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Iterambere ry’ubuhinga bw’iyidrojeni riri mu mutima w’ubutunzi bw’ivyatsi bitotahaye. Nk’itegeko ry’ugushitsa ububiko bw’iyidrojeni, birakenewe ko habaho ibikoresho bikora kandi bishikamye vy’iyidrojeni (de)iyidrojeni. Gushika ubu, muri ako karere hakoreshwa cane ivyuma vy’agaciro bizimvye. Aha, dutanga iciyumviro c’igitabu gishasha c’igiciro gito gishingiye kuri cobalt (Co-SAs/NPs@NC) aho ibibanza vy’ivyuma bimwe bimwe bikwiragiye cane bifatanywa n’ibihimba vy’umubiri kugira ngo bishobore gukuraho aside formique neza. Hakoreshejwe ibikoresho vyiza kuruta ibindi vyose vy’ibice vya CoN2C2 binyanyagiye mu buryo bw’atome n’ibice vy’umuyagankuba vy’uburebure bwa 7-8 nm, hakoreshejwe carbonate ya propylene nk’ikinyobwa, habonetse umuyagankuba mwiza cane w’imiliyoni 1403,8 g-1 h-1, kandi nta n’umwe yatakaje inyuma y’ingendo 5. igikorwa, kikaba ari ciza incuro 15 kuruta Pd/C y’ubudandaji. Igerageza ry’igerageza ry’aho hantu ryerekana ko, ugereranyije n’ibintu bifitaniye isano n’atome imwe y’icuma be n’ibintu bitera umuriro, Co-SAs/NPs@NC yongera ubushobozi bwo gufata no gukora kw’urufunguzo rw’imbere rw’ivyuma bimwe bimwe HCOO*, gutyo bigatuma habaho ugucapura kw’imigenderanire ya CH. Ivyiyumviro vyerekana ko gushiramwo nanoparticules za cobalt bitera imbere mu guhindura d-band center y’atome imwe ya Co ikaba ahantu hakora, gutyo bigatuma habaho uguhuza hagati ya carbonyl O y’igice co hagati ca HCOO* n’igice ca Co, gutyo bikaba bigabanya inzitizi y’inguvu.
Ihidrojeni ifatwa nk’ikintu gihambaye gitwara inguvu mu mpinduka y’inguvu kw’isi yose kandi ishobora kuba umuvuduko w’ingenzi wo gushika ku ntambara y’umuyagankuba1. Kubera imiterere yayo nk’ugusha n’uburemere buke, ububiko n’ugutwara neza kw’iyidrojeni ni ibibazo nyamukuru mu gushitsa ubutunzi bw’iyidorojeni2,3,4. Ivyo bikoresho bitwara amazi (LOHCs), bikaba ari vyo bibika kandi bikarekura amazi biciye mu bikorwa vy’imiti, ni vyo vyasabwe nk’umuti. Ugereranije n’ivyuma vy’amazi, ivyo bintu (methanol, toluène, dibenzyltoluène, n’ibindi) biroroshe kandi biraryoshe gukoresha5,6,7. Mu bikoresho bitandukanye vy’imigenzo, aside formique (FA) irafise ubumara buke cane (LD50: 1,8 g/kg) n’ubushobozi bwa H2 bwa 53 g/L canke 4,4 wt%. Biragaragara ko FA ari yo LOHC yonyene ishobora kubika no kurekura ihydrogène mu bihe vyoroshe iyo hariho ibikoresho bikwiye, rero ntibisaba inguvu nyinshi zo hanze1,8,9. Nkako, ivyuma vyinshi vy’agaciro vyakozwe kugira ngo aside formique ivemwo amazi, nk’akarorero, ivyuma bikoreshwa na palladium birakora incuro 50-200 kuruta ivyuma bitazimvye10,11,12. Ariko rero, iyo uzirikanye igiciro c’ivyuma bikora, nk’akarorero, palladium irazimvye incuro zirenga 1000.
Cobalt, Ugushakashaka ivyuma bikora cane kandi bikomeye bikomeza gukwegera abashakashatsi benshi bo mu mashure yisumbuye no mu nganda13,14,15.
Naho ibikoresho bitazimvye bishingiye kuri Mo na Co, hamwe n’ibikoresho bikoreshwa na nanocatalysts bikozwe mu vyuma vy’agaciro/vy’agaciro,14,16 vyateguwe kugira ngo FA ikuremwo amazi, guhagarara kwavyo buhoro buhoro mu gihe c’ugusubiranamo ni ikintu kitazobura kubaho kubera ko ivyuma, CO2, na H2 bifata ahantu hakora. canke anions za formate (HCOO-), kwanduzwa kwa FA, uguteranira hamwe kw’ibice n’ubumara bwa CO bushoboka17,18. Twe n’abandi twaherutse kwerekana ko ibikoresho bikorana n’atome imwe (SACs) bifise ibibanza vya CoIINx binyanyagiye cane nk’ibibanza bikora bitera imbere mu bijanye n’ugusubiranamo n’uguhangana n’aside y’umubiri ugereranyije n’ibihimba vy’umubiri17,19,20,21,22,23,24. Muri ivyo bikoresho vya Co-NC, atome za N zikora nk’ibibanza bihambaye vyo guteza imbere FA deprotonation mu gihe zituma imiterere iguma ikomeye biciye mu guhuza n’atome ya Co yo hagati, mu gihe atome za Co zitanga ibibanza vyo gufata H no guteza imbere ugusenyuka kwa CH22, 25,26. Ikibabaje, igikorwa n'ugushikama kw'ivyo bikoresho bikiri kure y'ibikoresho vy'ubuhinga bwa none bihuye n'ibindi bitari bimwe (Ishusho 1) 13 .
Inguvu zirenze urugero zivuye mu bikoresho bishobora gusubirwamwo nk’izuba canke umuyaga zishobora guterwa n’uguhindura amazi n’umuyagankuba. Ihidrojeni ishobora kubikwa hakoreshejwe LOHC, ni ukuvuga amazi ashobora gusubira inyuma mu guhinduka kw’iyidrojeni no mu gukuraho ihidrojeni. Mu ntambwe yo gukuraho amazi, igicuruzwa conyene ni amazi, maze amazi atwara amazi agasubira uko yari ameze mbere, agasubira guhindurwa amazi. Amaherezo, iyo hydrogène yoshobora gukoreshwa mu bibanza bikoreramwo amavuta, mu mabateri, mu nyubakwa z’inganda no mu bindi.
Vuba aha, vyavuzwe ko igikorwa c’imbere c’ama SAC yihariye gishobora kwongerwa iyo hariho atome zitandukanye z’ivyuma canke ibindi bibanza vy’ivyuma bitangwa n’ibice vy’ivyuma (NPs) canke nanoclusters (NCs)27,28. Ivyo bica bituma habaho uburyo bwo gukomeza gufata no gukora kw’ivyo bihimba, be no guhindura ubuhinga bw’ubuhinga bwa geometrie n’imiterere y’ubuhinga bwa elegitoronike y’ibibanza vy’amaatome. Muri ubwo buryo, ugufata/ugukora kw’ibintu bishobora gutunganirizwa neza, bikaba bitanga ubushobozi bwiza bwo gutuma ibintu bigenda neza29,30. Ivyo bituma tugira iciyumviro co kurema ibikoresho bikwiye vy’ugutuma ibintu bigenda neza bifise ibibanza bikora vy’imigwi itandukanye. Naho SACs zanozwe zagaragaje ubushobozi bukomeye mu bikorwa vyinshi vy’ubuhinga bwo gutuma ibintu bigenda neza31,32,33,34,35,36, ku buryo tuzi, uruhara rwazo mu kubika ivyuma vy’amazi ntirutomoye. Muri ivyo, turatanga raporo y’ingene ubuhinga butandukanye kandi bukomeye bwo gukora ibikoresho vy’ivyuma bishingiye ku cobalt (Co-SAs/NPs@NCs) birimwo nanoparticules zisobanuwe n’ibibanza vy’ivyuma vy’umuntu ku giti ciwe. Ivyo bikoresho vyiza cane vyitwa Co-SAs/NPs@NC vyerekana ubushobozi bwiza cane bwo gukuraho amazi mu mazi, ivyo bikaba ari vyiza kuruta ibikoresho bitagira amazi bifise imiterere y’amazi (nka CoNx, atome imwe ya cobalt, cobalt@NC na γ-Mo2N) mbere n’ibikoresho vy’ivyuma vy’agaciro. In-situ characterization n’imibare ya DFT y’ibikoresho bikora vyerekana ko ibibanza vy’ivyuma bikora nk’ibibanza bikora, kandi nanoparticules z’ubu buhinga zituma d-band centre y’ama atome ya Co itera imbere, zigatuma HCOO* igira ubushobozi bwo gufata no gukora, gutyo bikagabanya inzitizi y’inguvu z’ivyo bihimba. .
Zeolite imidazolate frameworks (ZIFs) ni ibikoresho vy’ingero zitatu bisobanuwe neza bitanga ibikoresho vy’ivyuma bifise azote (ibikoresho vy’ivyuma-NC) kugira ngo bifashe ubwoko butandukanye bw’ivyuma37,38. Ku bw’ivyo, Co(NO3)2 na Zn(NO3)2 bifatanya na 2-methylimidazole iri muri metanoli kugira ngo bibe ivyuma bihuye n’ivyo mu mazi. Inyuma yo gucapura no kwumisha, CoZn-ZIF yarahinduwe umuriro ku bushuhe butandukanye (750–950 °C) mu kirere c’ibice 6% H2 na 94% Ar. Nk’uko vyerekanwa ku gishushanyo kiri musi, ibikoresho biva muri ivyo bifise ibiranga ahantu hakora bitandukanye kandi vyitwa Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 (Igishushanyo 2a). ) . Ivyiyumviro vy’igerageza vyihariye vy’intambwe zimwe zimwe z’ingenzi mu nzira y’ugukora ivyiyumviro biradondaguwe mu bishushanyo 1 na 2. C1-C3. Hakoreshejwe ubuhinga bwo gupima ubushuhe buhinduka (VTXRD) kugira ngo hakurikiranwe ingene iyo nzira itera imbere. Igihe ubushuhe bw'ivyuma bushitse kuri 650 °C, uburyo bwa XRD burahinduka cane kubera ugusenyuka kw'imiterere y'amabuye y'agaciro ya ZIF (Ishusho S4) 39 . Uko ubushuhe bugenda buragwira, isonga zibiri zagutse ziraboneka mu bishushanyo vya XRD vya Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 ku 20–30° na 40–50°, zigereranya isonga ry’umuyagankuba udafise ishusho (Ishusho C5). 40. Birabereye kumenya ko isonga ritatu gusa ry’ibiranga ryabonetse ku 44,2°, 51,5° na 75,8°, ry’ivyuma vy’ibara ry’agahama (JCPDS #15-0806), na 26,2°, ry’ibara ry’agahama ry’ibara ry’agahama (JCPDS # 41-1487). Ibara ry'imishwarara ya X rya Co-SAs/NPs@NC-950 ryerekana ko hariho ibintu bimeze nk'ivy'ibara ry'agahama ku gikoresho gitera umuriro41,42,43,44. Igishushanyo ca Raman kigaragaza ko Co-SAs/NPs@NC-950 isa n’iyifise isonga D na G rikomeye kandi ryinshi kuruta ibindi bipimo, ivyo bikaba vyerekana urugero rwo hejuru rw’uguhinduka kw’ibara ( Igishushanyo S6 ). Ikindi, Co-SAs/NPs@NC-950 yerekana uburebure bw’ubutaka n’ubunini bw’ibihengeri (1261 m2 g-1 na 0,37 cm3 g-1) kuruta ibindi bipimo kandi ZIF nyinshi ni ibikomoka kuri NC. ibikoresho (Ishusho S7 n’Imbonerahamwe S1). Ivyuma bipima uburemere bw’ibintu (AAS) vyerekana ko ivyuma bita cobalt biri mu bihimba vy’umubiri bita 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 nk’uko bigenda (Imbonerahamwe S2). Ivyo bita Zn biri muri Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 biragenda biragwira buhoro buhoro, ivyo bikaba biterwa n’uko ibice vya Zn bigenda biragabanuka kandi bikagenda bihinduka. Ukwongerekana kw’ubushuhe bw’ivyuma (Zn, ubushuhe bwo guteka = 907 °C) 45.46. Isesengurwa ry’ibintu (EA) ryerekanye ko ijana rya N rigabanuka uko ubushuhe bw’ivyuma vy’umuriro bugenda buragwira, kandi O nyinshi zishobora kuba ziterwa n’ugufata O2 y’amamolekule ivuye mu gushikirwa n’ikirere. (Imbonerahamwe S3). Ku rugero runaka rw’ivyo bita cobalt, nanoparticules n’ivyo bita coatoms bitandukanye birabana, ivyo bikaba bituma habaho ukwiyongera gukomeye kw’ibikorwa vy’ibikoresho bitera umuriro, nk’uko bizovugwa aha hepfo.
Igishushanyo c’ivy’ugukoranya Co-SA/NPs@NC-T, aho T ari ubushuhe bw’ugusenyuka (°C). b Ishusho ya TEM. c Ishusho y’Ishirahamwe ry’Igihugu/Igihugu @NC-950 AC-HAADF-STEM. Atome za Co zimwe zimwe zigaragazwa n’inziga zitukura. d Ibara ry'ibara ry'umubiri ry'i Co-SA/NPs@NC-950.
Ivyiza ni uko ubuhinga bwo gupima uburemere bw’ibintu (TEM) bwagaragaje ko hariho ibintu bitandukanye bifise ubunini bwa 7,5 ± 1,7 nm gusa muri Co-SAs/NPs@NC-950 ( Ibishushanyo 2 b na S8). Izo nanoparticules zipfutse n’ivyuma bimeze nk’ivyuma vyitwa graphite bifise azote. Igitigiri c’imirongo y’uruzitiro 0,361 na 0,201 nm gihuye n’ibice vy’ivyuma vy’ibara ry’agahama (002) n’ivy’ibara ry’agahama vy’ibara ry’agahama (111), uko bikurikirana. Ikindi, ubuhinga bwo gupima uburemere bw’ibintu (AC-HAADF-STEM) bwagaragaje ko Co NPs ziri muri Co-SAs/NPs@NC-950 zari zikikujwe n’amabuye y’agaciro menshi cane yitwa cobalt (Ishusho 2c). Ariko rero, atome za kobalt zitandukanye gusa ni zo zabonetse ku nfashanyo y’ibindi bipimo bibiri (Ishusho S9). Igishushanyo ca HAADF-STEM c’ibara ry’inguvu (EDS) kigaragaza ko C, N, Co n’ibice vya Co bitandukanye bigabanywa mu buryo bumwe muri Co-SAs/NPs@NC-950 (Ishusho 2d). Ivyo vyose vyerekana ko ibibanza vya Co binyanyagiye mu buryo bw’atome n’ibice vy’umuyagankuba bipfutse mu carbone imeze nk’iya graphite ifise N bishobora gufatanya neza n’ibibanza vya NC mu Co-SAs/NPs@NC-950, mu gihe ibibanza vy’ivyuma bitandukanye gusa.
Ivyerekeye uburemere bw’ibikoresho vyaronswe n’ivyo bihimba vy’umubiri vyari vyigwa hakoreshejwe ubuhinga bwa X-XPS (XPS). Ivyerekana XPS vy’ivyo bikoresho bitatu vyerekana ko hariho ibintu Co, N, C na O, ariko Zn yari muri Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 gusa (Ishusho 2). ). C10). Uko ubushuhe bw'izuba bugenda buragwira, ni ko n'umubare wose w'azote ugabanuka uko ubwoko bw'azote bugenda burahungabana maze bukabora bukaba imyuka ya NH3 na NOx ku bushuhe bwinshi (Imbonerahamwe S4) 47 . Gutyo, umubare wose w’ivyuma vy’umuyagankuba waragenda uragwira buhoro buhoro kuva ku bihimba vy’umubiri bita Co-SAs/NPs@NC-750 gushika ku bihimba vy’umubiri bita Co-SAs/NPs@NC-850 no ku bihimba vy’umubiri bita Co-SAs/NPs@NC-950 (Ibishushanyo S11 na S12). Ico kigereranyo gipfutse mu bushuhe bwinshi gifise igice gito c’ama atome y’azote, ivyo bikaba bisobanura ko umubare w’ibintu bitwara NC muri Co-SAs/NPs@NC-950 ukwiye kuba muto kuruta uwo mu bindi bigereranyo. Ivyo bituma habaho ugusenyuka gukomeye kw’ibihimba vya cobalt. Ibara ry'umuco ryerekana isonga ribiri C=O (531,6 eV) na C–O (533,5 eV), hakurikijwe (Ishusho S13) 48 . Nk’uko vyerekanwa ku gishushanyo ca 2a, urutonde rwa N 1s rushobora gutorwa mu bice bine vy’ibimenyetso vy’azote ya piridine N (398,4 eV), pirrole N (401,1 eV), graphite N (402,3 eV) na Co-N (399,2 eV). Amabondi ya Co-N ari muri ivyo bigereranyo vyose bitatu, bikaba vyerekana ko atome zimwe zimwe za N zihujwe n’ibibanza vy’ivyuma bimwe, ariko ibiranga biratandukanye cane49. Gukoresha ubushuhe bwinshi bw’ivyuma bishobora kugabanya cane ubwoko bwa Co-N kuva kuri 43,7% muri Co-SA/NPs@NC-750 gushika kuri 27,0% muri Co-SAs/NPs@NC-850 na Co 17,6%@NC-950. mu -CA/NPs, ivyo bikaba bihuye n’ukwiyongera kw’ibirimwo C (Ishusho 3a), bikaba vyerekana ko umubare wabo w’uguhuza Co-N ushobora guhinduka maze ugasubirizwa igice n’atome za C50. Igishushanyo ca Zn 2p kirerekana ko ico kintu kiriho cane cane mu buryo bwa Zn2+. (Ishusho S14) 51. Ibara ry’umuco rya Co 2p ryerekana isonga zibiri zigaragara ku 780,8 na 796,1 eV, zikaba ziterwa na Co 2p3/2 na Co 2p1/2, hakurikijwe (Ishusho 3b). Ugereranije na Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750, isonga rya Co-N muri Co-SAs/NPs@NC-950 rihindurwa rikaja ku ruhande rwiza, bikaba vyerekana ko atome imwe ya Co iri ku ruhande -SAs/NPs@NC-950 ifise urugero rwo hejuru rw’ugusenyuka kw’amashanyarazi muri Co-SAs/NPs@NC-950. Birabereye kumenya ko Co-SAs/NPs@NC-950 yonyene yerekanye isonga ry’intege nke ry’ivyuma vy’agaciro ka zero (Co0) ku 778,5 eV, ivyo bikaba vyerekana ko hariho nanoparticules zivuye mu gukoranya ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma vy’ivyuma.
a N 1s na b Co 2p z’imirongo y’ibara ry’umuhondo ry’i Co-SA/NPs@NC-T. c XANES na d FT-EXAFS imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo 950, imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo 850 n'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo y'imirongo 750. e Ivyiyumviro vy'imirongo y'imirongo ya WT-EXAFS vy'Ibihugu vy'Igihugu/Ibihugu@NC-950, Ibihugu/Ibihugu@NC-850, n'Ibihugu/Ibihugu@NC-750. f FT-EXAFS ibereye umurongo w'ibara ry'umubiri ku Co-SA/NPs@NC-950.
Haciye hakoreshwa ubuhinga bwo gupima imishwarara y’izuba (XAS) kugira ngo hasuzumwe imiterere y’ubuhinga bwa elegitoronike n’ibidukikije vy’uguhuza ubwoko bwa Co mu citegererezo categuwe. Ivyerekeye uburemere bwa cobalt mu Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 Ubuhinga bwo ku ruhande bugaragazwa n’ugufata imishwarara ya X iri hafi y’aho hantu ku ruhande rwa Co-K (XANES). Nk’uko vyerekanwa ku gishushanyo ca 3c, ukunywa hafi y’urubibi rw’ivyo bipimo bitatu kuri hagati y’ibipande vya Co na CoO, bikaba vyerekana ko uburemere bw’ubwoko bwa Co buva kuri 0 gushika kuri +253. Ikindi, habonetse uguhinduka kw’inguvu ziri hasi kuva kuri Co-SAs/NPs@NC-950 gushika kuri Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750, ivyo bikaba vyerekana ko Co-SAs/NPs@NC-750 ifise ikibanza c’uguhinduka kw’imitsi kiri hasi. Guhindura urutonde. Dushingiye ku bisubizo vy’uguhuza umurongo, igitigiri c’uburemere bwa Co-SAs/NPs@NC-950 kigereranywa ko ari +0.642, kikaba kiri hasi y’igitigiri c’uburemere bwa Co-SAs/NPs@NC-850 (+1.376). 750 (+1.402). Ivyo bimenyetso vyerekana ko ivyiyumviro vy’uguhinduka kw’ibice vya cobalt biri muri Co-SAs/NPs@NC-950 bigabanywa cane, ivyo bikaba bihuye n’ibisubizo vya XRD na HADF-STEM kandi bishobora gusigurwa n’ukubaho kumwe kw’ibice vya cobalt nanoparticules na cobalt imwe. . Co atoms 41. Ihinduka rya Fourier ry’imiterere myiza y’ugufata imishwarara (FT-EXAFS) y’uruzitiro rw’urubibi rwa Co K rwerekana ko isonga nyamukuru riri ku 1,32 Å ari iry’igipfukisho ca Co-N/Co-C, mu gihe inzira y’ugushwiragira kw’ivyuma Co -Co iri ku 2,18 gusa iboneka mu Co-SAs /Ishusho50d Å). Ikindi kandi, igicapo c’umurongo w’ihinduka ry’umuvuduko (WT) kigaragaza uburemere burengeye 6.7 Å-1 bushingiye kuri Co-N/Co-C, mu gihe Co-SAs/NPs@NC-950 yonyene yerekana uburemere burengeye ubundi bwose bushingiye kuri 8.8. Iyindi nzira y’uburemere burengeye iri ku Å−1 ku nzira ya Co–Co (Ishusho 3e). Ikindi, isesengura rya EXAFS ryakozwe n’umukozi ryerekanye ko ku bushuhe bwa pyrolyse bwa 750, 850 na 950 °C, imibare y’uguhuza Co-N yari 3,8, 3,2 na 2,3, hakurikijwe, imibare y’uguhuza Co-C na yo yari 0, 0.1, S.5 (Ishusho1,1 na S.5). Mu buryo butomoye, ivyo biherutse gusohoka bishobora guterwa n’ukubaho kw’ibice vya CoN2C2 n’ibice vy’ubuhinga bwa nano mu Co-SAs/NPs@NC-950. Mu buryo bunyuranye, mu bihugu vya Co-SA/NPs@NC-850 no mu bihugu vya Co-SA/NPs@NC-750, ni ibice vya CoN3C na CoN4 gusa biriho. Biragaragara ko iyo ubushuhe bw’ivyuma vy’umuriro bugenda buragwira, atome za N ziri mu gice ca CoN4 zisubirizwa buhoro buhoro n’atome za C, n’ivyuma vya cobalt CA bigakorana kugira ngo bibe nanoparticules.
Ivyiyumviro vy’ugusubiza vyari vyigwa mbere vyakoreshejwe mu kwiga ingaruka z’ivy’ugutegura ku mico y’ibikoresho bitandukanye (Ishusho S16)17,49. Nk’uko vyerekanwa ku gishushanyo ca 4 a, igikorwa c’aba Co-SAs/NPs@NC-950 ni kinini cane kuruta ic’aba Co-SAs/NPs@NC-850 n’aba Co-SAs/NPs@NC-750. Ivyiza ni uko ivyo bipimo vyose bitatu vya Co vyateguwe vyerekanye ubushobozi bwiza cane ugereranije n’ibikoresho vy’ubudandaji vy’agaciro (Pd/C na Pt/C). Ikindi, ivyerekanwa vya Zn-ZIF-8 na Zn-NC ntivyari bikora cane ku bijanye no gukuraho amazi mu mazi, ivyo bikaba vyerekana ko utugingo ngengabuzima twa Zn tutari ahantu hakora, ariko ingaruka zavyo ku gikorwa ni nke cane. Ikindi, igikorwa ca Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 caragizwe n'ihinduka ry'umuriro ku bushuhe bwa 950°C mu kiringo c'isaha imwe, ariko cari hasi y'ica Co-SAs/NPs@NC-750 . @NC-950 (Ishusho S17). Ivyerekeye imiterere y’ivyo bikoresho vyerekanye ko hariho nanoparticles za Co mu bipimo vyasubiwemwo, ariko uburebure bw’uburebure buke bwihariye n’ukubura carbone imeze nk’iya graphite vyatumye habaho igikorwa gitoyi ugereranyije na Co-SAs/NPs@NC-950 (Ishusho S18–S20). Ibikorwa vy’ibigereranyo bifise ingano zitandukanye z’imbere y’ibindi bihimba vya Co na vyo nyene vyagereranywa, igikorwa kinini cane kigaragazwa ku kwongerako 3,5 mol (Imbonerahamwe S6 n’Igishushanyo S21). Biragaragara ko uguhingura ibibanza bitandukanye vy’ivyuma biterwa n’ivy’iyidrojeni iri mu kirere c’ivyuma bitera umuriro be n’igihe ivyuka bimara. Ku bw’ivyo, ibindi bikoresho vya Co-SAs/NPs@NC-950 vyasuzumwe ku bikorwa vyo gukuraho amazi mu mazi. Ibikoresho vyose vyerekanye ko bikora neza cane; ariko nta n’imwe muri zo yari nziza kuruta Co-SAs/NPs@NC-950 (Ibishushanyo S22 na S23). Ivyo bikoresho vyerekanye ko uko igihe co gusenyuka kigenda kirushiriza, ibirimwo mu bibanza vya Co-N bigenda biragabanuka buhoro buhoro kubera uguteranira hamwe kw’amaatome y’ivyuma mu bihimba vy’umubiri, ivyo bikaba bisigura itandukaniro ry’ibikorwa hagati y’ibigereranyo bifise igihe co gusenyuka co hagati ya 100-2000. itandukaniro. 0,5 h, 1 h, na 2 h (Ibishushanyo S24–S28 n’Imbonerahamwe S7).
Igishushanyo c’ubunini bwa gazi n’igihe kiboneka mu gihe co gukuraho amazi mu bihimba vy’amavuta hakoreshejwe ibintu bitandukanye bitera umuriro. Ivyo bishobora gutuma umuntu agira ico akora: PC (10 mmol, 377 μl), ikintu gitera umuriro (30 mg), PC (6 ml), Tback: 110 °C, ubuhinga: 98 °C, ibice 4 b Co-SAs/NPs@NC-950 ( 30 mg), ibintu bitandukanye bitera umuriro. c Kugereranya ibipimo vy’uguhinduka kw’imiyaga y’ibinyabuzima bitandukanye mu binyabuzima ku 85–110 °C. d Igerageza ryo gusubira gukoresha ibintu bishaje Co-SA/NPs@NC-950. Ivyerekeye inyishu: FA (10 mmol, 377 μl), Co-SAs/NPs@NC-950 (30 mg), igisubizo (6 ml), Tset: 110 °C, Inyishu: 98 °C, buri nzira y'inyishu imara isaha imwe . Imirongo y'amakosa igereranya ukunyuranya kw'imirongo ngenderwako biharuwe bivuye ku bipimo bitatu bikora.
Muri rusangi, ubushobozi bw'ibikoresho bitera FA gukuraho amazi buvana cane n'ingene bigenda, cane cane igikoresho gikoreshwa8,49. Igihe hakoreshwa amazi nk’ikinyobwa, Co-SAs/NPs@NC-950 yerekanye igipimo kinini c’inyishu y’intango, ariko uguhagarara kwabaye, bishoboka ko ari kubera amaprotoni canke H2O18 yigaruriye ahantu hakora. Igerageza ry’ivyo bikoresho mu binyabuzima nk’ivyo bita 1,4-dioxane (DXA), n-butyl acetate (BAC), toluene (PhMe), triglyme na cyclohexanone (CYC) na vyo nyene ntivyerekanye ko hariho iterambere, kandi mu binyabuzima bita propylène (PC) ) (Ishusho 4b n’Imbonerahamwe S8). Na vyo nyene, ivyongera nk’ivyo bita triethylamine (NEt3) canke sodium formate (HCCONa) nta yindi ngaruka nziza vyari bifise ku bikorwa vy’ivyo bikoresho (Ishusho S29). Mu bihe vyiza vy’ugusubiza, umusaruro wa gazi washitse kuri 1403.8 mL g−1 h−1 (Ishusho S30), ivyo bikaba vyari vyinshi cane kuruta ibindi vyose vyari vyaravuzwe mbere ko bitera Co (harimwo SAC17, 23, 24). Mu ngeragezwa zitandukanye, hatarimwo inyishu mu mazi no mu vyongeweko formate, habonetse ubushobozi bwo gukuraho amazi n’ugukuraho amazi bushika kuri 99,96% (Imbonerahamwe S9). Inguvu z’ugukora ziharuwe ni 88,4 kJ/mol, zigereranywa n’inguvu z’ugukora z’ibikoresho vy’ivyuma vy’agaciro (Ishusho S31 n’Imbonerahamwe S10).
Ikindi, twagereranije ibindi bikoresho bitandukanye bifasha mu gukuraho amazi mu mazi mu bihe bisa n’ivyo (Ishusho 4c, imbonerahamwe S11 na S12). Nk’uko vyerekanwa ku gishushanyo ca 3c, igipimo c’uguhingura gazi ca Co-SAs/NPs@NC-950 kirenze ic’ibikoresho vyinshi bizwi vy’ivyuma bitandukanye kandi ni incuro 15 na 15 kuruta ivy’ubudandaji 5% Pd/C na 5% Pd/C, hakurikijwe, n’incuro 10 rimwe. % Pt/C ivyuka.
Ikintu gihambaye c’ikoreshwa ryose ry’ibinyabuzima (de)hydrogenation catalysts ni ukudahungabana kwavyo. Ni co gituma hakozwe urutonde rw’igerageza ryo gusubira gukoresha ibintu hakoreshejwe Co-SAs/NPs@NC-950. Nk’uko vyerekanwa ku gishushanyo ca 4 d, igikorwa ca mbere n’uguhitamwo ibikoresho vyagumye bitahindutse mu bihe bitanu bikurikiranye (raba kandi imbonerahamwe S13). Ivyigwa vy’igihe kirekire vyarakozwe kandi gazi yarongerekanye mu buryo bw’umurongo mu masaha 72 (Ishusho S32). Igitigiri ca cobalt cari muri Co-SA/NPs@NC-950 cakoreshejwe cari 2,5 wt%, kikaba cari hafi cane y’ivyo mu gikoresho gishasha co gutuma ibintu bigenda neza, ivyo bikaba vyerekana ko ata n’imwe igaragara y’ugusesagura cobalt (Imbonerahamwe S14). Nta mpinduka y’ibara igaragara canke uguteranira hamwe kw’ibihimba vy’ivyuma vyabonetse imbere n’inyuma y’ivyo bihimba ( Igishushanyo S33 ). AC-HAADF-STEM na EDS y’ibikoresho vyakoreshejwe mu ngeragezwa z’igihe kirekire vyerekanye ukugumya n’ugushwiragira kumwe kw’ibibanza vy’ugushwiragira kw’atome kandi nta mpinduka zikomeye z’imiterere (Ibishushanyo S34 na S35). Ivyiyumviro vy’ibiranga Co0 na Co-N biracariho muri XPS, bikaba vyerekana ko Co NPs zibaho hamwe n’ibibanza vy’ivyuma ku giti cabo, ivyo na vyo bikaba vyemeza ko igikoresho co gutuma Co-SAs/NPs@NC-950 gikora neza (Ishusho S36).
Kugira ngo hamenyekane ibibanza bikora cane bijejwe gukuraho amazi muri aside formique, ibikoresho vyatoranijwe bifise ikibanza kimwe gusa c’ivyuma (CoN2C2) canke Co NP vyateguwe bishingiye ku nyigisho za kera17. Urutonde rw'ibikorwa vy'ugukuraho amazi y'aside formique vyabonetse mu bihe nk'ivyo ni Co-SAs/NPs@NC-950 > Co SA > Co NP (Imbonerahamwe S15), vyerekana ko ibibanza vya CoN2C2 bishize ahabona bikora cane kuruta NPs . Ivyiyumviro vyerekana ko uguhinduka kw’iyidrojeni gukurikira ivyifuzo vy’urutonde rwa mbere, ariko imirongo y’imirongo myinshi ku bihimba bitandukanye vy’ivyuma vy’ibara ry’agahama ntibihuye, ivyo bikaba vyerekana ko ivyifuzo bitavana gusa n’aside formique, ariko kandi bivana n’aho ikora (Ishusho 2). C37). Ibindi vyigwa vyerekeye ubuhinga bw’imigenderanire vyerekanye ko, kubera ko ata nsonga z’ivyuma vya cobalt ziriho mu gusesangura imishwarara ya X, urutonde rw’imigenderanire y’imigenderanire mu bijanye n’ivyo cobalt irimwo rwabonetse ko ari 1,02 ku rwego rwo hasi (munsi ya 2,5%), ivyo bikaba vyerekana ko ibibanza vya cobalt vy’atome imwe bigabanywa hafi mu buryo bumwe. nyamukuru. ahantu hakora (imirongo S38 na S39). Iyo ibirimwo ibice vya Co bishitse kuri 2,7%, r iraduga bukwi na bukwi, ivyo bikaba vyerekana ko izo nanoparticules zikorana neza n’atome zimwezimwe kugira ngo zironke igikorwa kinini cane. Uko ibirimwo ibice vya Co birushirizaho kwiyongera, ni ko iyo nzira iba idaca mu murongo, ivyo bikaba bijana n’ukwiyongera kw’umubare w’ibice vy’umubiri vy’agaciro kanini be n’ukugabanya ibibanza vy’ibihimba vy’umubiri bimwe bimwe. Gutyo, ubushobozi bwo gukuraho amazi mu LC bwa Co-SA/NPs@NC-950 buva ku nyifato y’ubufatanye y’ibibanza vy’ivyuma n’ibihimba vy’umubiri.
Ivyigwa vyimbitse vyakozwe hakoreshejwe ubuhinga bwa Fourier bwo guhindura ivyiyumviro (in situ DRIFT) kugira ngo hamenyekane ibintu bifasha mu gusubiza ibintu mu gihe c’ivyo bikorwa. Inyuma yo gushusha ivyerekanwa ku bushuhe butandukanye bw’ugusubira inyuma inyuma yo kwongerako aside formique, habonetse imigwi ibiri y’incuro (Ishusho 5a). Ivyiyumviro bitatu vy’ibiranga HCOOH* biboneka ku 1089, 1217 na 1790 cm-1, ivyo bikaba biterwa n’uguhungabana kw’ugutambagira CH π (CH) hanze y’indege, uguhungabana kw’ugutambagira kwa CO ν (CO) n’uguhungabana kw’ugutambagira kwa C=O ν (C=O) respectly,45. Iyindi nkuru y’isonga iri ku 1363 na 1592 cm-1 ihuye n’uguhungabana kwa OCO guhuye νs(OCO) n’uguhungabana kw’ugutambagira kwa OCO kudahuye νas(OCO)33.56 HCOO*, uko bikurikirana. Uko iyo nzira igenda irabandanya, ni ko n’isonga ry’ubwoko bwa HCOOH* na HCOO* rigenda rizimangana buhorobuhoro. Muri rusangi, ukubora kwa aside formique birimwo intambwe zitatu nyamukuru: (I) gufata aside formique ku bibanza bikora, (II) gukuraho H biciye mu nzira ya formate canke carboxylate, na (III) gufatanya H zibiri zifatanye kugira ngo zivemwo ihydrogène. HCOO* na COOH* ni vyo bifasha mu kumenya inzira za formate canke carboxylate, uko zikurikirana57. Dukoresheje uburyo bwacu bwo gutuma ibintu bigenda neza, habonetse gusa isonga ry’akaranga HCOO*, ivyo bikaba vyerekana ko ukubora kwa aside formique kuba gusa biciye mu nzira ya aside formique58. Ivyo nyene vyabonetse ku bushuhe bwo hasi cane bwa 78 °C na 88 °C (igishushanyo S40).
Ivyerekana ivyerekeye ugukura kw’amazi kwa HCOOH ku Co-SAs/NPs@NC-950 na b Co SAs. Inkuru y’imigani yerekana ibihe vy’ugusubiza ku kibanza. c Guhinduka kw’umubare w’umuyagankuba ukoreshwa hakoreshejwe ibikoresho bitandukanye vyo gushirako amazina y’isotope mu gihe. d Amakuru y’ingaruka z’isotope y’umubiri.
Igerageza nk’iryo nyene ry’i DRIFT ryakozwe ku bikoresho bifitaniye isano Co NP na Co SA kugira ngo higwe ingaruka z’ubufatanye muri Co-SA/NPs@NC-950 ( Ibishushanyo 5 b na S41). Ivyo bikoresho vyose vyerekana imigenderanire isa n’iyo, ariko isonga ry’ibiranga HCOOH* na HCOO* rirahinduka gatoyi, ivyo bikaba vyerekana ko gushiramwo Co NPs bihindura imiterere y’ubuhinga bwa elegitoronike y’ikibanza c’atome imwe. Isonga ry’ikiranga νas(OCO) riboneka muri Co-SAs/NPs@NC-950 na Co SA ariko ntiriboneka muri Co NPs, bikaba vyerekana kandi ko ikintu kiri hagati kiboneka iyo wongeyeko aside ya formique ari aside ya formique y’amano amwe ihagaze ku ruhande rw’umunyu w’indege. kandi ifatanywa na SA nk'aho ikora 59 . Birabereye kumenya ko hariho ukwiyongera gukomeye kw’uguhungabana kw’isonga ry’ibiranga π(CH) na ν(C = O), ivyo bikaba biboneka ko vyatumye HCOOH* ihinduka kandi bikaba vyorosha inyishu. Ivyo vyatumye, isonga ry’ibiranga HCOOH* na HCOO* muri Co-SAs/NPs@NC hafi rizimangana inyuma y’iminota 2 y’ugusubiranamo, ivyo bikaba vyihuta kuruta ivy’ibikoresho vy’ivyuma bimwe (iminota 6) n’ivy’ibinyabuzima bishingiye ku bihimba bitobito (iminota 12). . Ivyo vyose vyemeza ko gutera imiti y’ibinyabuzima bifise ubushobozi bwo gufata n’ugukora kw’ibintu biri hagati, gutyo bikaba vyihuta gusubiza ibintu nk’uko vyavuzwe haruguru.
Kugira ngo hasuzumwe neza inzira y’ugusubiza no kumenya intambwe igena urugero (RDS), ingaruka za KIE zakozwe hari Co-SAs/NPs@NC-950. Aha, isotope zitandukanye z’aside formique nka HCOOH, HCOOD, DCOOH na DCOOD ni zo zikoreshwa mu nyigisho za KIE. Nk’uko vyerekanwa ku gishushanyo ca 5c, igipimo c’ugukuraho amazi kigabanuka mu buryo bukurikira: HCOOH > HCOOD > DCOOH > DCOOD. Ikindi, agaciro k’ibinyabuzima bita KHCOOH/KHCOOD, KHCOOH/KDCOOH, KHCOOH/KDCOOD na KDCOOH/KDCOOD kaharuwe ko ari 1,14, 1,71, 2,16 na 1,44, hakurikijwe (Ishusho 5d). Gutyo, ugucapura kw’imigenderanire ya CH muri HCOO* kwerekana agaciro ka kH/kD >1.5, vyerekana ingaruka nini y’imigenderanire60,61, kandi bisa n’ibigereranya RDS y’ugukuraho amazi kwa HCOOH kuri Co-SAs/NPs@NC-950.
Ikindi, imibare ya DFT yarakozwe kugira ngo umuntu atahure ingaruka z’ibihimba vy’umubiri bifise imiti ku gikorwa c’imbere ca Co-SA. Ivyitegererezo vya Co-SAs/NPs@NC na Co-SA vyubatswe bishingiye ku ngeragezwa zagaragajwe n’ibikorwa vya kera (Ishusho 6a na S42)52,62. Inyuma y’ugutuma ubuhinga bugenda neza, utugingo ngengabuzima dutoduto twa Co6 (CoN2C2) tubana n’ibice vy’atome imwe twamenyekanye, kandi uburebure bw’imigenderanire ya Co-C na Co-N muri Co-SA/NPs@NC bwamenyekanye ko ari 1,87 Å na 1,90 Å, hakurikijwe. , ivyo bikaba bihuye n’ivyavuye mu bikorwa vya XAFS. Igiharuro c’uburemere bw’ibice vy’ibihugu (PDOS) kigaragaza ko atome imwe y’icuma ca Co n’igice c’ivyuma (Co-SAs/NPs@NC) vyerekana uguhuza cane hafi y’urugero rwa Fermi ugereranyije na CoN2C2, bikaba bituma haba HCOOH. Ivyo guhindura ama elegitoroni aboze birakora neza cane ( Ibishushanyo 6b na S43). Ivyumba vy’umurongo wa d-band bihuye n’ivyo Co-SAs/NPs@NC na Co-SA vyaharuwe ko ari -0.67 eV na -0.80 eV, hakurikijwe, muri vyo ukwiyongera kwa Co-SAs/NPs@NC kwari 0.13 eV, ivyo bikaba vyatumye inyuma y’ugushiraho NP, ugufatanya kw’imiterere y’amashanyarazi ya HCOO*N kwabaye. Itandukaniro ry’uburemere bw’amashanyarazi ryerekana igicu kinini c’ama elegitoroni gikikuje igice ca CoN2C2 n’igice ca nano, bikaba vyerekana ko hariho ugukorana gukomeye hagati yavyo kubera uguhinduranya ama elegitoronike. Hafatanijwe n’isesengura ry’imishahara ya Bader, vyabonetse ko Co inyanyagiye mu buryo bw’atome yatakaje 1.064e muri Co-SA/NPs@NC na 0.796e muri Co SA ( Igishushanyo S44 ). Ivyo bimenyetso vyerekana ko ugushiramwo nanoparticules bituma electrons zigabanuka mu bibanza vya Co, bikaba bituma habaho ukwiyongera kwa Co valence, ivyo bikaba bihuye n’ibimenyetso vya XPS (Ishusho 6c). Ivyerekeye imigenderanire ya Co-O y’ugufatanya kwa HCOO kuri Co-SAs/NPs@NC na Co SA vyasuzumwe hakoreshejwe kubara umugwi wa Hamiltonian w’inzira y’amabuye y’agaciro (COHP)63. Nk’uko vyerekanwa ku gishushanyo ca 6 d, agaciro kabi n’agaciro ka -COHP gahuye n’imiterere y’ugufatanya n’imiterere y’ugufatanya, uko bikurikirana. Inkomezi z’ubufatanye bwa Co-O zifashwe na HCOO (Co-carbonyl O HCOO*) zasuzumwe hakoreshejwe ugushiramwo agaciro ka -COHP, kari 3,51 na 3,38 ku Co-SAs/NPs@NC na Co-SA, uko bikurikirana. HCOOH adsorption na yo yerekanye ibisubizo nk’ivyo: ukwiyongera kw’agaciro k’intege nke ka -COHP inyuma y’ugutera nanoparticles vyerekana ukwiyongera kw’ubufatanye bwa Co-O, gutyo bigatuma HCOO na HCOOH bikora ( Igishushanyo S45 ).
950 imiterere y’uruzitiro. b PDOS Ishirahamwe ry’Igihugu/NP@NC-950 n’Ishirahamwe ry’Igihugu. c 3D isosurface y’itandukaniro ry’uburemere bw’ivyuma vy’ugufata HCOOH ku Co-SA/NPs@NC-950 na Co-SA. (d) pCOHP y’imigenderanire ya Co-O ifashwe na HCOO kuri Co-SA/NPs@NC-950 (ibubamfu) na Co-SA (iburyo). e Inzira y’inyishu y’ugukuraho amazi kwa HCOOH ku Co-SA/NPs@NC-950 na Co-SA.
Kugira ngo umuntu atahure neza ubushobozi bwiza bwo gukuraho amazi bwa Co-SA/NPs@NC, inzira y’ugusubiza n’inguvu vyamenyekanye. Mu buryo bwihariye, ugukuraho amazi muri FA birimwo intambwe zitanu, harimwo uguhindura HCOOH ngo ibe HCOOH*, HCOOH* ngo ibe HCOO* + H*, HCOO* + H* ngo ibe 2H* + CO2*, 2H* + CO2* ngo ibe 2H* + CO2, na 2H* muri H2 (Ishusho 6e). Inguvu z’ugufata z’ibihimba vy’umubiri vy’aside formique ku ruhande rw’igikoresho gitera umuriro biciye mu mwuka w’ikirere (oxygène carboxylique) ni ntoyi kuruta biciye mu mwuka w’ikirere w’umubiri (Ibishushanyo S46 na S47). Hanyuma, kubera inguvu ziri munsi, iyo adsorbate ikunda guca mu nzira y’ugucapura kw’imigenderanire ya OH kugira ngo ikore HCOO* aho guca mu nzira y’ugucapura kw’imigenderanire ya CH kugira ngo ikore COOH*. Muri ico gihe nyene, HCOO* ikoresha uburyo bwo gufata ibintu bifise amenyo amwe, ivyo bikaba bituma imigenderanire igabanywa, bigatuma habaho CO2 na H2. Ivyo bimenyetso bihuye n’ukubaho kw’isonga rya νas(OCO) muri in situ DRIFT, bikaba vyerekana kandi ko ugusenyuka kwa FA kuba biciye mu nzira ya formate mu nyigisho yacu. Ni ngombwa kumenya ko hakurikijwe ingero za KIE, ugusenyuka kwa CH gufise inzitizi y’inguvu z’ugusubiza hejuru cane kuruta izindi ntambwe z’ugusubiza kandi guserukira RDS. Intambamyi y’inguvu y’umurongo mwiza w’ivyuma bitera umuriro Co-SAs/NPs@NC ni 0.86 eV iri hasi y’iya Co-SA (1.2 eV), ivyo bikaba bituma ubushobozi bwo gukuraho amazi muri rusangi butera imbere cane. Ivyiza ni uko ukubaho kw’ibihimba vy’umubiri bitunganya imiterere y’ubuhinga bwa elegitoronike y’ibibanza vy’ubuhinga bwa none, ivyo bikaba bituma habaho ugufata no gukora kw’ibihimba vyo hagati, gutyo bikagabanya inzitizi y’ugusubiranamo no gutuma habaho uguhingura ivyuma vy’amazi.
Mu ncamake, twerekana ku ncuro ya mbere ko ubushobozi bwo gutuma ivyuma bikora ivyuma bishobora guterwa imbere cane hakoreshejwe ibikoresho bifise ibibanza vy’ivyuma bimwe bimwe bigabanywa cane be n’utugingo ngengabuzima dutoduto. Ico ciyumviro cararemejwe n’ugukoranya ibikoresho vy’ivyuma bimwe bishingiye kuri cobalt bihinduwe n’ibihimba vy’umubiri (Co-SAs/NPs@NC), hamwe n’ibikoresho bifitaniye isano n’ivyo bifise gusa ibibanza vy’ivyuma bimwe (CoN2C2) canke Co NPs. Ivyo bikoresho vyose vyateguwe hakoreshejwe uburyo bworoshe bwo gutera umuriro mu ntambwe imwe. Isesengurwa ry’imiterere yerekana ko igikoresho ciza kuruta ibindi vyose (Co-SAs/NPs@NC-950) gifise ibice vya CoN2C2 binyanyagiye mu buryo bw’atome n’utugingo ngengabuzima dutoduto (7-8 nm) dufise azote n’umuyagankuba umeze nk’uwa graphite. Ifise ubushobozi bwiza cane bwo gutanga gazi igera kuri 1403,8 ml g-1 h-1 (H2:CO2 = 1,01:1), ubushobozi bwo guhitamwo H2 na CO bugera kuri 99,96% kandi ishobora kuguma ikora imisi myinshi. Ibikorwa vy’ico gikoresho bitera umuriro birenze ibikorwa vy’ibikoresho bimwebimwe bitera umuriro vyitwa Co SA na Pd/C incuro 4 n’incuro 15. Igerageza rya DRIFT ryerekana ko ugereranyije na Co-SA, Co-SAs/NPs@NC-950 yerekana ubushobozi bukomeye bwo gufata HCOO*, ari vyo bihambaye ku nzira ya formate, kandi nanoparticules zishobora gutuma HCOO* ikora no kwihutisha C–H. Ivyo bihimba vy’umubiri vyamenyekanye ko ari RDS. Ivyiyumviro vyerekana ko Co NP doping yongera d-band centre y’atome imwe imwe ya Co n’ibice 0.13 eV biciye mu gukorana, bikongera ubushobozi bwo gufata HCOOH* na HCOO* hagati, gutyo bikagabanya inzitizi y’ugusubira inyuma kuva kuri 1.20 eV ku Co SA gushika kuri 0 .86 eV. Ni we afise inshingano yo gukora neza cane.
Mu buryo bwagutse, ubu bushakashatsi buratanga ivyiyumviro vyo guhingura ibikoresho bishasha vy’ivyuma bifise atome imwe kandi bitera imbere mu gutahura ingene umuntu yoshobora gutuma ivyuma bikora neza biciye ku ngaruka z’ubufatanye bw’ibibanza vy’ivyuma vy’ubunini butandukanye. Twemera ko iyo nzira ishobora gukoreshwa mu buryo bworoshe ku bindi bikoresho vyinshi vy’ugutuma ibintu bigenda neza.
Ivyo bihimba vy’umubiri vyaguzwe muri McLean, mu Bushinwa. Asidi ya formique (HCOOH, 98%) yaguzwe i Rhawn mu Bushinwa. Ivyo bikoresho vyose vyakoreshwa ata guca ku ruhande ata yindi nzira yo gusukura, kandi amazi asukuye cane yarateguwe hakoreshejwe uburyo bwo gusukura cane. Pt/C (5% y’uburemere bw’ibintu) na Pd/C (5% y’uburemere bw’ibintu) vyaguzwe na Sigma-Aldrich.
Ivyo gukora nanocrystals za CoZn-ZIF vyakozwe bishingiye ku buryo bwa kera hariho n’ibindi vyahinduwe23,64. Ubwa mbere, 30 mmol ya Zn(NO3)2·6H2O (8,925 g) n’3,5 mmol ya Co(NO3)2·6H2O (1,014 g) vyavanzwe maze bivanwa mu militiro 300 z’amazi y’umunyu. Hanyuma, 120 mmol ya 2-methylimidazole (9,853 g) yashizwe mu ml 100 ya methanol, yongerwa ku ntungamubiri iri hejuru. Ivyo bivanze vyari bivuguruwe mu bushuhe bwo mu cumba amasaha 24. Ubwa nyuma, ico kintu caratandukanijwe n’ugucapura ku 6429 g mu minota 10 hanyuma gisukurwa neza n’amazi y’ivyatsi incuro zitatu. Iryo fu ryari rivuyemwo ryumye mu mwuka ku bushuhe bwa 60°C ijoro ryose imbere y’uko rikoreshwa.
Kugira ngo hakorwe Co-SAs/NPs@NC-950, ifu yumye ya CoZn-ZIF yarashizwe ku bushuhe bwa 950 °C mu kiringo c’isaha imwe mu nzira y’umuriro 6% H2 + 94% Ar, n’urugero rw’ubushuhe rwa 5 °C/min. Ico gipimo caciye gikonjeshwa gushika ku bushuhe bwo mu cumba kugira ngo haboneke Co-SA/NPs@NC-950. Ku bihimba vy’umubiri bita Co-SAs/NPs@NC-850 canke Co-SAs/NPs@NC-750, ubushuhe bw’ugusenyuka kw’ibinyabuzima bwahinduwe bushika kuri 850 na 750 °C, uko bikurikirana. Ivyitegererezo vyateguwe birashobora gukoreshwa ata bindi bikoreshwa, nk’ugutera aside.
Ivyo bipimo vya TEM (mikrosikopi y’ubuhinga bwa none) vyakozwe ku gikoresho citwa Thermo Fisher Titan Themis 60-300 “cube” gifise igikoresho co gukosora ukuntu amashusho atari meza be n’igikoresho co gupima igipimo c’ubuhinga bwa 300 kV. Igerageza rya HAADF-STEM ryakozwe hakoreshejwe imikorosikope ya FEI Titan G2 na FEI Titan Themis Z ifise ibikoresho vyo gupima n’ivyo gukosora amashusho, n’ibikoresho vyo gutahura ibintu bifise ibice bine vyitwa DF4. Amashusho y’ikarita y’ibintu vya EDS na yo nyene yararonswe ku gikoresho citwa FEI Titan Themis Z. Isesengurwa rya XPS ryakozwe ku gikoresho co gupima umuco w’izuba (ikigereranyo ca Thermo Fisher ESCALAB 250Xi). Ivyuma vy’imirongo ya XANES na EXAFS Co K-edge vyakoranijwe hakoreshejwe imeza XAFS-500 (Ishirahamwe ry’ibikoresho vy’imirongo y’ibara ry’umuhondo ry’Ubushinwa). Ivyo birimwo vyamenyekanye biciye ku buhinga bwo gupima uburemere bw’ibintu (AAS) (PinAAcle900T). Ivyo bimenyetso vy’imirasire y’izuba (XRD) vyanditswe ku gikoresho co gupima imishwarara y’izuba (Bruker, Bruker D8 Advance, Ubudage). Ivyiyumviro vy’ugufata azote vyaronswe hakoreshejwe igikoresho co gufata azote (Micromeritics, ASAP2020, USA).
Ivyo bikorwa vyo gukuraho amazi mu mazi vyakozwe mu kirere c’argon, umuyaga ukakurwamwo hakurikijwe uburyo bwa Schlenk. Ico gikoresho co gusubiza inyuma carakuwemwo abantu, kigasubira kwuzuzwa argon incuro 6. Hindukiza amazi y’ivyo bikoresho wongeremwo ikintu gitera umuriro (30 mg) n’ikintu gitera umuriro (6 ml). Shusha igikoresho ku bushuhe wipfuza ukoresheje igikoresho co gupima ubushuhe, hanyuma ukireke kibe kiringaniye iminota 30. Hanyuma, aside formique (10 mmol, 377 μL) yongewe mu gitereko c’ivy’ugusubiza munsi ya argon. Hindukiza umupfunda w’ubureti w’inzira zitatu kugira ngo ugabanye umuvuduko mu gikoresho, wongere uwufunge, hanyuma utangure gupima ubunini bwa gazi isohoka ukoresheje uburebure bw’amaboko (Ishusho S16). Inyuma y’igihe gikenewe kugira ngo iyo nzira irangire, haciye hatoranywa ivyerekanwa vya gazi kugira ngo bisuzumwe GC hakoreshejwe urushinge rwo gukingira gazi rwasukuwe n’argon.
Igerageza rya DRIFT ry’aho hantu ryakozwe ku gikoresho co gupima umuco w’izuba (FTIR) (Thermo Fisher Scientific, Nicolet iS50) gifise igikoresho co gutahura umuco w’izuba (MCT). Ifu y’ivyo bihimba vy’umubiri yashizwe mu gice c’umubiri gikora (Ibikoresho vya siyansi vya Harrick, Praying Mantis). Amaze gutera igikoresho gitera umuriro n’umugezi wa Ar (50 ml/min) ku bushuhe bwo mu cumba, ico gipimo carashushe ku bushuhe bumwe, hanyuma gica gipfutse Ar (50 ml/min) mu munyuro wa HCOOH hanyuma gisukwa mu gice c’ihinduka c’aho hantu. kugira ngo umuntu yishure. Ivyitegererezo vy’imigenderanire y’ibintu bitandukanye. Ivyo bimenyetso vy’infrared vyanditswe mu bihe biva ku masegonda 3,0 gushika ku isaha imwe.
HCOOH, DCOOH, HCOOD na DCOOD ni vyo bikoreshwa nk’ibintu bifasha mu gutera ivyatsi vy’ivyatsi vy’ivyatsi. Ivyo bisigaye bihuye n’uburyo bwo gukuraho amazi mu mubiri HCOOH.
Ivyiyumviro vya mbere vy'imibare vyakozwe hakoreshejwe inyigisho y'imikorere y'uburemere mu gisata c'ubuhinga bwa Vienne Ab initio (VASP 5.4.4) 65,66. Igihimba c’umubiri gifise uburebure bwa graphene (5 × 5) gifise uburebure bw’uburebure bw’uburebure bwa 12,5 Å carakoreshejwe nk’igikoresho co gushingirako CoN2C2 na CoN2C2-Co6. Hongeweko urugendo rw’ubusa rurenga 15 Å kugira ngo ntihagire ugukorana hagati y’ibice vy’imbere bifatanye. Ugukorana hagati y'ivyo bita ions n'ivyo bita electrons bidondaguwe n'uburyo bw'umuvuduko w'amazi (PAW)65,67. Hakoreshejwe ubuhinga bwa Perdue-Burke-Ernzerhof (PBE) bwo kwegeranya urugero rusangi (GGA) n’ugukosora kwa van der Waals kwashikirijwe na Grimm68,69. Ivyiyumviro vy’uguhuza inguvu n’inguvu vyose ni 10−6 eV/atome na 0.01 eV/Å. Inguvu zigabanywa zashizwe ku 600 eV hakoreshejwe uruzitiro rw’intonde 2 × 2 × 1 rwa Monkhorst-Pack. Igikoresho c’ubuhinga bw’ikinyoma gikoreshwa muri iki kigereranyo cubatswe kuva ku ntunganyo y’ubuhinga bwa none gushika mu rwego rwa C 2s22p2, rwego rwa N 2s22p3, rwego rwa Co 3d74s2, rwego rwa H 1 s1, n’urwego rwa O 2s22p4. Inguvu z’ugufata n’itandukaniro ry’uburemere bw’ama elegitoro biharurwa mu kugabanya inguvu z’inzira ya gazi n’ubwoko bwo ku ruhande ku nguvu z’urutonde rw’ugufata hakurikijwe uburyo bwo gufata canke bw’imirongo70,71,72,73,74. Igikosora c’inguvu z’ubuntu ca Gibbs gikoreshwa mu guhindura inguvu za DFT mu nguvu z’ubuntu za Gibbs kandi kizirikana intererano z’ugunyiganyiga ku ntungamubiri n’inguvu z’intangamarara75. Uburyo bwo gutera ishusho-nudging band (CI-NEB) bwakoreshejwe mu kurondera ivy'uguhinduka kw'inyishu76.
Amakuru yose yaronswe kandi asesengurwa muri iki cigwa ashirwa mu ngingo no mu bikoresho vy’inyongera canke araboneka ku mwanditsi abifitiye uburenganzira iyo asavye. Amakuru y’inkomoko aratanzwe muri iyi ngingo.
Kode yose yakoreshejwe mu bigereranyo biherekejwe n’iki kiganiro iraboneka ku banditsi babihuye iyo ubisavye.
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