagaragaye, maze uburebure bwa Co-C na Co-N muri Co-SA/NPs@NC bwagenwe kuba 1.87 Å na 1.90 Å, uko bikurikirana. , ibi bikaba bihuye n'ibyavuye muri XAFS. Ubucucike bw'ibice bibazwe (PDOS) bwerekana ko atome imwe y'icyuma cya Co na nanoparticle composite (Co-SAs/NPs@NC) bigaragaza hybridization iri hejuru hafi y'urwego rwa Fermi ugereranije na CoN2C2, bigatuma HCOOH iba nziza cyane (Ishusho ya 6b na S43). Ibice bihuza na d-band bya Co-SAs/NPs@NC na Co-SA byabazwe ko ari -0.67 eV na -0.80 eV, muri byo hakaba harimo ukwiyongera kwa Co-SAs/NPs@NC kwari 0.13 eV, byagize uruhare mu gutuma nyuma yo gushyirwaho kwa NP, hagaragara ukwiyongera kw'uduce twa HCOO* bitewe n'imiterere ya elegitoroniki ya CoN2C2. Itandukaniro mu bucucike bw'amashanyarazi rigaragaza igicu kinini cya elegitoroniki gikikije block ya CoN2C2 na nanoparticle, bigaragaza ko hari imikoranire ikomeye hagati yabyo bitewe no guhererekanya elegitoroniki. Hamwe n'isesengura rya Bader charge, byagaragaye ko Co-SA itatanye muri atome yatakaje 1.064e muri Co-SA/NPs@NC na 0.796e muri Co SA (Ishusho S44). Ibi bisubizo bigaragaza ko guhuza nanoparticles bituma electron zigabanuka ku duce twa Co, bigatuma Co valence yiyongera, ibi bikaba bihuye n'ibyavuye muri XPS (Ishusho ya 6c). Imiterere y'imikoranire ya Co-O yo kwinjiza HCOO kuri Co-SAs/NPs@NC na Co SA yasesenguwe hakorwa isesengura rya crystalline orbital Hamiltonian group (COHP)63. Nkuko bigaragara ku Ishusho ya 6 d, agaciro ka -COHP kari hasi n'akari hasi gahuye n'imimerere yo kurwanya ubuhuza n'imimerere yo gufatana, uko bikurikirana. Ingufu z'ubuhuza za Co-O ziterwa na HCOO (Co-carbonylOH HCOO*) zapimwe hahujwe agaciro ka -COHP, kari 3.51 na 3.38 kuri Co-SAs/NPs@NC na Co-SA, uko bikurikirana. Kwinjiza HCOOH nabyo byagaragaje ibisubizo bisa: kwiyongera kw'agaciro k'ingenzi ka -COHP nyuma yo gukoresha nanoparticle doping byagaragaje ukwiyongera kw'ubuhuza bwa Co-O, bityo bigatera imbere gukora kwa HCOO na HCOOH (Ishusho ya S45).
Imiterere ya Co-SA/NPs@NC-950. b PDOS Co-SA/NP@NC-950 na Co SA. c Isosurface ya 3D y'itandukaniro mu bucucike bwa charge bwa HCOOH adsorption kuri Co-SA/NPs@NC-950 na Co-SA. (d) pCOHP ya Co-O bonds yatewe na HCOO kuri Co-SA/NPs@NC-950 (ibumoso) na Co-SA (iburyo). e Inzira yo gusubiza HCOOH dehydrogenation kuri Co-SA/NPs@NC-950 na Co-SA.
Kugira ngo dusobanukirwe neza imikorere myiza ya Co-SA/NPs@NC yo gukuraho amazi mu kirere, inzira n'ingufu byashyizweho. By'umwihariko, gukuraho amazi mu kirere bya FA bikubiyemo intambwe eshanu, harimo guhindura HCOOH muri HCOOH*, HCOOH* muri HCOO* + H*, HCOO* + H* muri 2H* + CO2*, 2H* + CO2* muri 2H* + CO2, na 2H* muri H2 (Ishusho ya 6e). Ingufu zo kwinjiza aside formic ku buso bwa catalyst binyuze muri ogisijeni karubokisilike ni nkeya kurusha binyuze muri ogisijeni hidroksili (Ishusho ya S46 na S47). Nyuma yaho, bitewe n'ingufu nke, adsorbate ikunze gucamo OH bond breakavage kugira ngo ikore HCOO* aho gucamo CH bond kugira ngo ikore COOH*. Muri icyo gihe, HCOO* ikoresha monodentate adsorption, ituma imigozi icika no gushyiraho CO2 na H2. Ibi bisubizo bihuye n’uko hari uburebure bwa νas (OCO) muri DRIFT, bigaragaza ko kwangirika kwa FA bibaho binyuze mu nzira ya formate mu bushakashatsi bwacu. Ni ngombwa kumenya ko dukurikije ibipimo bya KIE, kwitandukanya kwa CH bifite imbogamizi nyinshi cyane ku ngufu za reaction kurusha izindi ntambwe za reaction kandi bigaragaza RDS. Ingufu za sisitemu ya Co-SAs/NPs@NC catalyst ni 0.86 eV munsi y’iya Co-SA (1.2 eV), ibyo bikaba birushaho kunoza imikorere rusange ya dehydrogenation. Ikigaragara ni uko kuba hari nanoparticles bigenga imiterere ya elegitoroniki y’ahantu hatandukanye ha atome, ibyo bikaba byongera uburyo bwo kwinjiza no gukora ibintu hagati, bityo bigabanura imbogamizi za reaction kandi bigateza imbere ikorwa rya hydrogen.
Muri make, twerekanye bwa mbere ko imikorere ya catalytic ya catalysts ikorwa na hydrogen ishobora kunozwa cyane hakoreshejwe ibikoresho bifite centers monometallic centers hamwe na nanoparticles nto. Iki gitekerezo cyemejwe no gukora catalysts imwe-atome metal catalysts yahinduwe na nanoparticles (Co-SAs/NPs@NC), ndetse n'ibindi bikoresho bifitanye isano bifite centers imwe-metal gusa (CoN2C2) cyangwa Co NPs. Ibikoresho byose byateguwe hakoreshejwe uburyo bworoshye bwa pyrolysis. Isesengura ry'imiterere ryerekana ko catalysts nziza (Co-SAs/NPs@NC-950) igizwe na atome za CoN2C2 zitatanye hamwe na nanoparticles nto (7-8 nm) zirimo azote na graphite-like carbon. Ifite umusaruro mwiza wa gaze kugeza kuri 1403.8 ml g-1 h-1 (H2:CO2 = 1.01:1), H2 na CO selectivity ya 99.96% kandi ishobora gukomeza gukora iminsi myinshi. Igikorwa cy'iyi catalyst kirenze imikorere ya catalysts zimwe na zimwe za Co SA na Pd/C inshuro 4 na 15, uko bikurikirana. Igerageza rya DRIFT ryerekana ko ugereranije na Co-SA, Co-SAs/NPs@NC-950 igaragaza ko HCOO** irushaho kuba nziza, ikaba ari ingenzi ku nzira ya formate, kandi uduce duto twa dopant dushobora guteza imbere HCOO* gukora no kwihutisha C–H. Gucika kw'imigozi byagaragaye ko ari RDS. Imibare y'inyigisho igaragaza ko CoNP doping yongera centre d-band ya atome imwe ya Co2 ku kigero cya 0.13 eV binyuze mu gukorana, yongera uburyo HCOOH* na HCOO* intermediates zikoreshwa, bityo bigabanura imbogamizi yo gukora kuva kuri 1.20 eV kuri CoSA ikagera kuri 0 .86 eV. Ashinzwe imikorere myiza cyane.
Muri rusange, ubu bushakashatsi butanga ibitekerezo byo gushushanya katalyst nshya z’icyuma zikoresha atome imwe kandi buteza imbere ubumenyi bw’uburyo bwo kunoza imikorere ya katalyst binyuze mu ngaruka z’imikorere y’ibyuma bifite ingano zitandukanye. Twizera ko ubu buryo bushobora kwaguka mu buryo bworoshye no mu zindi nzira nyinshi za katalyst.
Co(NO3)2 6H2O (AR, 99%), Zn(NO3)2 6H2O (AR, 99%), 2-methylimidazole (98%), methanol (99.5%), propylene karubone (PC, 99%) ethanol (AR, 99.7%) yaguzwe muri McLean, mu Bushinwa. Acide formic (HCOOH, 98%) yaguzwe muri Rhawn, mu Bushinwa. Ibikoresho byose byakoreshejwe mu buryo butaziguye nta gusukurwa kwinshi, kandi amazi meza cyane yateguwe hakoreshejwe sisitemu yo gusukura neza cyane. Pt/C (5% yo gutwika uburemere) na Pd/C (5% yo gutwika uburemere) byaguzwe muri Sigma-Aldrich.
Gutunganya nanocrystals za CoZn-ZIF byakozwe hashingiwe ku buryo bwabanje hamwe n'impinduka zimwe na zimwe23,64. Ubwa mbere, 30 mmol Zn(NO3)2·6H2O (8.925 g) na 3.5 mmol Co(NO3)2·6H2O (1.014 g) byavanzwe bishongeshwa muri 300 ml ya methanol. Hanyuma, 120 mmol ya 2-methylimidazole (9.853 g) yashongeshejwe muri 100 ml ya methanol hanyuma yongerwa muri icyo gisubizo cyavuzwe haruguru. Uruvange rwavanzwe ku bushyuhe bw'icyumba mu gihe cy'amasaha 24. Amaherezo, icyo gikoresho cyatandukanijwe hakoreshejwe centrifugation kuri 6429 g mu gihe cy'iminota 10 hanyuma cyozwa neza na methanol inshuro eshatu. Ifu yavuyemo yamanitswe mu cyuma gishyushye kuri 60 ° C ijoro ryose mbere yo kuyikoresha.
Kugira ngo hakonjeshwe Co-SAs/NPs@NC-950, ifu yumye ya CoZn-ZIF yashyizwemo pyrolysis kuri 950 °C mu gihe cy'isaha imwe mu muvuduko wa gazi wa 6% H2 + 94% Ar, hamwe n'igipimo cyo gushyushya cya 5 °C/min. Icyitegererezo cyakonjeshejwe kugeza ku bushyuhe bw'icyumba kugira ngo haboneke Co-SA/NPs@NC-950. Kuri Co-SAs/NPs@NC-850 cyangwa Co-SAs/NPs@NC-750, ubushyuhe bwa pyrolysis bwarahindutse kugeza kuri 850 na 750 °C, uko bikurikirana. Ingero zateguwe zishobora gukoreshwa nta yandi mabwiriza, nko gukata aside.
Ibipimo bya TEM (transmission electron mikroskopi) byakorewe kuri mikroskopi ya Thermo Fisher Titan Themis 60-300 "cube" ifite agakoresho ko gukosora amashusho n'indorerwamo ya 300 kV. Igerageza rya HAADF-STEM ryakozwe hakoreshejwe mikroskopi ya FEI Titan G2 na FEI Titan Themis Z ifite ibikoresho byo gupima no gukosora amashusho, ndetse n'ibikoresho byo gupima ibice bine bya DF4. Amashusho ya elemental mapping ya EDS yabonetse kuri mikroskopi ya FEI Titan Themis Z. Isesengura rya XPS ryakozwe kuri spectrometer ya X-ray photoelectron (Thermo Fisher model ESCALAB 250Xi). XANES na spectra ya EXAFS ya Co K-edge byakusanyijwe hakoreshejwe ameza ya XAFS-500 (China Spectral Instruments Co., Ltd.). Ibikubiye muri Co byagenwe hakoreshejwe spectroscopy ya atome absorption (AAS) (PinAAcle900T). Ibipimo bya X-ray diffraction (XRD) byafashwe ku gipimo cya X-ray diffractometer (Bruker, Bruker D8 Advance, Ubudage). Isotherms zo kunyuza azote zabonetse hakoreshejwe igikoresho cyo kunyuza azote (Micromeritics, ASAP2020, USA).
Uburyo bwo kugabanya amazi mu kirere bwakorewe mu kirere cya argon, umwuka ukuweho hakurikijwe uburyo busanzwe bwa Schlenk. Umwanya w’ibiza warakuwemo hanyuma wuzuramo argon inshuro 6. Fungura amazi ya condenser hanyuma wongeremo catalyst (30 mg) na solvent (6 ml). Shyushya icyo gikoresho kugeza ku bushyuhe wifuza ukoresheje thermostat hanyuma ureke gihuze mu minota 30. Hanyuma aside formic (10 mmol, 377 μL) yongewe mu mwanya w’ibiza munsi ya argon. Hindura valve ya burette y’inzira eshatu kugira ngo ugabanye umuvuduko wa reactor, wongere ufunge, hanyuma utangire gupima ingano ya gaze yakozwe ukoresheje burette y’intoki (Ishusho S16). Nyuma y’igihe gisabwa kugira ngo reaction irangire, hakusanyijwe icyitegererezo cya gaze kugira ngo gisesengurwe hakoreshejwe syringe idakoresha gaze yakuwemo argon.
Igerageza ryo gushyushya ibintu mu buryo bw’ikirere ryakozwe kuri spectrometer ya Fourier transform infrared (FTIR) (Thermo Fisher Scientific, Nicolet iS50) ifite detector ya mercury cadmium telluride (MCT). Ifu ya catalyst yashyizwe mu kazu k’uburyo bw’imikorere (Harrick Scientific Products, Praying Mantis). Nyuma yo kuvura catalyst n’umugezi wa Ar (50 ml/min) ku bushyuhe bw’icyumba, icyitegererezo cyashyushye kugeza ku bushyuhe runaka, hanyuma gishyirwamo Ar (50 ml/min) mu gisubizo cya HCOOH hanyuma gisukwa mu kazu k’uburyo bw’imikorere bw’imikorere y’imiterere y’ikirere. Uburyo butandukanye bwo gushyushya ibintu. Spektorometero za infrared zanditswe mu byiciro kuva ku masegonda 3.0 kugeza ku isaha 1.
HCOOH, DCOOH, HCOOD na DCOOD bikoreshwa nk'ibice bya propylene karubone. Ibisigaye bihuye n'uburyo bwo gukuraho amazi muri HCOOH.
Imibare y’amahame ya mbere yakozwe hakoreshejwe uburyo bwa "density functional theory framework" muri package ya Vienna Ab initio modeling (VASP 5.4.4) 65,66. Akaremangingo ka superunit gafite ubuso bwa graphene (5 × 5) gafite uburebure bwa transverse bwa 12.5 Å kakoreshejwe nk'ishingiro rya CoN2C2 na CoN2C2-Co6. Intera y'ubusa irenga 15 Å yongewemo kugira ngo hirindwe imikoranire hagati y'ibice by'ishingiro byegeranye. Imikoranire hagati ya iyoni na electron isobanurwa n'uburyo bwa "amplified wave" (PAW) bwateganijwe65,67. Umumaro wa Perdue-Burke-Ernzerhoff (PBE) generalized gradient approximation (GGA) watanzwe na Grimm hamwe na van der Waals correction68,69 wakoreshejwe. Ibipimo byo guhuza ingufu n'ingufu zose ni 10−6 eV/atome na 0.01 eV/Å. Ingufu zaciwe kuri 600 eV hakoreshejwe gridi ya Monkhorst-Pack 2 × 2 × 1 K-point. Ingufu zikoreshwa muri ubu buryo zubatswe uhereye ku miterere y'ikoranabuhanga mu miterere ya C 2s22p2, N 2s22p3, Co 3d74s2, H 1 s1, na O 2s22p4. Ingufu zo kunyuzamo n'itandukaniro ry'ubucucike bwa electron bibarwa hakurwamo ingufu z'ubwoko bwa gaze na surface mu ngufu za sisitemu inyuzwamo umwuka hakurikijwe modele za adsorption cyangwa interface70,71,72,73,74. Gukosora ingufu za Gibbs zidafite umuriro bikoreshwa mu guhindura ingufu za DFT mu ngufu za Gibbs zidafite umuriro kandi bigashingira ku ruhare rwa vibration kuri entropy na zero point energy75. Uburyo bwa ascensing image-nudging elastic band (CI-NEB) bwakoreshejwe mu gushakisha imiterere y'impinduka ya reaction76.
Amakuru yose yabonetse n'ayasesenguwe muri ubu bushakashatsi ari mu nyandiko n'ibindi bikoresho by'inyongera cyangwa akaboneka ku mwanditsi ubisabye mu buryo bwumvikana. Amakuru y'inkomoko y'iyi nyandiko aratangwa.
Kode zose zakoreshejwe muri simulations ziherekeje iyi nkuru ziraboneka ku banditsi babisabye.
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