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Ci gaban fasahar hydrogen yana cikin zuciyar tattalin arzikin kore. A matsayin wani sharaɗi na gaba don cimma ajiyar hydrogen, ana buƙatar masu haɓaka aiki da karko don amsawar hydrogenation (de) hydrogenation. Har zuwa yanzu, wannan yanki ya mamaye ta hanyar amfani da ƙarfe masu tsada masu tsada. A nan, muna ba da shawarar sabon mai haɓaka cobalt mai rahusa (Co-SAs/NPs@NC) inda wuraren ƙarfe guda ɗaya da aka rarraba sosai aka haɗa su tare da ƙananan ƙwayoyin cuta don cimma ingantaccen ragewar formic acid. Ta amfani da mafi kyawun kayan na'urorin CoN2C2 da aka watsa ta atomic da ƙananan ƙwayoyin nanoparticles masu girman 7-8 nm, ta amfani da propylene carbonate azaman mai narkewa, an sami kyakkyawan samar da iskar gas na 1403.8 ml g-1 h-1, kuma babu asara bayan zagayowar 5. aiki, wanda ya fi sau 15 kyau fiye da Pd/C na kasuwanci. Gwaje-gwajen gwaji a wurin sun nuna cewa, idan aka kwatanta da ƙwayoyin ƙarfe guda ɗaya da na nanoparticle masu alaƙa, Co-SAs/NPs@NC suna haɓaka shaƙatawa da kunna maɓallin monodentate matsakaiciyar HCOO*, ta haka suna haɓaka raba haɗin CH na gaba. Lissafin ka'idoji sun nuna cewa haɗa ƙwayoyin cobalt yana haɓaka juyawar cibiyar d-band na ƙwayar Co guda ɗaya zuwa wurin aiki, ta haka yana haɓaka haɗin gwiwa tsakanin carbonyl O na tsaka-tsakin HCOO* da cibiyar Co, ta haka yana rage shingen makamashi.
Ana ɗaukar hydrogen a matsayin muhimmin mai ɗaukar makamashi don sauyin makamashi na duniya a yanzu kuma yana iya zama babban abin da ke haifar da cimma daidaiton carbon1. Saboda halayensa na zahiri kamar ƙarfin ƙonewa da ƙarancin yawa, ajiyarsa mai aminci da inganci da jigilar hydrogen sune manyan batutuwa wajen cimma tattalin arzikin hydrogen2,3,4. An gabatar da masu ɗaukar hydrogen na ruwa (LOHCs), waɗanda ke adanawa da sakin hydrogen ta hanyar halayen sinadarai, a matsayin mafita. Idan aka kwatanta da hydrogen na kwayoyin halitta, irin waɗannan abubuwa (methanol, toluene, dibenzyltoluene, da sauransu) suna da sauƙin sarrafawa5,6,7. Daga cikin LOHCs na gargajiya daban-daban, formic acid (FA) yana da ƙarancin guba (LD50: 1.8 g/kg) da ƙarfin H2 na 53 g/L ko 4.4 wt%. Abin lura, FA ita ce kawai LOHC da za ta iya adanawa da sakin hydrogen a ƙarƙashin yanayi mai sauƙi a gaban masu haɓaka kuzari masu dacewa, don haka ba ta buƙatar manyan shigarwar makamashi na waje1,8,9. A gaskiya ma, an ƙirƙiro da yawa daga cikin ƙwayoyin ƙarfe masu daraja don rage sinadarin formic acid, misali, ƙwayoyin da ke tushen palladium sun fi ƙarfin ƙarfe masu rahusa sau 50-200 sau 10,11,12. Duk da haka, idan aka yi la'akari da farashin ƙarfe masu aiki, misali, palladium ya fi tsada sau 1000.
Cobalt, Neman abubuwan kara kuzari masu ƙarfi da karko na ƙarfe iri-iri yana ci gaba da jan hankalin masu bincike da yawa a fannin ilimi da masana'antu13,14,15.
Duk da cewa an samar da na'urori masu araha waɗanda suka dogara da Mo da Co, da kuma nanocatalysts da aka yi daga ƙarfe mai daraja/tushe, 14,16 don rage yawan sinadarin FA, rage yawan sinadarin su a hankali yayin aikin ba makawa saboda mamaye wuraren aiki na ƙarfe, CO2, da H2O ta hanyar protons. ko formate anions (HCOO-), gurɓatar FA, tarin ƙwayoyin cuta da yiwuwar gubar CO17,18. Mu da wasu kwanan nan mun nuna cewa na'urori masu haɓaka sinadarin atom guda ɗaya (SACs) tare da wuraren CoIINx da aka warwatse sosai a matsayin wuraren aiki suna inganta amsawa da juriyar acid na rage sinadarin formic acid idan aka kwatanta da nanoparticles17,19,20,21,22,23,24. A cikin waɗannan kayan Co-NC, na'urorin N suna aiki a matsayin manyan wurare don haɓaka rage sinadarin FA yayin da suke haɓaka daidaiton tsarin ta hanyar haɗin gwiwa da na'urorin Co-NC na tsakiya, yayin da na'urorin Co ke samar da wuraren shaye-shaye na H kuma suna haɓaka yankewar CH22, 25,26. Abin takaici, ayyukan da kwanciyar hankalin waɗannan abubuwan ƙarfafawa har yanzu ba su da alaƙa da na zamani masu kama da juna da kuma masu haɗakar ƙarfe masu daraja (Hoto na 1) 13.
Ana iya samar da makamashi mai yawa daga tushen sabuntawa kamar hasken rana ko iska ta hanyar amfani da electrolysis na ruwa. Ana iya adana hydrogen da aka samar ta amfani da LOHC, wani ruwa wanda hydrogenation da dehydrogenation za a iya mayar da su. A matakin dehydrogenation, samfurin kawai shine hydrogen, kuma ruwan da ke ɗauke da shi ana mayar da shi zuwa yanayinsa na asali kuma a sake haɗa shi da hydrogen. Daga ƙarshe ana iya amfani da hydrogen a tashoshin mai, batura, gine-ginen masana'antu, da sauransu.
Kwanan nan, an ruwaito cewa ana iya inganta ayyukan SAC na musamman idan aka samu ƙwayoyin ƙarfe daban-daban ko ƙarin wuraren ƙarfe da nanoparticles (NPs) ko nanoclusters (NCs) ke bayarwa. Wannan yana buɗe damar ƙarin shawa da kunna substrate, da kuma daidaita yanayin ƙasa da tsarin lantarki na wuraren monatomic. Ta wannan hanyar, ana iya inganta shawa/kunna substrate, yana samar da ingantaccen ingancin catalytic gaba ɗaya29,30. Wannan yana ba mu ra'ayin ƙirƙirar kayan catalytic masu dacewa tare da wuraren aiki na hybrid. Kodayake ingantattun SACs sun nuna babban iko a cikin nau'ikan aikace-aikacen catalytic iri-iri31,32,33,34,35,36, gwargwadon iliminmu, rawar da suke takawa a cikin ajiyar hydrogen ba ta da tabbas. Dangane da wannan, muna ba da rahoton wata dabara mai amfani da ƙarfi don haɗa abubuwan catalysts na hybrid na tushen cobalt (Co-SAs/NPs@NCs) waɗanda suka ƙunshi nanoparticles da aka ƙayyade da cibiyoyin ƙarfe na mutum ɗaya. An inganta Co-SAs/NPs@NC suna nuna kyakkyawan aikin dehydrogenation na formic acid, wanda ya fi nanostructured catalists marasa daraja (kamar CoNx, cobalt atom guda ɗaya, cobalt@NC da γ-Mo2N) har ma da noble metal catalists. Halayyar In-situ da lissafin DFT na masu aiki catalists sun nuna cewa kowane rukunin ƙarfe yana aiki azaman wuraren aiki, kuma nanoparticles na wannan ƙirƙira suna haɓaka cibiyar d-band na atoms na Co, suna haɓaka shaye-shaye da kunna HCOO*, ta haka suna rage shingen makamashi na amsawar.
Tsarin Zeolite imidazolate (ZIFs) sune abubuwan da aka tsara musamman don samar da abubuwan kara kuzari ga kayan carbon da aka yi amfani da nitrogen (masu kara kuzari na ƙarfe-NC) don tallafawa nau'ikan karafa daban-daban37,38. Saboda haka, Co(NO3)2 da Zn(NO3)2 suna haɗuwa da 2-methylimidazole a cikin methanol don samar da hadaddun ƙarfe masu dacewa a cikin maganin. Bayan centrifugation da bushewa, an sanya CoZn-ZIF a cikin yanayin zafi daban-daban (750–950 °C) a cikin yanayi na 6% H2 da 94% Ar. Kamar yadda aka nuna a cikin hoton da ke ƙasa, kayan da aka samo suna da halaye daban-daban na wurin aiki kuma an sanya musu suna Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750 (Hoto na 2a). ) . An yi cikakken bayani game da takamaiman gwaje-gwaje na wasu matakai masu mahimmanci a cikin tsarin hadawa a cikin Hoto na 1 da 2. C1-C3. An yi gwajin X-ray diffraction (VTXRD) mai yanayin zafi mai canzawa don sa ido kan juyin halittar mai kara kuzari. Da zarar zafin pyrolysis ya kai 650 °C, tsarin XRD yana canzawa sosai saboda rugujewar tsarin lu'ulu'u da aka tsara na ZIF (Hoto na S4) 39. Yayin da zafin ya ƙara ƙaruwa, manyan kololuwa guda biyu suna bayyana a cikin tsarin XRD na Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750 a 20-30 ° da 40-50 °, suna wakiltar kololuwar carbon mara tsari (Hoto na C5). 40. Ya kamata a lura cewa kololuwa uku ne kawai aka lura a 44.2 °, 51.5 ° da 75.8 °, mallakar cobalt na ƙarfe (JCPDS #15-0806), da 26.2 °, mallakar carbon graphitic (JCPDS # 41-1487). Tsarin X-ray na Co-SAs/NPs@NC-950 yana nuna kasancewar ƙwayoyin cobalt masu kama da graphite a kan catalyst41,42,43,44. Tsarin Raman ya nuna cewa Co-SAs/NPs@NC-950 ya bayyana yana da mafi ƙarfi da kunkuntar kololuwar D da G fiye da sauran samfuran, wanda ke nuna matakin graphitization mafi girma (Hoto na S6). Bugu da ƙari, Co-SAs/NPs@NC-950 yana nuna mafi girman yankin saman Brunner-Emmett-Taylor (BET) da girman rami (1261 m2 g-1 da 0.37 cm3 g-1) fiye da sauran samfura kuma yawancin ZIFs kayan NC ne (Hoto na S7 da Tebur S1). Binciken shaye-shayen kwayoyin halitta (AAS) ya nuna cewa sinadarin cobalt na Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 da Co-SAs/NPs@ shine 2.69 wt.%, 2.74 wt.% da 2.73 wt.%. NC-750 bi da bi (Tebur S2). Yawan sinadarin Zn na Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750 yana ƙaruwa a hankali, wanda aka danganta da ƙaruwar raguwa da raguwar raka'o'in Zn. Ƙara yawan zafin pyrolysis (Zn, wurin tafasa = 907 °C) 45.46. Binciken abubuwa (EA) ya nuna cewa kashi na N yana raguwa tare da ƙaruwar zafin pyrolysis, kuma babban abun ciki na O na iya zama saboda shaƙar kwayoyin halitta O2 daga fallasa zuwa iska. (Tebur S3). A wani adadin sinadarin cobalt, ƙwayoyin nanoparticles da kuma ƙwayoyin da aka ware suna rayuwa tare, wanda ke haifar da ƙaruwa mai yawa a cikin ayyukan haɓaka aiki, kamar yadda aka tattauna a ƙasa.
Zane mai tsari na haɗa Co-SA/NPs@NC-T, inda T shine zafin pyrolysis (°C). b Hoton TEM. c Hoton Co-SAs/NPs@NC-950 AC-HAADF-STEM. Ana yiwa atom ɗin Co guda ɗaya alama da da'irori ja. d Tsarin EDS na Co-SA/NPs@NC-950.
Abin lura shi ne, na'urar auna karfin lantarki ta watsawa (TEM) ta nuna kasancewar nau'ikan nanoparticles na cobalt (NPs) daban-daban tare da matsakaicin girman 7.5 ± 1.7 nm kawai a cikin Co-SAs/NPs@NC-950 (Figures 2b da S8). Waɗannan nanoparticles an lulluɓe su da carbon mai kama da graphite wanda aka haɗa da nitrogen. Tazarar layin layi na 0.361 da 0.201 nm ya yi daidai da barbashi na carbon graphitic (002) da na ƙarfe na Co (111), bi da bi. Bugu da ƙari, na'urar auna karfin lantarki ta hanyar amfani da babban kusurwa mai gyarawa (AC-HAADF-STEM) ta nuna cewa Co NPs a cikin Co-SAs/NPs@NC-950 suna kewaye da yawan cobalt na atomic (Hoto na 2c). Duk da haka, an lura da ƙwayoyin cobalt da aka watsa ta atomic kawai akan goyon bayan sauran samfuran guda biyu (Hoto na S9). Hoton HAADF-STEM na watsawa ta makamashi (EDS) yana nuna rarrabawar C, N, Co da Co NPs daban-daban a cikin Co-SAs/NPs@NC-950 (Hoto na 2d). Duk waɗannan sakamakon sun nuna cewa cibiyoyin Co da aka watsa ta atomatik da ƙananan ƙwayoyin cuta da aka lulluɓe a cikin carbon mai kama da N-doped an haɗa su cikin nasara zuwa substrates na NC a cikin Co-SAs/NPs@NC-950, yayin da cibiyoyin ƙarfe kawai aka keɓe.
An yi nazarin yanayin valence da kuma sinadaran kayan da aka samu ta hanyar amfani da na'urar daukar hoto ta X-ray photoelectron spectroscopy (XPS). Siffar XPS na abubuwan kara kuzari guda uku sun nuna kasancewar abubuwan Co, N, C da O, amma Zn yana nan ne kawai a cikin Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750 (Hoto na 2). ). C10). Yayin da zafin pyrolysis ke ƙaruwa, jimlar abun cikin nitrogen yana raguwa yayin da nau'ikan nitrogen suka zama marasa ƙarfi kuma suka ruɓe zuwa iskar gas ta NH3 da NOx a yanayin zafi mafi girma (Tebur S4) 47. Don haka, jimlar abun cikin carbon ya ƙaru a hankali daga Co-SAs/NPs@NC-750 zuwa Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-950 (Figures S11 da S12). Samfurin da aka lalata a zafin jiki mafi girma yana da ƙarancin rabo na atom na nitrogen, wanda ke nufin cewa adadin masu ɗaukar NC a cikin Co-SAs/NPs@NC-950 ya kamata ya zama ƙasa da na sauran samfuran. Wannan yana haifar da ƙara yawan sinadarin cobalt. Bakan O1s yana nuna kololuwa biyu na C=O (531.6 eV) da C–O (533.5 eV), bi da bi (Hoto na S13) 48. Kamar yadda aka nuna a Hoto na 2a, ana iya warware bakan N1s zuwa kololuwa huɗu na halayen pyridine nitrogen N (398.4 eV), pyrrole N (401.1 eV), graphite N (402.3 eV) da Co-N (399.2 eV). Haɗin Co-N yana nan a cikin dukkan samfuran uku, yana nuna cewa wasu ƙwayoyin N suna haɗuwa zuwa wuraren monometallic, amma halayen sun bambanta sosai49. Amfani da zafin jiki mafi girma na pyrolysis na iya rage yawan abubuwan da ke cikin nau'in Co-N daga 43.7% a cikin Co-SA/NPs@NC-750 zuwa 27.0% a cikin Co-SAs/NPs@NC-850 da Co 17.6%@ NC-950. a cikin -CA/NPs, wanda yayi daidai da ƙaruwar abun ciki na C (Hoto na 3a), yana nuna cewa adadin haɗin gwiwar Co-N nasu na iya canzawa kuma a maye gurbinsu da ƙwayoyin C50 kaɗan. Tsarin Zn 2p ya nuna cewa wannan sinadari yana wanzuwa galibi a cikin nau'in Zn2+. (Hoto na S14) 51. Tsarin Co 2p yana nuna manyan kololuwa guda biyu a 780.8 da 796.1 eV, waɗanda aka danganta su da Co 2p3/2 da Co 2p1/2, bi da bi (Hoto na 3b). Idan aka kwatanta da Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750, an canza kololuwar Co-N a cikin Co-SAs/NPs@NC-950 zuwa gefen da ya dace, yana nuna cewa atom ɗin Co guda ɗaya zuwa saman -SAs/NPs@NC-950 yana da matakin raguwar electron mafi girma, wanda ke haifar da yanayin iskar shaka. Ya kamata a lura cewa Co-SAs/NPs@NC-950 ne kawai suka nuna raunin kololuwar sifili-valent cobalt (Co0) a 778.5 eV, wanda ke tabbatar da wanzuwar ƙwayoyin nanoparticles sakamakon tarin cobalt SA a yanayin zafi mai yawa.
a N 1s da b Co 2p spectra na Co-SA/NPs@NC-T. c XANES da d FT-EXAFS spectra na Co-K-gefen Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750. e WT-EXAFS plans na Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850, da Co-SAs/NPs@NC-750. f FT-EXAFS line fitting language for Co-SA/NPs@NC-950.
An yi amfani da na'urar X-ray absorption spectroscopy (XAS) mai kulle lokaci don nazarin tsarin lantarki da yanayin daidaitawa na nau'in Co a cikin samfurin da aka shirya. Yanayin valence na Cobalt a cikin tsarin Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 da tsarin Co-SAs/NPs@NC-750 Edge wanda aka bayyana ta hanyar daidaita sha X-ray kusa da filin a gefen Co-K (XANES). Kamar yadda aka nuna a Hoto na 3c, sha kusa da gefen samfuran uku yana tsakanin foils na Co da CoO, yana nuna cewa yanayin valence na nau'in Co yana tsakanin 0 zuwa +253. Bugu da ƙari, an lura da sauyawa zuwa ƙarancin kuzari daga Co-SAs/NPs@NC-950 zuwa Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750, yana nuna cewa Co-SAs/NPs@NC-750 yana da ƙarancin yanayin oxidation. Jerin juyawa. Dangane da sakamakon haɗakar layi, an kiyasta yanayin Covalence na Co-SAs/NPs@NC-950 ya kai +0.642, wanda ya yi ƙasa da yanayin Covalence na Co-SAs/NPs@NC-850 (+1.376). Co-SA/NP @NC-750 (+1.402). Waɗannan sakamakon sun nuna cewa matsakaicin yanayin oxidation na ƙwayoyin cobalt a cikin Co-SAs/NPs@NC-950 ya ragu sosai, wanda ya yi daidai da sakamakon XRD da HADF-STEM kuma ana iya bayyana shi ta hanyar kasancewa tare da ƙwayoyin cobalt da cobalt guda ɗaya. . Atoms na Co 41. Tsarin ɗaukar hasken X-ray mai kyau na Fourier transform (FT-EXAFS) na Co-gefen yana nuna cewa babban kololuwar da ke 1.32 Å na cikin harsashin Co-N/Co-C ne, yayin da hanyar watsawa ta ƙarfe Co-Co yana a 2.18 kawai a cikin Co-SAs Å da aka samo a cikin /NPs@NC-950 (Hoto na 3d). Bugu da ƙari, taswirar canjin wavelet (WT) tana nuna matsakaicin ƙarfin a 6.7 Å-1 da aka danganta ga Co-N/Co-C, yayin da Co-SAs/NPs@NC-950 kawai ke nuna matsakaicin ƙarfin da aka danganta ga 8.8. Wani matsakaicin ƙarfin yana a Å−1 zuwa haɗin Co-Co (Hoto na 3e). Bugu da ƙari, binciken EXAFS da mai haya ya yi ya nuna cewa a yanayin zafi na pyrolysis na 750, 850 da 950 °C, lambobin daidaitawa na Co-N sun kasance 3.8, 3.2 da 2.3, bi da bi, kuma lambobin daidaitawa na Co-C sun kasance 0. 0.9 da 1.8 (Hoto na 3f, S15 da Tebur S1). Musamman ma, sakamakon da aka samu kwanan nan za a iya danganta shi da kasancewar raka'o'in CoN2C2 da nanoparticles da aka watsa ta atomic a cikin Co-SAs/NPs@NC-950. Sabanin haka, a cikin Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750, raka'o'in CoN3C da CoN4 ne kawai ke nan. A bayyane yake cewa tare da ƙaruwar zafin pyrolysis, ana maye gurbin atom na N a cikin naúrar CoN4 a hankali da atom na C, da kuma attachments na cobalt CA don samar da nanoparticles.
An yi amfani da yanayin amsawar da aka yi nazari a baya don nazarin tasirin yanayin shiri akan halayen kayan aiki daban-daban (Hoto na S16)17,49. Kamar yadda aka nuna a Hoto na 4 a, aikin Co-SAs/NPs@NC-950 ya fi na Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750 girma sosai. Abin lura shi ne, dukkan samfuran Co guda uku da aka shirya sun nuna kyakkyawan aiki idan aka kwatanta da na'urorin haɓaka ƙarfe masu daraja na kasuwanci (Pd/C da Pt/C). Bugu da ƙari, samfuran Zn-ZIF-8 da Zn-NC ba su da aiki don rage sinadarin acid na formic, wanda ke nuna cewa ƙwayoyin Zn ba wuraren aiki ba ne, amma tasirinsu akan aikin ba shi da yawa. Bugu da ƙari, aikin Co-SAs/NPs@NC-850 da Co-SAs/NPs@NC-750 sun sami pyrolysis na biyu a 950°C na tsawon awa 1, amma ya yi ƙasa da na Co-SAs/NPs@NC-750. @NC-950 (Hoto na S17). Siffar tsarin waɗannan kayan ta nuna kasancewar ƙwayoyin Co a cikin samfuran da aka sake yin pyrolyzed, amma ƙarancin yanki na musamman da rashin carbon mai kama da graphite ya haifar da ƙarancin aiki idan aka kwatanta da Co-SAs/NPs@NC-950 (Hoto na S18–S20). An kuma kwatanta ayyukan samfuran tare da adadin Co precursor daban-daban, tare da mafi girman aikin da aka nuna a ƙarin mol 3.5 (Tebur S6 da Hoto na S21). A bayyane yake cewa samuwar cibiyoyin ƙarfe daban-daban yana da tasiri ta hanyar abubuwan da ke cikin hydrogen a cikin yanayin pyrolysis da lokacin pyrolysis. Saboda haka, an kimanta wasu kayan Co-SAs/NPs@NC-950 don aikin dehydrogenation na formic acid. Duk kayan sun nuna matsakaicin aiki zuwa kyakkyawan aiki; duk da haka, babu ɗayansu da ya fi Co-SAs/NPs@NC-950 kyau (Hoto na S22 da S23). Tsarin siffanta kayan ya nuna cewa tare da ƙaruwar lokacin pyrolysis, abubuwan da ke cikin matsayin monoatomic Co-N suna raguwa a hankali saboda tarin ƙwayoyin ƙarfe zuwa ƙananan ƙwayoyin cuta, wanda ke bayyana bambancin aiki tsakanin samfuran da ke da lokacin pyrolysis na 100-2000. bambanci. 0.5 hours, 1 hours, da 2 hours (Figures S24–S28 da Tebur S7).
Jadawalin girman iskar gas idan aka kwatanta da lokacin da aka samu yayin cire sinadarin hydrogen daga cikin man fetur ta amfani da sinadarai daban-daban. Yanayin amsawa: PC (10 mmol, 377 μl), mai kara kuzari (30 mg), PC (6 ml), Tback: 110 °C, Dabaru: 98 °C, sassa 4 b Co-SAs/NPs@NC-950 (30 mg), sinadarai daban-daban. c Kwatanta yawan juyin halittar iskar gas na masu kara kuzari daban-daban a cikin sinadarai masu narkewa a 85–110 °C. d Gwajin sake amfani da Co-SA/NPs@NC-950. Yanayin amsawa: FA (10 mmol, 377 µl), Co-SAs/NPs@NC-950 (30 mg), mai kara kuzari (6 ml), Tset: 110 °C, Dabaru: 98 °C, kowane zagayen amsawa yana ɗaukar awa ɗaya. Sandunan kuskure suna wakiltar karkacewar da aka ƙididdige daga gwaje-gwaje uku masu aiki.
Gabaɗaya, ingancin abubuwan da ke haifar da rage yawan sinadarin hydrogenation na FA ya dogara sosai akan yanayin amsawar, musamman sinadarin da aka yi amfani da shi a matsayin mai narkewa, Co-SAs/NPs@NC-950 ya nuna mafi girman ƙimar amsawar farko, amma kashewa ya faru, wataƙila saboda protons ko H2O18 da ke mamaye wuraren aiki. Gwajin mai haifar da sinadarin fluidation a cikin abubuwan da ke haifar da sinadarai kamar 1,4-dioxane (DXA), n-butyl acetate (BAC), toluene (PhMe), triglyme da cyclohexanone (CYC) suma bai nuna wani ci gaba ba, kuma a cikin propylene carbonate (PC) ) (Hoto na 4b da Tebur S8). Haka kuma, ƙarin abubuwa kamar triethylamine (NET3) ko sodium formate (HCCONa) ba su da wani ƙarin tasiri mai kyau akan aikin mai haifar da sinadarai (Hoto na S29). A ƙarƙashin yanayin amsawa mafi kyau, yawan iskar gas ɗin ya kai 1403.8 mL g−1 h−1 (Hoto na S30), wanda ya fi duk abubuwan da aka ruwaito a baya na Co catalyst (gami da SAC17, 23, 24). A cikin gwaje-gwaje daban-daban, ban da halayen da ke cikin ruwa da kuma tare da ƙarin abubuwa, an sami zaɓuɓɓukan dehydrogenation da dehydration na har zuwa 99.96% (Tebur S9). Ƙarfin kunnawa da aka ƙididdige shine 88.4 kJ/mol, wanda yayi daidai da ƙarfin kunnawa na masu haɓaka ƙarfe masu daraja (Hoto na S31 da Tebur S10).
Bugu da ƙari, mun kwatanta wasu ƙarin abubuwan kara kuzari daban-daban don rage sinadarin acid a ƙarƙashin irin wannan yanayi (Hoto na 4c, tebura S11 da S12). Kamar yadda aka nuna a Hoto na 3c, yawan samar da iskar gas na Co-SAs/NPs@NC-950 ya wuce na mafi yawan sanannun masu kara kuzari na ƙarfe masu tushe daban-daban kuma ya ninka sau 15 da 15 fiye da na kasuwanci na 5% Pd/C da 5% Pd/C, bi da bi, da sau 10. % Pt/C mai kara kuzari.
Muhimmin fasali na duk wani amfani da sinadarai masu rage yawan sinadarin hydrogenation shine kwanciyar hankalinsu. Saboda haka, an gudanar da gwaje-gwajen sake amfani da su ta amfani da Co-SAs/NPs@NC-950. Kamar yadda aka nuna a Hoto na 4 d, aikin farko da zaɓin kayan sun kasance ba su canza ba a cikin gudu biyar a jere (duba kuma Tebur S13). An gudanar da gwaje-gwaje na dogon lokaci kuma samar da iskar gas ya ƙaru a layi a cikin awanni 72 (Hoto na S32). Yawan sinadarin cobalt na Co-SA/NPs@NC-950 da aka yi amfani da shi ya kai 2.5 wt%, wanda ya yi kusa da na sabon sinadarin, wanda ke nuna cewa babu wani haske na cobalt (Tebur S14). Ba a lura da canjin launi ko tarin ƙwayoyin ƙarfe ba kafin da kuma bayan amsawar (Hoto na S33). AC-HAADF-STEM da EDS na kayan da aka yi amfani da su a cikin gwaje-gwajen dogon lokaci sun nuna riƙewa da watsawa iri ɗaya na wuraren watsawar atomic kuma babu manyan canje-canje na tsari (Hoto na S34 da S35). Har yanzu akwai kololuwar halayyar Co0 da Co-N a cikin XPS, wanda ke tabbatar da kasancewar Co NPs da wuraren ƙarfe daban-daban, wanda kuma ya tabbatar da daidaiton Co-SAs/NPs@NC-950 catalyst (Hoto na S36).
Domin gano wuraren da suka fi aiki da ke da alhakin lalata sinadarin formic acid, an shirya kayan da aka zaɓa waɗanda ke da cibiyar ƙarfe ɗaya kawai (CoN2C2) ko Co NP bisa ga binciken da aka yi a baya17. Tsarin aikin lalata sinadarin formic acid da aka lura a ƙarƙashin yanayi iri ɗaya shine Co-SAs/NPs@NC-950 > Co SA > Co NP (Tebur S15), yana nuna cewa wuraren CoN2C2 da aka watsa ta atomatik sun fi NPs aiki. Kinetics na amsawa sun nuna cewa juyin halittar hydrogen yana bin kinetics na amsawa na farko, amma gangaren lanƙwasa da yawa a cikin abubuwan da ke cikin cobalt daban-daban ba iri ɗaya ba ne, yana nuna cewa kinetics ba ya dogara ne kawai akan formic acid ba, har ma da wurin aiki (Hoto na 2). C37). Ƙarin nazarin kinetics sun nuna cewa, idan aka yi la'akari da rashin kololuwar ƙarfe na cobalt a cikin nazarin diffraction na X-ray, an gano cewa tsarin kinetic na amsawar dangane da abun cikin cobalt ya kasance 1.02 a ƙananan matakan (ƙasa da 2.5%), yana nuna kusan rarrabawar cibiyoyin cobalt monoatomic kusan iri ɗaya. main. wurin aiki (figs. S38 da S39). Lokacin da abun cikin ƙwayoyin Co ya kai 2.7%, r ya ƙaru ba zato ba tsammani, yana nuna cewa ƙwayoyin nano suna hulɗa sosai da ƙwayoyin halitta daban-daban don samun ƙarin aiki. Yayin da abun cikin ƙwayoyin Co ke ƙaruwa, lanƙwasa ya zama mara layi, wanda ke da alaƙa da ƙaruwar adadin ƙwayoyin nano da raguwar matsayin monatomic. Don haka, ingantaccen aikin dehydrogenation na LC na Co-SA/NPs@NC-950 yana faruwa ne daga halayen haɗin gwiwa na wuraren ƙarfe da ƙwayoyin nano.
An gudanar da wani bincike mai zurfi ta amfani da in situ diffuse reflectance Fourier transform (in situ DRIFT) don gano tsaka-tsakin amsawa a cikin aikin. Bayan dumama samfuran zuwa yanayin zafi daban-daban bayan ƙara formic acid, an lura da saitin mitoci guda biyu (Hoto na 5a). Kololuwar halaye guda uku na HCOOH* sun bayyana a 1089, 1217 da 1790 cm-1, waɗanda aka danganta da girgizar CH π (CH) ta waje, girgizar CO ν (CO) da girgizar C=O ν (C=O) ta waje, 54, 55 bi da bi. Wani saitin kololuwa a 1363 da 1592 cm-1 ya yi daidai da girgizar OCO mai daidaituwa νs (OCO) da girgizar OCO mai asymmetric νas (OCO)33.56 HCOO*, bi da bi. Yayin da amsawar ke ci gaba, kololuwar dangi na nau'in HCOOH* da HCOO* suna ɓacewa a hankali. Gabaɗaya dai, rugujewar formic acid ya ƙunshi manyan matakai guda uku: (I) shaƙar formic acid a wuraren aiki, (II) cire H ta hanyar format ko carboxylate, da kuma (III) haɗin H guda biyu masu sha don samar da hydrogen. HCOO* da COOH* su ne manyan hanyoyin da ke tantance hanyoyin format ko carboxylate, bi da bi57. Ta amfani da tsarin catalytic ɗinmu, ƙwanƙolin HCOO* na musamman ya bayyana, wanda ke nuna cewa rugujewar formic acid yana faruwa ne kawai ta hanyar formic acid58. An yi irin wannan lura a ƙananan yanayin zafi na 78 °C da 88 °C (hoto na S40).
A cikin yanayin DRIFT na dehydrogenation na HCOOH akan Co-SAs/NPs@NC-950 da b Co SAs. Tatsuniya tana nuna lokutan amsawa a wurin. c Bambancin yawan iskar gas da aka samar ta amfani da ma'aikatan lakabi daban-daban na isotope akan lokaci. d Bayanan tasirin isotope na Kinetic.
An gudanar da gwaje-gwaje makamancin haka a wurin Co NP da Co SA don nazarin tasirin haɗin gwiwa a cikin Co-SA/NPs@NC-950 (Hotuna 5 b da S41). Duk kayan suna nuna irin wannan yanayin, amma kololuwar halayen HCOOH* da HCOO* an ɗan canza su kaɗan, yana nuna cewa gabatar da Co NPs yana canza tsarin lantarki na cibiyar monoatomic. Kololuwar halayyar νas(OCO) ta bayyana a cikin Co-SAs/NPs@NC-950 da Co SA amma ba a cikin Co NPs ba, wanda hakan ke nuna cewa matsakaicin da aka samar bayan ƙara formic acid shine monodentate formic acid wanda ke tsaye a saman gishirin jirgin sama. kuma an lulluɓe shi a kan SA a matsayin wurin aiki 59. Ya kamata a lura cewa an lura da ƙaruwa mai yawa a cikin rawar jiki na kololuwar halayyar π(CH) da ν(C = O), wanda a bayyane ya haifar da karkacewar HCOOH* kuma ya sauƙaƙa amsawar. Sakamakon haka, kololuwar halayen HCOOH* da HCOO* a cikin Co-SAs/NPs@NC kusan sun ɓace bayan mintuna 2 na amsawa, wanda ya fi sauri fiye da na monometallic (minti 6) da nanoparticle-based catalysts (minti 12). Duk waɗannan sakamakon sun tabbatar da cewa maganin nanoparticle yana haɓaka shaye-shaye da kunna tsaka-tsaki, ta haka yana hanzarta halayen da aka gabatar a sama.
Don ƙarin nazarin hanyar amsawa da kuma tantance matakin tantance ƙimar (RDS), an gudanar da tasirin KIE a gaban Co-SAs/NPs@NC-950. A nan, ana amfani da isotopes daban-daban na formic acid kamar HCOOH, HCOOD, DCOOH da DCOOD don nazarin KIE. Kamar yadda aka nuna a Hoto na 5c, ƙimar dehydrogenation ta ragu a cikin tsari mai zuwa: HCOOH > HCOOD > DCOOH > DCOOD. Bugu da ƙari, an ƙididdige ƙimar KHCOOH/KHCOOD, KHCOOH/KDCOOH, KHCOOD/KDCOOD da KDCOOH/KDCOOD a matsayin 1.14, 1.71, 2.16 da 1.44, bi da bi (Hoto na 5d). Saboda haka, rabuwar haɗin CH a cikin HCOO* yana nuna ƙimar kH/kD >1.5, yana nuna babban tasirin motsi60,61, kuma da alama yana wakiltar RDS na dehydrogenation na HCOOH akan Co-SAs/NPs@NC-950.
Bugu da ƙari, an yi lissafin DFT don fahimtar tasirin ƙwayoyin nano da aka yi amfani da su a cikin aikin Co-SA. An gina samfuran Co-SAs/NPs@NC da Co-SA bisa ga gwaje-gwajen da aka nuna da ayyukan da suka gabata (Hoto na 6a da S42)52,62. Bayan inganta yanayin lissafi, an gano ƙananan ƙwayoyin nano6 na Co6 (CoN2C2) waɗanda ke rayuwa tare da raka'o'in monoatomic, kuma an ƙaddara tsawon haɗin Co-C da Co-N a cikin Co-SA/NPs@NC ya zama 1.87 Å da 1.90 Å, bi da bi. , wanda ya yi daidai da sakamakon XAFS. Yawan yanki na jihohi da aka ƙididdige (PDOS) ya nuna cewa ƙwayar ƙarfe guda ɗaya ta Co da haɗin nanoparticle (Co-SAs/NPs@NC) suna nuna haɗuwa mafi girma kusa da matakin Fermi idan aka kwatanta da CoN2C2, wanda ya haifar da HCOOH. Canja wurin lantarki da aka ruɓe ya fi inganci (Hoto na 6b da S43). An ƙididdige cibiyoyin d-band masu dacewa na Co-SAs/NPs@NC da Co-SA zuwa -0.67 eV da -0.80 eV, bi da bi, daga cikinsu akwai ƙaruwar Co-SAs/NPs@NC shine 0.13 eV, wanda ya ba da gudummawa cewa bayan gabatar da NP, shaƙar ƙwayoyin HCOO* ta hanyar tsarin lantarki da aka daidaita na CoN2C2 ya faru. Bambancin yawan caji yana nuna babban gajimare na lantarki a kusa da toshewar CoN2C2 da nanoparticle, yana nuna hulɗa mai ƙarfi tsakanin su saboda musayar lantarki. Idan aka haɗa shi da nazarin cajin Bader, an gano cewa Co da aka watsa ta atomatik ya rasa 1.064e a cikin Co-SA/NPs@NC da 0.796e a cikin Co SA (Hoto na S44). Waɗannan sakamakon sun nuna cewa haɗakar ƙwayoyin nanoparticles yana haifar da raguwar ƙwayoyin nano na wuraren Co, wanda ke haifar da ƙaruwar Covalence, wanda ya yi daidai da sakamakon XPS (Hoto na 6c). An yi nazarin halayen hulɗar Co-O na shaƙar HCOO a kan Co-SAs/NPs@NC da Co SA ta hanyar ƙididdige ƙungiyar Hamiltonian mai siffar crystalline (COHP)63. Kamar yadda aka nuna a Hoto na 6 d, ƙimar -COHP mara kyau da mai kyau sun yi daidai da yanayin hana haɗin kai da yanayin ɗaurewa, bi da bi. An kimanta ƙarfin haɗin Co-O wanda HCOO (Co-carbonylO HCOO*) ya shafa ta hanyar haɗa ƙimar -COHP, waɗanda suka kasance 3.51 da 3.38 ga Co-SAs/NPs@NC da Co-SA, bi da bi. Shaƙar HCOOH kuma ya nuna sakamako iri ɗaya: ƙaruwar ƙimar haɗin kai na -COHP bayan shan nanoparticle yana nuna ƙaruwar haɗin Co-O, ta haka yana haɓaka kunna HCOO da HCOOH (Hoto na S45).
Tsarin lattice na Co-SA/NPs@NC-950. b PDOS Co-SA/NP@NC-950 da Co SA. c 3D isosurface na bambancin yawan caji na HCOOH adsorption akan Co-SA/NPs@NC-950 da Co-SA. (d) pCOHP na Co-O bonds da HCOO ta shafa akan Co-SA/NPs@NC-950 (hagu) da Co-SA (dama). e Hanyar amsawar dehydrogenation na HCOOH akan Co-SA/NPs@NC-950 da Co-SA.
Domin fahimtar mafi kyawun aikin dehydrogenation na Co-SA/NPs@NC, an tantance hanyar amsawa da kuzari. Musamman, dehydrogenation na FA ya ƙunshi matakai biyar, gami da canza HCOOH zuwa HCOOH*, HCOOH* zuwa HCOO* + H*, HCOO* + H* zuwa 2H* + CO2*, 2H* + CO2* zuwa 2H* + CO2, da 2H* a cikin H2 (Hoto na 6e). Ƙarfin adsorption na ƙwayoyin formic acid akan saman catalyst ta hanyar carboxylic oxygen ya yi ƙasa da ta hanyar hydroxyl oxygen (Hoto na S46 da S47). Bayan haka, saboda ƙarancin kuzari, adsorbate ya fi dacewa ya shiga OH bond cling don samar da HCOO* maimakon CH bond cling don samar da COOH*. A lokaci guda, HCOO* yana amfani da monodentate adsorption, wanda ke haɓaka karya bonds da samuwar CO2 da H2. Waɗannan sakamakon sun yi daidai da kasancewar kololuwar νas (OCO) a cikin in situ DRIFT, wanda hakan ke nuna cewa lalacewar FA tana faruwa ta hanyar hanyar tsari a cikin bincikenmu. Yana da mahimmanci a lura cewa bisa ga ma'aunin KIE, rarrabuwar CH tana da shingen makamashin amsawa mafi girma fiye da sauran matakan amsawa kuma tana wakiltar RDS. Katangar makamashi na tsarin catalyst mafi kyau na Co-SAs/NPs@NC shine 0.86 eV ƙasa da na Co-SA (1.2 eV), wanda ke inganta ingancin dehydrogenation gabaɗaya. Abin lura shi ne, kasancewar nanoparticles yana daidaita tsarin lantarki na wuraren coactive da aka watsa ta atomic, wanda ke ƙara haɓaka shaye-shaye da kunna tsaka-tsaki, ta haka rage shingen amsawa da haɓaka samar da hydrogen.
A taƙaice, mun nuna a karon farko cewa ana iya inganta aikin catalytic na catalysts na samar da hydrogen sosai ta hanyar amfani da kayan da ke da cibiyoyin monometallic masu yaɗuwa da ƙananan ƙananan ƙwayoyin nano. An tabbatar da wannan ra'ayi ta hanyar haɗa ƙwayoyin cobalt guda ɗaya da aka gyara da ƙwayoyin nanoparticles (Co-SAs/NPs@NC), da kuma kayan da suka shafi cibiyoyin ƙarfe guda ɗaya kawai (CoN2C2) ko Co NPs. An shirya dukkan kayan ta hanyar hanyar pyrolysis mai sauƙi mai matakai ɗaya. Binciken tsari ya nuna cewa mafi kyawun catalyst (Co-SAs/NPs@NC-950) ya ƙunshi raka'o'in CoN2C2 da aka watsa ta atomic da ƙananan ƙwayoyin nanoparticles (7-8 nm) waɗanda aka cika da nitrogen da carbon mai kama da graphite. Yana da kyakkyawan yawan iskar gas har zuwa 1403.8 ml g-1 h-1 (H2:CO2 = 1.01:1), zaɓin H2 da CO na 99.96% kuma yana iya ci gaba da aiki akai-akai na kwanaki da yawa. Ayyukan wannan mai kara kuzari ya wuce ayyukan wasu masu kara kuzari na Co SA da Pd/C sau 4 da 15, bi da bi. Gwaje-gwajen DRIFT a cikin situ sun nuna cewa idan aka kwatanta da Co-SA, Co-SAs/NPs@NC-950 yana nuna ƙarfin shaƙar monodentate na HCOO*, wanda yake da mahimmanci ga hanyar tsari, kuma ƙwayoyin nanoparticles na dopant na iya haɓaka kunnawar HCOO* da haɓaka C-H. An gano raba haɗin a matsayin RDS. Lissafin ka'idoji sun nuna cewa shan Co NP yana ƙara cibiyar d-band na ƙwayoyin Co guda ɗaya da 0.13 eV ta hanyar hulɗa, yana haɓaka shaƙar HCOOH* da HCOO* matsakaici, ta haka yana rage shingen amsawa daga 1.20 eV don Co SA zuwa 0 .86 eV. Shi ne ke da alhakin kyakkyawan aiki.
Bugu da ƙari, wannan bincike yana ba da ra'ayoyi don ƙirƙirar sabbin abubuwan ƙarfafa ƙarfe na atom guda ɗaya da kuma haɓaka fahimtar yadda ake inganta aikin ƙarfafa ƙarfe ta hanyar tasirin haɗin gwiwa na cibiyoyin ƙarfe masu girma dabam-dabam. Mun yi imanin cewa wannan hanyar za a iya faɗaɗa ta cikin sauƙi ga sauran tsarin ƙarfafa ƙarfe da yawa.
An sayi Co(NO3)2 6H2O (AP, 99%), Zn(NO3)2 6H2O (AP, 99%), 2-methylimidazole (98%), methanol (99.5%), propylene carbonate (PC, 99%) ethanol (AR, 99.7%) daga McLean, China. An sayi Formic acid (HCOOH, 98%) daga Rhawn, China. An yi amfani da duk wani abu mai aiki kai tsaye ba tare da ƙarin tsarkakewa ba, kuma an shirya ruwan ultrapurep ta amfani da tsarin tsarkakewa na ultrapurep. An sayi Pt/C (5% na nauyin nauyi) da Pd/C (5% na nauyin nauyi) daga Sigma-Aldrich.
An gudanar da haɗakar nanocrystals na CoZn-ZIF bisa ga hanyoyin da suka gabata tare da wasu gyare-gyare23,64. Da farko, an haɗa 30 mmol Zn(NO3)2·6H2O (8.925 g) da 3.5 mmol Co(NO3)2·6H2O (1.014 g) kuma an narkar da su a cikin 300 ml na methanol. Sannan, an narkar da 120 mmol na 2-methylimidazole (9.853 g) a cikin 100 ml na methanol kuma an ƙara shi a cikin maganin da ke sama. An juya cakuda a zafin ɗaki na tsawon awanni 24. A ƙarshe, an raba samfurin ta hanyar centrifugation a 6429 g na minti 10 sannan aka wanke shi sosai da methanol sau uku. An busar da foda da aka samu a cikin injin tsabtace iska a 60°C dare ɗaya kafin amfani.
Domin haɗa Co-SAs/NPs@NC-950, an yi amfani da busasshen foda na CoZn-ZIF a zafin 950 °C na tsawon awa 1 a cikin kwararar iskar gas na 6% H2 + 94% Ar, tare da saurin dumama na 5 °C/min. Daga nan aka sanyaya samfurin zuwa zafin ɗaki don samun Co-SA/NPs@NC-950. Ga Co-SAs/NPs@NC-850 ko Co-SAs/NPs@NC-750, an canza zafin pyrolysis zuwa 850 da 750 °C, bi da bi. Ana iya amfani da samfuran da aka shirya ba tare da ƙarin sarrafawa ba, kamar etching acid.
An yi ma'aunin TEM (mai nuna hasken lantarki na watsawa) akan na'urar hangen nesa ta Thermo Fisher Titan Themis 60-300 "cube" wacce aka sanya mata mai gyara hoto da kuma ruwan tabarau mai siffar bincike na 300 kV. An gudanar da gwaje-gwajen HAADF-STEM ta amfani da na'urorin hangen nesa na FEI Titan G2 da FEI Titan Themis Z waɗanda aka sanye su da na'urori masu auna sigina da na'urori masu daidaita hoto, da kuma na'urorin gano sassa huɗu na DF4. An kuma sami hotunan taswirar abubuwan da ke cikin EDS akan na'urar hangen nesa ta FEI Titan Themis Z. An yi nazarin XPS akan na'urar hangen nesa ta X-ray photoelectron (samfurin Thermo Fisher ESCALAB 250Xi). An tattara XANES da EXAFS Co K-edge spectra ta amfani da teburin XAFS-500 (China Spectral Instruments Co., Ltd.). An tantance abubuwan da ke cikin Co ta hanyar amfani da na'urar hangen nesa ta atomic absorption spectroscopy (AAS) (PinAAcle900T). An yi rikodin spectra na X-ray diffractometer (XRD) akan na'urar auna hasken X-ray (Bruker, Bruker D8 Advance, Jamus). An samo isotherms na adsorption na nitrogen ta amfani da na'urar adsorption ta zahiri (Micromeritics, ASAP2020, Amurka).
An gudanar da aikin dehydrogenation a cikin yanayin argon tare da cire iska bisa ga hanyar Schlenk ta yau da kullun. An kwashe jirgin ruwan amsawar kuma an sake cika shi da argon sau 6. Kunna samar da ruwan condenser sannan a ƙara mai kara kuzari (30 mg) da mai narkewa (6 ml). Zafafa kwantenar zuwa zafin da ake so ta amfani da na'urar auna zafin jiki kuma a bar shi ya daidaita na minti 30. Daga nan aka ƙara Formic acid (10 mmol, 377 μL) zuwa jirgin amsawar da ke ƙarƙashin argon. Juya bawul ɗin burette mai hanyoyi uku don rage matsin lamba na reactor, rufe shi kuma, sannan a fara auna girman iskar gas da aka samar ta amfani da burette na hannu (Hoto na S16). Bayan lokacin da ake buƙata don kammala aikin, an tattara samfurin gas don nazarin GC ta amfani da sirinji mai hana iskar gas da aka tsarkake da argon.
An gudanar da gwaje-gwajen DRIFT a kan na'urar auna zafin jiki ta Fourier transform infrared (FTIR) spectrometer (Thermo Fisher Scientific, Nicolet iS50) wacce aka sanye da na'urar gano mercury cadmium telluride (MCT). An sanya foda mai auna zafin jiki a cikin ƙwayar amsawa (Harrick Scientific Products, Praying Mantis). Bayan an yi wa mai auna zafin jiki magani da rafin Ar (50 ml/min) a zafin ɗaki, an dumama samfurin zuwa yanayin zafin da aka bayar, sannan a zuba shi da kumfa da Ar (50 ml/min) a cikin maganin HCOOH sannan a zuba shi a cikin ƙwayar amsawar in-situ. don amsawa. Tsarin tsarin mai auna zafin jiki iri-iri. An yi rikodin spectra na infrared a tazara tsakanin daƙiƙa 3.0 zuwa awa 1.
Ana amfani da HCOOH, DCOOH, HCOOD da DCOOD a matsayin abubuwan da ke cikin propylene carbonate. Sauran yanayin sun dace da tsarin rage yawan sinadarin HCOOH.
An yi lissafin ƙa'idodi na farko ta amfani da tsarin ka'idar aiki mai yawa a cikin kunshin ƙirar Vienna Ab initio (VASP 5.4.4) 65,66. An yi amfani da tantanin halitta mai saman graphene (5 × 5) tare da girman juyawa na kimanin 12.5 Å a matsayin substrate don CoN2C2 da CoN2C2-Co6. An ƙara nisan injin fiye da 15 Å don guje wa hulɗa tsakanin layukan substrate da ke kusa. An bayyana hulɗar tsakanin ions da electrons ta hanyar hanyar haɓaka ƙarfin lantarki (PAW) da aka tsara65,67. An yi amfani da aikin Perdue-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) tare da gyaran van der Waals da Grimm68,69 ya gabatar. Ka'idojin haɗuwa don jimlar kuzari da ƙarfi sune 10−6 eV/atom da 0.01 eV/Å. An saita yankewar makamashi a 600 eV ta amfani da grid na maki na Monkhorst-Pack 2 × 2 × 1 K. An gina ƙarfin da aka yi amfani da shi a cikin wannan samfurin daga tsarin lantarki zuwa yanayin C 2s22p2, yanayin N 2s22p3, yanayin Co 3d74s2, yanayin H 1 s1, da yanayin O 2s22p4. Ana ƙididdige kuzarin sha da bambancin yawan electron ta hanyar cire kuzarin yanayin iskar gas da nau'in saman daga kuzarin tsarin shaye-shaye bisa ga samfuran shaye-shaye ko hanyoyin sadarwa70,71,72,73,74. Ana amfani da gyaran makamashin Gibbs kyauta don canza makamashin DFT zuwa makamashin Gibbs kyauta kuma yana la'akari da gudummawar girgiza zuwa entropy da makamashin sifili mai maki 75. An yi amfani da hanyar hawa hoto mai nudging elastic band (CI-NEB) don neman yanayin sauyawa na amsawar76.
Duk bayanan da aka samu kuma aka yi nazari a kansu a lokacin wannan binciken an haɗa su a cikin labarin da ƙarin kayan aiki ko kuma ana samun su daga marubucin da ya dace bisa buƙata mai ma'ana. An samar da bayanan tushe don wannan labarin.
Duk lambar da aka yi amfani da ita a cikin kwaikwayon da ke tare da wannan labarin tana samuwa daga marubutan da suka dace idan an buƙata.
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