Waad ku mahadsan tahay booqashada Nature.com.Waxaad isticmaalaysa nooc browser ah oo leh taageero CSS xaddidan.Waayo-aragnimada ugu fiican, waxaan kugula talineynaa inaad isticmaasho browser-ka la cusboonaysiiyay (ama aad damiso Habka Laqabsiga ee Internet Explorer).Intaa waxaa dheer, si loo hubiyo taageerada joogtada ah, waxaan ku tusineynaa goobta aan lahayn qaabab iyo JavaScript.
Waxa uu soo bandhigayaa carousel ka kooban saddex slide hal mar.Isticmaal badhamada hore iyo kan ku xiga si aad ugu gudubto saddex sawir markiiba, ama isticmaal badhamada slider-ka ee dhamaadka si aad ugu gudubto saddex sawir markiiba.
Naqshadeynta iyo horumarinta waxqabadyada firfircoonida sare waxay heleen fiiro gaar ah xagga falcelinta hydrogenation-ka ee xulashada ah laakiin weli waa caqabad weyn.Halkan waxaan ku soo gudbineynaa mootomic RuNi alloy (SAA) kaas oo atomyada ru-ga gaarka ah ay ku dhaqaaqi karaan dusha sare ee Ni nanoparticles iyada oo loo sii marayo isuduwidda Ru-Ni, kaas oo ay la socoto wareejin elektaroonig ah oo ka imanaya dhulka hoose ee Ni ilaa Ru.Aqoontayada, kicinta ugu fiican 0.4% RuNi SAA isku mar waxay muujisay waxqabad sare (qiimaha TOF: 4293 h-1) iyo chemoselectivity ee hydrogenation-ka xulashada ee 4-nitrostyrene ilaa 4-aminostyrene (wax soo saar:> 99%), heerka ugu sarreeya by marka la barbar dhigo kiciyeyaasha kala duwan ee la yaqaan.Tijaabooyinka goobta iyo xisaabinta aragtida waxay muujinayaan in Ru-Ni interfaces, sida goobaha firfircoon ee gudaha, ay kor u qaadaan jebinta doorbidida ee NO bonds oo leh caqabad hoose oo tamar ah 0.28 eV.Intaa waxaa dheer, ru-Ni catalysis synergistic waxay door bidaa samaynta dhexdhexaadiyeyaasha (C8H7NO* iyo C8H7NOH*) waxayna kordhisaa heerka go'aaminta heerka (hydrogenation of C8H7NOH*).
Amines caraf udgoon functionalized, blocks dhismaha muhiimka ah ee kiimikooyinka ganaax, leeyihiin codsiyada warshadaha muhiim ah in wax soo saarka ee dawooyinka, agrochemicals, pigments iyo polymers1,2,3.Haydaroojin-ka-soo-baxa ee xeryahooda nitroaromatic ee diyaarka ah ee la heli karo oo ka sarreeya kiciyayaal kala duwan ayaa soo jiitay fiiro gaar ah sida hab deegaan saaxiibtinimo leh oo dib loo warshadayn karo oo loogu talagalay isku dhafka amines oo leh qiime lagu daray4,5,6,7.Si kastaba ha ahaatee, hoos u dhigista kiimikaad ee kooxaha -NO2 iyada oo la sii hayo kooxaha kale ee la dhimi karo sida alkenes, alkynes, halogens, ama ketones waa hawl aad loo jecel yahay laakiin waa hawl adag8,9,10,11.Sidaa darteed, isticmaalka macquulka ah ee kicinta kala duwan ee dhimista gaarka ah ee kooxaha -NO2 iyada oo aan saameyn ku yeelan curaarta kale ee la dhimi karo ayaa aad loo jecel yahay12,13,14.Waxyaalo badan oo bir-la'aan ah ayaa la baadhay si ay u kiciyaan hydrogenation of nitroarenes, laakiin xaaladaha falcelinta qallafsan ayaa ka hortagaya codsigooda ballaaran15,16.In kasta oo biraha sharafta leh (sida Ru17, Pt18, 19, 20 ama Pd21, 22, 23) ay ku firfircoon yihiin xaaladaha falcelinta khafiifka ah, waxay caadi ahaan la ildaran yihiin qiime sare, xulashada hoose, iyo isticmaalka atamka hooseeya.Sidaa darteed, helida kimikal firfircoon oo firfircoon iyo kimoysdooriye iyadoo la adeegsanayo naqshad maangal ah iyo habayn wanaagsan oo qaab dhismeedka wanaagsan ayaa ah caqabad weyn24,25,26.
Dabeecadaha Monatomic Alloy (SAA) waxay leeyihiin waxtarka ugu sarreeya ee birta sharafta leh, qaab-dhismeedka joomatari ee gaarka ah iyo qaab-dhismeedka elektarooniga ah, waxay bixiyaan goobo firfircoon oo gaar ah, waxayna bixiyaan waxqabadka firfircoonida leh iyagoo jebiya dabeecadda cabbirka toosan ee sifaha27,28,29,30,31.Atamyada hal-doorka ah ee la sameeyay iyo atomyada biraha ah ee martida loo yahay ee SAA waxay u adeegi karaan sidii laba goobood oo firfircoon, fududaynta firfircoonida substrate-ka badan ama u oggolaanaya talaabooyinka falcelinta aasaasiga ah ee kala duwan inay ka dhacaan goobo kala duwan32,33,34.Intaa waxaa dheer, ururada heterometallic ee u dhexeeya atomyada birta ee wasakhaysan ee go'doonsan iyo biraha martida loo yahay waxay u horseedi karaan saameyn is-dhexgal ah, in kasta oo fahamka saamaynta isku-dhafka ah ee u dhexeeya laba qaybood oo ah goobaha birta ee heerka atomikada ayaa weli ah muran35,36,37,38.Haydaroojin ee nitroarenes functionalized, qaab-dhismeedka elektarooniga ah iyo joomatari ee goobaha firfircoon waa in loo qaabeeyey si ay u dardar firfircoon ee kooxaha nitro gaar ah.Sida caadiga ah, kooxaha nitro-ga yar ee elektarooniga ah ayaa inta badan lagu dhajiyaa gobollada nucleophilic ee dusha sare ee kicinta, halka dariiqa hydrogenation-ka ee xiga, catalysis iskaashi ee goobaha firfircoon ee deriska ah ayaa door muhiim ah ka ciyaari doona xakamaynta falcelinta iyo chemoselectivity4,25.Tani waxay nagu kalliftay inaan sahamno kicinta SAA oo ah musharrax rajo leh oo lagu hagaajinayo waxtarka kicinta ee hydrogenation chemoselective ee xeryahooda nitroaromatic, iyo sidoo kale sii kordhinta xiriirka ka dhexeeya qaab dhismeedka goobta firfircoon iyo waxqabadka cabirka atomiga.
Halkan, kiciyayaal ku salaysan monatomic RuNi alloys ayaa la diyaariyey iyadoo lagu salaynayo hab laba-heer ah oo synthetic ah, oo ay ku jiraan beddelka qaab-dhismeedka-topological ee lakabka laba-jibbaaran ee hydroxide (LDH) oo ay ku xigto daaweynta koronto-barakaca.RuNi SAA waxay soo bandhigaysaa waxtarka catalytic-ga gaarka ah (> 99% dhalidda) ee hydrogenation chemoselective ee 4-nitrostyrene ilaa 4-aminostyrene oo leh soo noqnoqoshada soo noqnoqda (TOF) ilaa ~ 4300 mol-mol Ru-1 h-1, taas oo ah tan ugu sareysa. heerka ka mid ah kicinta kala duwan ee ka diiwaan gashan xaaladaha falcelin la mid ah.Mikroskoobyada korantada iyo sifada spectroscopic waxay muujisay in atomyada ru-go'an ay ku kala firirsan yihiin dusha sare ee Ni nanoparticles (~ 8 nm), samaynta isuduwidda Ru-Ni xasilloon, taasoo keentay in goobaha Ruδ-) ay sabab u tahay wareejinta elektarooniga ah ee Ni nanoparticles .In goobta FT-IR, daraasaadka XAFS iyo xisaabinta cufnaanta functional aragti (DFT) ayaa xaqiijiyay in goobaha Ru-Ni interface sida goobaha firfircoon ee gudaha fududeeyo nitro.Xayeysiis firfircooni leh (0.46 eV) way ka duwan tahay kan nikkelka monometallic.(0.74 eV).Intaa waxaa dheer, kala qaybsanaanta hydrogen waxay ku dhacdaa jagooyinka Ni ee deriska ah, oo ay ku xigto hydrogenation of intermediates (C8H7NO* iyo C8H7NOH*) ee boosaska Ruδ.Saamaynta isku-dhafka ah ee taageerada doping-ka ee RuNi SAA kicinta waxay keentaa firfircoonida hydrogenation nitroarenes iyo xulashada, taas oo lagu kordhin karo biraha kale ee qaaliga ah ee naadirka ah ee loo isticmaalo qaabdhismeedka falcelinta xasaasiga ah.
Iyada oo ku saleysan kala-guurka qaab dhismeedka qaab-dhismeedyada hore ee lakabka ah ee double hydroxide (LDH), waxaanu diyaarinay monometallic Ni oo lagu shubay substrates Al2O3 amorphous ah.Taas ka dib, qayb ka mid ah ruNi/Al2O3 bimetallic muunado leh noocyo kala duwan oo Ru (0.1-2 wt %) ayaa si sax ah loo farsameeyey by electrodisplacement si ay u dhigaan atomyada Ru on dusha Ni nanoparticles (NPs) (Jaantus. 1a).Cabbiraadaha qiiqa hawada ka sii daaya balaasmaha oo si firfircoon ugu lammaansan (ICP-AES) waxay si cad u siiyeen halabuurka aasaasiga ah ee Ru iyo Ni ee muunadahan (Jadwalka Dheeraadka ah 1), kaas oo u dhow rarida kaydka quudinta.Sawirada SEM (Jaantuska Dheeraadka ah 1) iyo natiijooyinka BET (Jaantusyada Dheeraadka ah 2-9 iyo Jadwalka Dheeraadka 1) waxay si cad u muujinayaan in qaab-dhismeedka morphological iyo aagga gaarka ah ee shaybaarada RuNi / Al2O3 aysan ku dhicin isbeddel muuqda inta lagu jiro daaweynta korantada.- habka socodka.Habka raajada (Jaantus. 1b) waxay muujinaysaa taxane muuqaal ah oo muuqaal ah 2θ 44.3 °, 51.6 °, iyo 76.1 °, oo tilmaamaya wejiyada (111), (200), iyo (220) ee caadiga ah Ni (JCPDS 004-0850). ).Waxaa xusid mudan, shaybaarada RuNi ma muujiyaan milicsiga Ru- bir ah ama oksaydhaysan, taas oo muujinaysa kala firidhsanaan sare oo noocyada Ru ah.Mikroskoobyada elektarooniga ah ee gudbinta (TEM) ee shaybaarada monometallic Ni iyo RuNi (Jaantus. 1c1-c8) waxay muujinayaan in nanoparticles nikkel ay si fiican u kala firdhiyeen oo ay u dhaqaaqeen taageerada Al2O3 oo aan caadi ahayn oo leh cabbir isku mid ah (7.7-8.3 nm).Sawirada HRTEM (Sawirrada 1d1-d8) waxay muujinayaan xilli isku mid ah oo ku saabsan 0.203 nm ee shaybaarrada Ni iyo RuNi, oo u dhiganta Ni(111) dayuuradaha, si kastaba ha ahaatee, cidhifyada shafka ah ee qaybaha Ru ayaa maqan.Tani waxay tusinaysaa in atamyada ruku ay aad ugu kala firdhisan yihiin sambabada sambabada oo aanay saamayn ku yeelanayn wakhtiga Ni.Dhanka kale, 2 wt% Ru/Al2O3 waxaa lagu farsameeyay habka dhigaalka-dhigista sida kantaroolka, kaas oo rucubyada Ru ay si isku mid ah ugu qaybiyeen dusha sare ee Al2O3 substrate (Sawirro Dheeraad ah 10-12).
Qorshaha dariiqa isku xidhka ee muunadaha RuNi/Al2O3, qaababka kala duwanaanshiyaha raajada ee Ni/Al2O3 iyo muunado kala duwan oo RuNi/Al2O3 ah.c1-c8 TEM iyo d1-d8 HRTEM sawirada grating oo leh kala qaybinta cabbirka walxaha ee monometallic Ni, 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0, 8% wt., 1 wt.Sawir la jeexay.% iyo 2 wt.% RuNi."au" macneheedu waa unugyo aan sabab lahayn.
Dhaqdhaqaaqa catalytic ee shaybaarada RuNi waxaa lagu daraaseeyay kiimikaad hydrogenation-ka 4-nitrostyrene (4-NS) ilaa 4-aminostyrene (4-AS).Beddelka 4-NS ee substrate saafiga ah ee Al2O3 wuxuu ahaa kaliya 0.6% 3 saacadood kadib (Shaxda Dheeraadka ah 2), taasoo muujinaysa saamayn yar oo katalytik ah oo Al2O3 ah.Sida ku cad fig.2a, kicinta nikkel ee asalka ah waxay soo bandhigtay firfircooni firfircooni aad u hooseeya oo leh 4-NS beddelaad 7.1% 3 saacadood ka dib, halka 100% beddelka lagu gaari karo joogitaanka monometallic Ru kicinta isla shuruudo isku mid ah.Dhammaan kiciyayaasha RuNi waxay muujiyeen firfircoonida hydrogenation-ka oo si weyn u kordhay (isbeddelka: ~ 100%, 3 h) marka la barbar dhigo shaybaarrada monometallic, iyo heerka falcelinta ayaa si togan ula xidhiidha nuxurka Ru.Tani waxay ka dhigan tahay in qaybaha Ru ay door muhiim ah ka ciyaaraan habka hydrogenation-ka.Waxa xiisaha lihi leh, xulashada badeecada (Jaantus. 2b) aad ayey u kala duwan tahay iyadoo ku xidhan kiciye.Dhaqdhaqaaqa yar ee nikkel saafiga ah, wax soo saarka ugu muhiimsan wuxuu ahaa 4-nitroethylbenzene (4-NE) (doorashada: 83.6%) iyo xulashada 4-AC waxay ahayd 11.3%.Xaaladda monometallic Ru, curaarta C = C ee 4-NS waxay aad ugu nugul tahay hydrogenation marka loo eego -NO2, taasoo keenta samaynta 4-nitroethylbenzene (4-NE) ama 4-aminoethylbenzene (4-AE);Xulashada 4-AC waxay ahayd kaliya 15.7%.Waxaa la yaab leh, kiciyayaasha RuNi oo leh wax yar oo Runi ah (0.1-0.4 wt%) waxay muujiyeen xulasho aad u wanaagsan (> 99%) ilaa 4-aminostyrene (4-AS), taasoo muujinaysa inay tahay NO2 oo aanay ahayn vinyl, waa kiimiko la soo xulay oo gaar ah.Marka nuxurka Ru uu dhaafo 0.6 wt.%, xulashada 4-AS ayaa si aad ah hoos ugu dhacday iyadoo la kordhinayo loading Ru, halka xulashada 4-AE uu kordhay.Xakamaynta ka kooban 2 wt% RuNi, labada nitro iyo kooxaha vinyl labaduba waxay ahaayeen kuwo hydrogenated ah oo leh xulashada sare ee 4-AE ee 98%.Si loo daraaseeyo saamaynta ay ku leedahay gobolka ru-faafinta ee falcelinta catalytic, 0.4 wt% Ru/Al2O3 muunado ayaa la diyaariyey (Tirooyinka dheeriga ah 10, 13 iyo 14) kuwaas oo qaybaha Ru inta badan loo kala firdhiyey sida atamka shaqsiga ah oo ay ku xigto dhawr rucubyo Ru.(quasi-atomic Ru).Waxqabadka catalytic (Shaxda Dheeraadka ah 2) waxay muujineysaa in 0.4 wt% Ru/Al2O3 ay wanaajiso xulashada 4-AS (67.5%) marka la barbar dhigo muunada 2 wt% Ru/Al2O3, laakiin hawshu aad bay u hooseysaa (isbeddelka: 12.9).%;3 saacadood).Iyada oo ku saleysan tirada guud ee goobaha birta ah ee dusha sare ee lagu go'aamiyay CO pulsed cabbirada chemisorption, inta jeer ee wareegitaanka (TOFmetal) ee kicinta RuNi waxaa lagu helay beddelka 4-NS hooseeya (Jaantuska Dheeraadka ah. 15), kaas oo muujiyay isbeddel marka hore si loo kordhiyo ka dibna la dhimo korodhka korodhka Ru- raynta (Jaantuska Dheeraadka ah 16).Tani waxay soo jeedinaysaa in dhammaan goobaha birta ee dusha sare aysan u dhaqmin sidii goobo firfircoon oo loogu talagalay kicinta RuNi.Intaa waxaa dheer, TOF ee kicinta RuNi waxaa laga soo xisaabiyay RuNi sites si loo sii muujiyo waxqabadkeeda catalytic gudaha (Jaantus. 2c).Marka waxa ku jira Ru uu kordho 0.1 wt.% ilaa 0.4 wt.% Kaaliyeyaasha RuNi waxay muujiyeen ku dhawaad ​​​​qiyamka TOF ee joogtada ah (4271-4293 h-1), taas oo muujinaysa meelaynta qaybaha Ru ee kala firdhisanaanta atomiga (laga yaabo in la sameeyo RuNi SAA).) waxayna u adeegtaa sida goobta ugu muhiimsan ee firfircoon.Si kastaba ha ahaatee, korodhka dheeraadka ah ee rarida Ru (gudahood 0.6-2 wt%), qiimaha TOF ayaa si weyn hoos ugu dhacaya, taas oo muujinaysa isbeddelka qaabdhismeedka gudaha ee xarunta firfircoon (laga bilaabo kala firdhinta atomiga ilaa Ru nanoclusters).Intaa waxaa dheer, ogaanshahayaga, TOF ee 0.4 wt% RuNi (SAA) kicinta ayaa ku jirta heerka ugu sarreeya ee biraha birta ah ee hore loogu soo sheegay xaaladaha falcelinta ee la midka ah (Shaxda Dheeriga ah 3), taas oo muujinaysa in monoatomic RuNi alloys ay bixiyaan sifooyin tayo sare leh.daawasho.Jaantuska dheeriga ah ee 17 waxa uu muujinayaa waxqabadka catalytic ee 0.4 wt% RuNi (SAA) kicinta cadaadiska iyo heerkulka kala duwan ee H2, halkaas oo cadaadiska H2 ee 1 MPa iyo heerkulka falcelinta ee 60 °C loo isticmaalay cabbirrada falcelinta ugu fiican.muunad ka kooban RuNi 0.4 wt.% (Jaantus. 2d), mana jirin hoos u dhac weyn oo ku yimid dhaqdhaqaaqa iyo wax-soo-saarka ayaa la arkay in ka badan shan wareeg oo isku xigta.Sawirada raajada iyo TEM ee 0.4 wt% RuNi kicinta loo isticmaalo ka dib wareegyada 5 (Tirooyinka Dheeraadka ah 18 iyo 19) ma muujin isbeddel weyn oo ku yimid qaab-dhismeedka crystal, taas oo muujinaysa xasilloonida sare ee falcelinta hydrogenation-ka.Intaa waxaa dheer, kicinta 0.4 wt% RuNi (SAA) waxay sidoo kale bixisaa wax soo saar aad u fiican oo amines ah oo loogu talagalay hydrogenation chemoselective ee xeryahooda kale ee nitroaromatic oo ay ku jiraan halogens, aldehydes, iyo kooxaha hydroxyl (Shaxda Dheeraadka ah 4), oo muujinaysa ku-dhaqankeeda wanaagsan.
Beddelka Catalytic iyo b qaybinta 4-nitrostyrene hydrogenation Products iyadoo ay joogaan monometallic Ni, Ru, iyo RuNi kiciyayaal ka kooban Runi kala duwan (0.1-2 wt%), c ee kala duwanaanshaha firfircoonida firfircoonida, Soo noqnoqoshada (TOF) ee RuNi kicinta c ku xiran tahay Ru per mole.d Tijaabi suurtagalnimada dib-u-isticmaalka 0.4 wt.% RuNi kicinta shan wareeg oo isku xigta.ln (C0 / C) waxay ku saleysan tahay waqtiga falcelinta hydrogenation-ka e-nitrobenzene iyo f-styrene oo leh isku dar ah nitrobenzene iyo styrene (1: 1).Xaaladaha falcelinta: 1 mmol reagent, 8 ml dareere (ethanol), kicinta 0.02 g, 1 MPa H2, 60°C, 3 saacadood.Baararka qaladka waxaa lagu qeexaa inay yihiin weecista caadiga ah ee saddex nuqul.
Si loo sii baaro farqiga muhiimka ah ee kiimikaad-dooriyaha, hydrogenation-ka isku dhafka styrene iyo nitrobenzene (1:1) ayaa sidoo kale lagu fuliyay joogitaanka hal-abuurka monometallic Ni, Ru, 0.4 wt% RuNi, iyo 2 wt% RuNi, siday u kala horreeyaan (Sawir Dheeraad ah) 20).Inkasta oo chemoselectivity ee falcelinta hydrogenation ee kooxaha functional waa joogto ah, runtii waxaa jira qaar ka mid ah kala duwanaansho ee xulashada ee hydrogenation intramolecular iyo intermolecular ay sabab u tahay saamaynta allosteric kelli.Sida ku cad fig.2e,f, qalooca ln (C0/C) iyo wakhtiga falcelinta waxay siinaysaa xariiq toosan oo asal ah, taas oo muujinaysa in nitrobenzene iyo styrene labaduba ay yihiin falcelin nidaameed been abuur ah.Xakamaynta nikkel-ka monoometallic waxay muujisay joogteynta heerka hydrogenation aad u hooseeya ee p-nitrobenzene (0.03 h-1) iyo styrene (0.05 h-1).Waxaa xusid mudan, dhaqdhaqaaqa hydrogenation styrene ee la doorbidi karo (heerka joogtada ah: 0.89 h-1) ayaa lagu gaadhay kicinta Ru monometallic, taas oo aad uga sareysa dhaqdhaqaaqa hydrogenation nitrobenzene (heerka joogtada ah: 0.18 h-1).Xaaladda kicinta ka kooban RuNi(SAA) 0.4 wt.% hydrogenation nitrobenzene ayaa si firfircoon uga faa'iido badan hydrogenation styrene (heerka joogtada ah: 1.90 h-1 vs. 0.04 h-1), taasoo muujinaysa doorbidida kooxda -NO2.in ka badan C hydrogenation = bond C. Wixii kicinaya 2 wt.% RuNi, heerka joogtada ah ee hydrogenation nitrobenzene (1.65 h-1) ayaa hoos u dhacay marka loo eego 0.4 wt.% RuNi (laakiin wali wuu ka sarreeyaa kii birta mono-metal), halka heerka hydrogenation-ka ee styrene uu si aad ah u kordhay (heerka joogtada ah: 0.68).h-1).Tani waxay sidoo kale muujinaysaa in saamaynta is-dhexgalka ee udhaxeysa Ni iyo Ru, firfircoonida firfircoonida iyo kiimikaad ee kooxaha -NO2 ay si weyn u korodhay marka loo eego RuNi SAA.
Si muuqaal ahaan loo go'aamiyo xaaladaha kala firdhisan ee Ru iyo Ni xeryahooda, hab sawir iyadoo la adeegsanayo giraanta xagal-sare ee sawirka mugdiga ah ee microscopy elektarooniga ah oo leh hagaajinta aberration (AC-HAADF-STEM) iyo khariidad curiye by tamarta kala firdhiso spectroscopy (EDS) ayaa la sameeyay.Khariidadda aasaasiga ah ee EMF ee muunadda oo leh 0.4 wt% RuNi (Jaantus. 3a, b) waxay muujinaysaa in Ru uu si heersare ah ugu kala firdhiyey nanoparticles nikkel, laakiin aan ku jirin substrate-ka Al2O3, sawirka AC-HAADF-STEM ee u dhigma (Berdihii. 3c) waxay muujinaysaa, Waxaa la arki karaa in dusha sare ee Ni NPs ay ku jiraan dhibco badan oo dhalaalaya oo cabbirka atomiga ah ee atomyada Ru (oo lagu calaamadeeyay fallaadho buluug ah), halka aan rucubyada ama ru nanoparticles midna la arkin.Jaantuska 3d), oo muujinaya samaynta alwaaxyada monatomic RuNi.Muunad ka kooban RuNi 0.6 wt.% (Jaantus. 3e), hal atomyada Ru iyo qadar yar oo ka mid ah qaybaha ru-ga ah ayaa lagu arkay Ni NPs, taas oo muujinaysa isku darka yar ee atamka Ru sababtoo ah culeyska kordhay.Marka laga hadlayo muunad ka kooban 2 wt% RuNi, rucubyo badan oo waaweyn oo Ni NPs ah ayaa laga helay sawirka HAADF-STEM (Jaantus. 3f) iyo EDS khariidaynta aasaasiga ah (Jaantuska Dheeraadka ah. 21), taasoo muujinaysa ururin ballaaran oo Ru .
sawirka HAADF-STEM, b u dhigma sawirka khariidaynta EDS, c xal sare AC-HAADF-STEM image, d sawirka STEM la wayneeyey iyo qaybinta xoojinta u dhiganta 0.4 wt% muunada RuNi.(e, f) AC-HAADF-STEM sawirada muunado ka kooban 0.6 wt.% RuNi iyo 2 wt.% RuNi, siday u kala horreeyaan.
Marka la barbardhigo Ni/Al2O3 iyo Ru/Al2O3 muunadaha, DRIFTS spectra CO adsorption in situ ayaa la sameeyay (Jaantus. 4a) si loo sii daraaseeyo tafaasiisha qaabdhismeedka muunado ka kooban 0.4 wt.%, 0.6 wt.% iyo 2 wt.% RuNi.Xayeysinta CO ee muunada Ru/Al2O3 waxa ay siinaysaa ugu sarraysa 2060 cm-1 iyo mid kale oo ballaadhan oo ah 1849 cm-1 oo loo aanaynayo xayaysiisyada CO ee tooska ah ee Ru iyo isku xidhka labada atamka ee deriska ah, siday u kala horreeyaan CO39,40.Muunadda monometallic Ni, ugu sarreysa ayaa lagu arkay kaliya 2057 cm-1, taas oo loo aaneynayo CO41,42 toosan oo ku taal gobolka nikkel.Muunadda RuNi, marka lagu daro meesha ugu sarreysa ee 2056 cm-1, waxaa jira garab gooni ah oo udub dhexaad u ah ~ 2030 cm-1.Habka ugu habboon ee ugu sarreeya ee Gaussian ayaa loo adeegsaday si macquul ah u kala qaybinta qaybinta shaybaarada RuNi ee 2000-2100 cm-1 iyo qaybinta CO ee gobolka Ni (2056 cm-1) iyo gobolka Ru (2031-2039 cm).Laba sare ayaa si toos ah loogu dhajiyay - 1) (Jaantus. 4b).Waxa xiisaha lihi leh, laga bilaabo shaybaarrada Ru/Al2O3 (2060 cm–1) ilaa muunadaha RuNi (2031-2039 cm–1), CO ee ugu sarreysa CO ee gobolka Ru waxa ay maraysaa isbeddel weyn oo casaan ah waxayna kordhisaa korodhka nuxurka Ru.Tani waxay muujinaysaa kororka korantada ee qaybaha Ru ee muunada RuNi, taas oo ah natiijada wareejinta elektarooniga ah ee Ni to Ru, kordhinta jawaab celinta d-π elektarooniga ee Ru una socota CO 2π* orbital-ka-hortagga.Intaa waxaa dheer, muunad ka kooban 0.4 mass% RuNi, lama arkin heerka ugu sarreeya ee xayaysiinta, taas oo muujinaysa in qaybaha Ru ay u jiraan sida Ni atoamka goonida ah (SAA).Xaaladda muunado leh 0.6 wt.% RuNi iyo 2 wt.% RuNi, joogitaanka isku xidhka CO waxay xaqiijinaysaa jiritaanka ru multimers ama rucubyada, kaas oo si fiican ula heshiiyey natiijooyinka AC-HAADF-STEM.
a In goobta CO-DRIFTS spectra Ni/Al2O3, Ru/Al2O3 iyo 0.4 wt.%, 0.6 wt.%, 2 wt.% RuNi muunado leh socodka gaasta helium ee kala duwan 2100-1500 cm-1 20 min.b Miisaaman iyo Gaussian-ku-habboon ee muunada RuNi/Al2O3 oo leh boosas sare oo go'an iyo FWHM.c In goobta Ru K- gees XANES spectra iyo d EXAFS Fourier waxay beddelaan spectra muunado kala duwan.Beddelka wavelet-ka K2 ee calaamadaha XAFS K-edge Ru ee ku salaysan mowjadaha Morlet ee e Ru muunadaha e Ru foil, f 0.4 wt% RuNi iyo g RuO2."au" macneheedu waa unugyo aan sabab lahayn.
Caadi ahaan goobta qaab dhismeedka nuugista raajada qaab dhismeedka nuugista raajada (XANES) ayaa la sameeyay si loo darso qaab dhismeedka elektiroonigga ah iyo qaab dhismeedka joomatari ee muunadaha RuNi oo wata muunado Ru foil iyo ruO2.Sida ku cad fig.4c, marka rarka ruku hoos u dhaco, xoojinta xariiqda cad waxay si tartiib tartiib ah hoos ugu dhacdaa shaybaarada Ru/Al2O3 ilaa muunadaha RuNi.Dhanka kale, xoojinta xariiqda cad ee xariiqda XANES ee K-cirifka Ni waxay muujinaysaa koror yar marka loo eego muunadda asalka ah ee Ni ilaa muunadda RuNi (Jaantuska Dheeraadka ah 22).Tani waxay muujinaysaa isbeddelka cufnaanta elektarooniga ah iyo isku-dubbaridka deegaanka ee xeryahooda Ru.Sida ku cad sawirka X-ray photoelectron spectroscopy (XPS) spectra (Jaantuska Dheeraadka ah 23), meesha ugu sarraysa ee RuNi ee muunada RuNi waxa ay u wareegtay tamar xidhid hoose iyo Ni0 ugu sarraysa waxa ay u wareegtay tamar xidhid sare ah marka loo eego monometallic Ru iyo Ni., kaas oo sidoo kale muujinaya wareejinta elektarooniga ah ee Ni atamka ilaa ru atamka ee RuNi SAA.Falanqaynta kharashka Bader ee RuNi SAA(111) oogada waxay tusinaysaa in atamka ru-go'doonku xanbaarsan yahay eedaymo taban (Ruδ-) laga soo wareejiyay nimiyada hoose ee Ni (Jaantuska Dheeraadka ahSi aan u barano qaab dhismeedka faahfaahsan ee isuduwidda Ru (Jaantus. 4d), waxaanu samaynay nuugista raajada fidsan ee fican-grained spectroscopy (EXAFS) ee isbedelka Fourier.Tusaalaha ka kooban RuNi 0.4 wt.% waxay leedahay meel sare oo af leh ~ 2.1 Å, oo ku taal gobolka u dhexeeya Ru-O (1.5 Å) iyo Ru-Ru (2.4 Å), kaas oo loo aanayn karo isku-dubbaridka Ru-Ni44, 45. Natiijooyinka ku habboon xogta EXAFS (Shaxda 5 ee Dheeraadka ah iyo Jaantusyada Dheeraadka ah 25-28) waxay muujinayaan in dariiqa Ru-Ni uu leeyahay nambar isku-dubarid (CN) oo ah 5.4, halka aysan jirin isuduwidda Ru-Ru iyo Ru-O ee 0.4 wt.% Muunada RuNiTani waxay xaqiijinaysaa in atamka ugu muhiimsan ee Ru ay si atomi ahaan u kala firdhisan yihiin oo ay ku hareeraysan yihiin Ni, samaynta daawaynta monoatomic.Waa in la ogaadaa in xoojinta ugu sarreysa (~ 2.4 Å) ee isuduwidda Ru-Ru ay ka muuqato muunad ah 0.6 wt.% RuNi waxaana lagu xoojiyay muunada 2 wt.% RuNi.Gaar ahaan, ku habboonaanta qalooca EXAFS waxay muujisay in tirooyinka isuduwidda Ru-Ru ay si aad ah uga kordheen 0 (0.4 wt.% RuNi) ilaa 2.2 (0.6 wt.% RuNi) oo ay sii korodhay ilaa 6.7 (2 wt.% .% RuNi), siday u kala horreeyaan. , taasoo muujineysa in marka culeyska Ru uu kordho, atomyada Ru ay si tartiib tartiib ah isu geeyaan.Beddelka mawjada K2-miisaanka leh (WT) ee calaamadaha Ru K-cirifka XAFS ayaa sidoo kale loo isticmaalay in lagu barto jawiga isuduwidda ee noocyada Ru.Sida ku cad fig.4e, Ru foil lobes 2.3 Å, 9.7 Å-1 tixraac tabaruca Ru-Ru.Muunad ka kooban RuNi 0.4 wt.% (Jaantus. 4f) ma jiraan lobes at k = 9.7 Å-1 iyo 5.3 Å-1, marka laga reebo curaarta dhexe ee Ru iyo atomyada O (Jaantus. 4g);Ru-Ni waxaa lagu arkay 2.1 Å, 7.1 Å-1, taasoo caddaynaysa samaynta SAA.Intaa waxaa dheer, spectra EXAFS ee K-cirifka Ni ee muunado kala duwan ma muujin wax farqi weyn ah (Jaantuska Dheeraadka ah. 29), taas oo muujinaysa in qaab dhismeedka isuduwidda Ni uu saameyn yar ku leeyahay atomyada Rugaha.Marka la soo koobo, natiijooyinka AC-HAADF-STEM, goobta CO-DRIFTS, iyo goobta tijaabooyinka XAFS waxay xaqiijiyeen diyaarinta guusha leh ee kicinta RuNi SAA iyo kobcinta qaybaha Ru ee Ni NPs ee hal atom ilaa ru multimers iyadoo la kordhinayo Ru rar.Intaa waxaa dheer, sawirada HAADF-STEM (Jaantuska Dheeraadka ah. 30) iyo EXAFS spectra (Jaantuska Dheeraadka ah. 31) ee RuNi SAA kicinta ee la isticmaalay waxay muujiyeen in gobolka kala firidhsan iyo qaab dhismeedka isuduwidda ee atomyada Ru aysan si weyn isbeddelin ka dib wareegyada 5, taas oo caddaynaysa. in ruNi SAA xasiloon .
Qiyaasta H2-TPD ayaa la sameeyay si loo barto xayeysiiska kala-baxa ee hydrogen ee kicinta kala duwan iyo natiijooyinku waxay muujiyeen in dhammaan kicintaasi ay leeyihiin awood xoog leh oo H2 ah oo awood leh oo leh heerka ugu sarreeya ee ~ 100 ° C (Sawir Dheeraad ah 32).Natiijooyinka falanqaynta tirada (Jaantuska Dheeraadka ah. 33) ma muujin xidhiidh toos ah oo cad oo u dhexeeya falcelinta iyo qadarka dareeraha hydrogen.Intaa waxaa dheer, waxaan sameynay tijaabooyin D2 isotopes waxaanan helnay saameynta isotope ee kinetic (KIE) qiimaha 1.31 (TOFH / TOFD) (Jaantuska Dheeraadka ah 34), oo soo jeedinaya in firfircoonida iyo kala-soocida H2 ay muhiim yihiin laakiin maaha tallaabooyinka xaddidaya.Xisaabinta DFT ayaa la sameeyay si loo sii baaro hab-dhaqanka adsorption iyo kala qaybsanaanta hydrogen ee RuNi SAA iyo metallic Ni keligiis (Jaantuska Dheeraadka ah 35).Shaybaarada RuNi SAA, molecules H2 ayaa doorbidaya chemisorb ka badan atamyada Ru ee leh tamar adsorption ah -0.76 eV.Dabadeed, hydrogen waxa ay u kala qaybisaa laba atamka H ee firfircoon ee goobaha godan ee Ru-Ni RuNi SAA, isaga oo ka gudbaya xannibaadda tamarta 0.02 eV.Marka laga soo tago goobaha Ru, molecules H2 waxa kale oo lagu kimisorayn karaa meelaha sare ee atamka Ni ee ku dheggan Ru (tamar xayaysiis: -0.38 eV) ka dibna loo kala qaybiyo laba Hs ee goobaha godan ee Ru-Ni iyo Ni-Ni.0.06 eV.Taas beddelkeeda, caqabadaha tamarta ee xayeysiinta iyo kala-soocidda molecules H2 ee dusha Ni (111) waa -0.40 eV iyo 0.09 eV, siday u kala horreeyaan.Caqabadda tamarta aadka u hooseysa iyo kala duwanaanshiyaha aan muhiimka ahayn ayaa muujinaya in H2 ay si fudud u kala soocdo dusha sare ee Ni iyo RuNi surfactants (Ni-site ama Ru-site), taas oo aan ahayn arrin muhiim ah oo saameeya dhaqdhaqaaqeeda firfircoonida.
Dhaqdhaqaaqa firfircoon ee kooxo hawleed gaar ah ayaa muhiim u ah hydrogenation-ka xulashada ee substrates.Sidaa darteed, waxaan sameynay xisaabinta DFT si aan u baarno jaangooyooyinka suurtagalka ah ee xayeysiinta 4-NS iyo goobaha firfircoon ee RuNi SAA (111), natiijooyinka wanaajinta waxaa lagu muujiyay sawirka Dheeraadka ah. 36e), kaas oo atomyada N ay ku yaalaan goobaha godan ee Ru-Ni iyo laba atam oo O ah oo ku xidhan interface Ru-Ni waxay muujinaysaa heerka tamarta ugu hooseeya (-3.14 eV).Tani waxa ay soo jeedinaysaa nidaam xamaasad leh oo ka wanaagsan marka la barbar dhigo qaabaynta toosan iyo kuwa kale ee barbar socda (Jaantuska Dheeraadka ah 36a-d).Intaa waxaa dheer, ka dib xayeysiiska 4-HC ee RuNi SAA (111), dhererka N-O1 (L (N-O1)) ee bond kooxda nitro wuxuu kordhay 1.330 Å (Jaantus. 5a), taas oo ah wax badan. in ka badan dhererka gaaska 4- NS (1.244 Å) (Jaantuska Dheeraadka ah 37), xitaa ka badan L (N-O1) (1.315 Å) on Ni (111).Tani waxay tusinaysaa in xayaysiinta firfircoon ee N-O1 bonds ee dusha RuNi PAA si weyn loo wanaajiyay marka loo eego bilowga Ni(111).
qaabaynta xayeysiinta ee 4-HC ee Ni (111) iyo RuNi SAA (111) (Eads) oogada (dhinaca iyo aragtida sare).Ru - violet, Ni - cagaar, C - oranji, O - casaan, N - buluug, H - caddaan.b Meesha ku taal FT-IR spectra gaseous iyo chemisorbed 4-HC on surfactants monometallic Ni, Ru, RuNi (0.4 wt. %) iyo 2 wt.% RuNi, siday u kala horreeyaan.c Caadiyan goobta XANES iyo d-phase-saxey Fourier EXAFS ee Ru K- geesta 0.4 wt % RuNi PAA inta lagu jiro xayeysiinta 4-NS (RuNi SAA-4NS) iyo tillaabooyinka hydrogenation (RuNi SAA-4NS-H2) .Transformation Spectra ; ... cufnaanta samafalka ee Dowladaha (PDO) ee dusha sare ee Runi Saa (111), N-O1 ee Gaseous 4-NS iyo AdSorbed 4-NS on Runti Saa (111)."au" macneheedu waa unugyo aan sabab lahayn.
Si loo sii tijaabiyo habdhaqanka xayeysiiska ee 4-NS, goobta goobta FT-IR waxaa lagu sameeyay Ni monometallic, Ru monometallic, 0.4 wt% RuNi (SAA), iyo 2 wt% RuNi kicinta (Jaantus. 5b).FT-IR spectrum gaseous 4-NS waxay soo bandhigtay saddex astaamood oo ugu sarreeya 1603, 1528, iyo 1356 cm-1, kuwaas oo loo qoondeeyay ν(C=C), νas (NO2), iyo νs (NO2) 46,47, 48.Joogitaanka monometallic Ni, isbeddellada dhammaan saddexda qaybood ayaa la arkay: v(C=C) (1595 cm–1), νas (NO2) (1520 cm–1), iyo νs (NO2) (1351 cm–1) ., kaas oo tilmaamaya chemisorption ee kooxaha C = C iyo -NO2 ee dusha Ni (oo ay u badan tahay, qaabeynta xayeysiiska barbar socda).Muunad ka mid ah monometallic Ru, isbeddellada saddexdan qaybood (1591, 1514, iyo 1348 cm-1, siday u kala horreeyaan) marka loo eego monometallic Ni ayaa la helay, taas oo muujinaysa xayeysiis yar oo la xoojiyay ee kooxaha nitro iyo С=C bonds on Ru.Xaaladda 0.4 wt.% RuNi (SAA), ν(C=C) band waxay udub dhexaad u tahay 1596 cm-1, taas oo aad ugu dhow kooxda monometallic Ni band (1595 cm-1), taas oo muujinaysa in kooxaha vinyl ay u muuqdaan inay ku dhajiyaan Ni on RuNi. Goobaha SAA.Intaa waxaa dheer, marka la barbardhigo kicinta monometallic, xoojinta qaraabada ee νs (NO2) band (1347 cm-1) aad ayey uga daciifsan tahay νas (NO2) band (1512 cm-1) ee 0.4 wt.% RuNi (SAA) ) , kaas oo lala xiriiriyay kala-goynta dammaanadda NO-NO2 si loo sameeyo dhexdhexaadiye nitroso sida ku cad daraasadihii hore49,50.Dhacdo la mid ah ayaa sidoo kale lagu arkay muunad ka kooban RuNi oo ah 2 wt.%.Natiijooyinka kor ku xusan waxay xaqiijinayaan in saameynta isku-dhafka ah ee xarumaha bimetallic ee PAA RuNi ay kor u qaaddo polarization iyo kala-soocidda kooxaha nitro, taas oo si fiican ula socota qaabeynta xayeysiinta ugu fiican ee lagu helo xisaabinta DFT.
In goobta XAFS spectroscopy waxaa loo sameeyay si loo barto horumarka firfircoon ee qaab dhismeedka elektiroonigga ah iyo xaaladda isku xirka ee RuNi SAA inta lagu jiro xayeysiinta 4-NS iyo falcelinta kicinta.Sida laga arki karo K-edge XANES spectrum of Ru (Jaantus. 5c), ka dib xayeysiinta 4-HC, 0.4 wt.% RuNi PAA, cidhifka nuugista ayaa si weyn loogu wareejiyay tamar sare, taas oo ay la socoto korodhka xoojinta xariiqda cad, taas oo muujinaysa in noocyada Ru ee qayb ka mid ah oksaydhisku ay sabab u tahay wareejinta elektarooniga ee Ru ilaa 4-NS.Intaa waxaa dheer, marxaladda saxda ah ee Fourier ee isbeddelka EXAFS ee xayeysiiska 4-NS RuNi SAA (Jaantus. 5d) waxay muujinaysaa kor u kaca cad ee calaamadaha ~ 1.7 Å iyo ~ 3.2 Å, kaas oo la xidhiidha samaynta isuduwidda Ru-O.Xakamaynta XANES iyo EXAFS ee 0.4 wt% RuNi SAA waxay ku noqdeen xaaladdoodii asalka ahayd ka dib 30 daqiiqo oo lagu duro gaaska hydrogen.Dhacdooyinkan ayaa tilmaamaya in kooxaha nitro lagu dhajiyo goobaha Ru-O ee ku salaysan isdhexgalka elegtarooniga ah.Marka loo eego muuqaalka XAFS ee cidhifka Ni-K ee goobta (Jaantuska Dheeraadka ah. 38), isbeddel muuqda lama arkin, taas oo ay sabab u tahay saamaynta milanka atamka Ni ee wejiga tirada badan ee qaybaha Ni.Cufnaanta la saadaaliyay ee dawladaha (PDOS) ee RuNi SAA (Jaantus. 5e) waxay muujinaysaa in xaalada aan deganayn ee kooxda nitro ee ka sareysa heerka Femi ay ballaariso oo ka hooseyso heerka Femi ee gobolka adsorbed, taas oo sidoo kale muujinaysa in elektaroonnada d- gobolka RuNi SAA oo u gudbaya gobolka aan la degganayn ee -NO2.Farqiga cufnaanta kharashka (Jaantuska Dheeraadka ah. 39) iyo falanqaynta kharashka Bader (Jaantuska Dheeraadka ah 40) waxay muujinayaan in cufnaanta elektarooniga ah ee 4-NS ay ku ururto ka dib marka ay ku dhejiso dusha sare ee RuNi SAA (111).Intaa waxaa dheer, cufnaanta -NO2 ayaa si weyn u kordhay marka la barbar dhigo kooxda vinyl ee 4-NS sababtoo ah wareejinta elektarooniga ah ee Ru-Ni interface, taas oo muujinaysa firfircoonida gaarka ah ee NO bond ee kooxda nitro.
Goobta FT-IR ayaa la sameeyay si loo kormeero habka kicinta ee falcelinta hydrogenation-ka 4-NS ee shaybaarada kicinta (Jaantus. 6).Marka loo eego kicinta nikkel ee bilowga ah (Jaantus. 6a), kaliya wax yar oo hoos u dhac ku yimid cufnaanta nitro (1520 iyo 1351 cm-1) iyo C = C (1595 cm-1) xargaha ayaa la arkay markii ay dhaafeen H2 ee 12 min, kuwaas oo waxay tusinaysaa in - Dhaqdhaqaaqa NO2 iyo C=C ay yihiin kuwo daciif ah.Joogitaanka monometallic Ru (Jaantus. 6b), ν (C = C) band (ee 1591 cm-1) si degdeg ah u cidhiidhi gudaha 0-12 min, halka νs (NO2) iyo νas (NO2) si xoog leh loo dhimay. .Gaabis Tani waxay muujinaysaa firfircoonida doorbidida kooxda vinyl ee hydrogenation, taasoo horseedaysa samaynta 4-nitroethylbenzene (4-NE).Xaaladda 0.4 wt.% RuNi (SAA) (Sawir 6c), νs (NO2) band (1347 cm-1) waxay si degdeg ah u baaba'aysaa qulqulka hydrogen, oo ay la socoto si tartiib tartiib ah ν (N = O);koox cusub oo udub dhexaad u ah 1629 cm-1 ayaa sidoo kale la arkay, taas oo loo aanaynayo leexinta gariirada NH.Intaa waxaa dheer, kooxda ν (C=C) (1596 cm-1) waxay muujineysaa wax yar ka dib 12 daqiiqo.Isbeddelkan firfircooni wuxuu xaqiijinayaa polarization iyo hydrogenation of -NO2 to -NH2 by 0.4 wt% RuNi (SAA) oo ku salaysan kiimikooyinka gaarka ah ee ku wajahan 4-aminostyrene.Tusaale ahaan 2 wt.%. iyo 1348 cm-1).Tani waxay muujinaysaa in C = C iyo -NO2 ay si wax ku ool ah u shaqeeyaan sababtoo ah joogitaanka xarumaha Ru-Ru iyo Ru-Ni, siday u kala horreeyaan, taas oo u dhiganta samaynta 4-NE iyo 4-AE ee 2 wt.% RuNi kicinta.
Goobta FT-IR ee 4-NS hydrogenation ee joogitaanka monometallic Ni, b monometallic Ru, c 0.4 wt% RuNi SAA, iyo d 2 wt% RuNi ee socodka H2 ee 1700-1240 cm - Range 1 ayaa loo duubay sida gaaska falcelinta ka dib 0, 3, 6, 9 iyo 12 daqiiqo, siday u kala horreeyaan."au" macneheedu waa unugyo aan sabab lahayn.Qaybinta tamarta suurtagalka ah iyo qaabdhismeedka la hagaajiyay ee C=C hydrogenation-ka iyo NO qssion galay 4-NS on e Ni(111) iyo f RuNi SAA(111) oogada.Ru - violet, Ni - cagaar, C - oranji, O - casaan, N - buluug, H - caddaan."Xayeysiiska", "IS", "TS", iyo "FS" waxay matalaan gobolka xayeysiiska, xaaladda bilowga ah, xaaladda kala guurka, iyo gobolka ugu dambeeya, siday u kala horreeyaan.
Wadooyinka suurtagalka ah ee 4-NS u beddelka Ni (111) iyo RuNi SAA (111), oo ay ku jiraan C = C hydrogenation iyo NO bond cleavage, ayaa lagu baaray xisaabinta DFT si loo sii caddeeyo doorka muhiimka ah ee 4-NS.Qaybaha is dhexgalka Ru-Ni ee soo saarista bartilmaameedyada 4-AS.Wixii Ni (111) oogada sare (Jaantus. 6e), caqabadaha tamarta ee MAYA maqas iyo hydrogenation ee kooxaha vinyl marxaladda kowaad waa 0.74 iyo 0.72 eV, siday u kala horreeyaan, taas oo muujinaysa in hydrogenation kiimikaad ee kooxaha nitro ee 4-HC waa. aan wanaagsanayn.ee dusha nikkel monometallic.Taas beddelkeeda, xannibaadda tamarta ee kala-baxa NO ayaa kaliya 0.46 eV ka sarreeya kan RuNi SAA (111), kaas oo aad uga hooseeya kan C=C bond hydrogenation (0.76 eV) (Jaantus. 6f).Tani waxay si aan caddayn u xaqiijinaysaa in xarumaha Ru-Ni ee isdhexgalka ay si wax ku ool ah u hoos u dhigaan xannibaadda tamarta ee NO maqaska kooxaha nitro, taasoo horseedaysa hoos u dhigista kuleyl ahaan la doorbidayo ee kooxaha nitro marka la barbar dhigo kooxaha C=C ee dusha sare ee RuNi, taas oo ku raacsan natiijooyinka tijaabada.
Habka falcelinta iyo tamarta la xisaabiyay ee 4-NS hydrogenation on RuNi SAA ayaa la baaray iyadoo lagu saleynayo xisaabinta DFT (Jaantus 7), iyo qaabeynta xayeysiiska faahfaahsan ee tallaabooyinka ugu muhiimsan ayaa lagu muujiyay sawirka Dheeraadka 41. Si loo hagaajiyo barnaamijka xisaabinta, Caqabadaha tamarta soo saara ee unugyada biyaha ayaa laga saaray xisaabinta.model saxan9,17.Sida ku cad fig.7, Unugyada 4-NS waxay marka hore si siman u nuugaan ruNi surfactant, iyo laba O atomi ee kooxda nitro waxay ku xidhan yihiin xarumaha Ru-Ni ee isdhexgalka (S0; tallaabo I).Ka dib, dammaanadda NO ee ku xidhan goobta Ru waa la jabay, taas oo ay weheliso samaynta nitroso dhexdhexaad ah (C8H7NO *) ee Ru-Ni interface goobta iyo O * ee goobta Ni ee madhan (S0 → S1 iyada oo loo marayo TS1; tamarta caqabad: 0.46 eV, tallaabada labaad).O* radicals waxaa hydrogenated by atomyada H ee firfircoon si ay u sameeyaan H2O molecules oo leh 0.99 eV (S1 → S2).Caqabadaha tamarta ee hydrogenation-ka dhexe ee C8H7NO* (Tirooyinka dheeriga ah 42 iyo 43) waxay muujinayaan in atamka H ee ka soo jeeda goobaha godan ee Ru-Ni ay doorbidayaan atamka O N, taasoo keentay C8H7NOH* (S2 → S4; caqabad tamarta TS2: 0.84 eV, tallaabo III).Atomyada N ee C8H7NOH* ayaa markaa la hydrogenated si ay u sameeyaan C8H7NHOH* ka dib markii ay ka gudbeen xannibaadda 1.03 eV (S4→S6; tallaabada IV), taas oo ah tallaabada qeexida falcelinta oo dhan.Marka xigta, dammaanadda N-OH ee C8H7NHOH * ayaa lagu jabiyay is-dhexgalka Ru-Ni (S6 → S7; xannibaad tamarta: 0.59 eV; marxaladda V), ka dib OH * waxaa loo habeeyay H O (S7 → S8; exotherm: 0.31 eV). ) Intaa ka dib, N atomiyada Ru-Ni ee goobaha godan ee C8H7NH * ayaa sidoo kale lagu sameeyay hydrogenated si ay u sameeyaan C8H7NH2 * (4-AS) oo leh xannibaad tamar ah 0.69 eV (S8 → S10; tallaabo VI).Ugu dambeyntii, 4-AS iyo HO molecules ayaa laga soo saaray oogada RuNi-PAA, kataliyuhuna wuxuu ku soo noqday xaaladdiisii ​​asalka ahayd (tallaabo VII).Qaab dhismeedkan gaarka ah ee udhaxeeya hal atomiyada Ru iyo substrates Ni, oo ay weheliso saamaynta isku-dhafka ah ee doping martigeliyaha ee RuNi SAA, waxay keenaysaa waxqabadka muuqda iyo kiimikaad ee 4-NS hydrogenation.
Bariis4. Jaantuska jaantuska habka falcelinta hydrogenation-ka ee NS ilaa 4-AS ee dusha RuNi PAA.Ru - violet, Ni - cagaar, C - oranji, O - casaan, N - buluug, H - caddaan.Gelinku wuxuu muujinayaa qaybinta tamarta suurtagalka ah ee 4-NS hydrogenation ee dusha RuNi SAA (111), oo lagu xisaabiyo iyada oo ku saleysan DFT."S0″" waxay u taagan tahay xaaladda bilowga ah, iyo "S1-S10" waxay u taagan tahay dhowr gobol oo xayeysiis ah."TS" waxay u taagan tahay xaaladda kala guurka.Nambarada ku jira baararka waxay ka dhigan yihiin caqabadaha tamarta ee tallaabooyinka ugu muhiimsan, tirooyinka soo hadhayna waxay matalaan tamarta xayeysiiska ee dhexdhexaadiyeyaasha u dhigma.
Markaa, kiciyaasha RuNi SAA ayaa la helay iyadoo la adeegsanayo falcelinta korantada ee u dhaxaysa RuCl3 iyo Ni NPs ee laga helay horudhacayaasha LDH.Marka la barbardhigo hore loo soo sheegay monometallic Ru, Ni iyo kiciyayaal kale oo kala duwan, natiijada RuNi SAA waxay muujisay waxtarka sare ee 4-NS hydrogenation chemoselective (4-AS dhalidda:> 99%; Qiimaha TOF: 4293 h-1).Tilmaamaha isku dhafan oo ay ku jiraan AC-HAADF-STEM, situ CO-DRIFTS, iyo XAFS ayaa xaqiijiyay in atomyada Ru ay ka guureen Ni NP-yada heerka hal-atom ee Ru-Ni bonds, kaas oo ay la socoto wareejinta elektarooniga ee Ni ilaa Ru.Goobta XAFS, tijaabooyinka FT-IR, iyo xisaabinta DFT waxay muujisay in goobta interface Ru-Ni ay u adeegto sidii goob firfircoon oo gudaha ah oo loogu talagalay firfircoonida NO bond ee kooxda nitro;wada shaqaynta ka dhaxaysa Ru iyo goobaha Ni ee dariska ah waxay sahlaysa firfircoonida dhexdhexaadka ah iyo hydrogenation, taas oo si wayn u wanaajinaysa waxtarka catalytic.Shaqadani waxay ku siinaysaa aragti ku saabsan xidhiidhka ka dhexeeya goobaha firfircoon ee laba-jibbaaran iyo habdhaqanka catalytic ee SAA ee heerka atomiga, taas oo u gogol xaaraysa naqshadaynta macquulka ah ee kiciyayaal kale oo laba-dhinac ah oo leh xulasho la doonayo.
Dib-u-hagaajinta falanqaynta ee loo adeegsaday tijaabada waxaa laga soo iibsaday Sigma Aldrich: Al2 (SO4) 3 18H2O, sodium tartrate, CO (NH2) 2, NH4NO3, Ni (NO3) 2 6H2O, RuCl3, ethanol, 4-nitrostyrene (4- NS) , 4-aminostyrene, 4-nitroethylbenzene, 4-aminoethylbenzene iyo nitrostyrene.Biyo sifaysan ayaa loo isticmaalay dhammaan tijaabooyinka.
NiAl LDH-yada kala sarraysa ayaa la soo saaray si horudhac ah marka loo eego kobaca goobta.Marka hore, urea (3.36 g), Al2 (SO4) 3 · 18H2O (9.33 g) iyo sodium tartrate (0.32 g) ayaa lagu milmay biyaha deionized (140 ml).Xalka ka dhashay waxaa loo wareejiyay autoclave Teflon-dahaarka leh oo kuleyliyay 170 ° C 3 saacadood.Da'da soo baxday waxaa lagu dhaqay biyo nadiif ah oo si fiican loo qalajiyey, ka dib markii la dhajiyay 500 ° C (2 ° C min-1; 4 h) si loo helo amorphous Al2O3.Kadibna Al2O3 (0.2 g), Ni (NO3)2 6H2O (5.8 g) iyo NH4NO3 (9.6 g) ayaa lagu kala firdhiyey biyo saafi ah (200 ml) pH waxaa lagu hagaajiyay ~ 6.5 iyadoo lagu daray 1 mol l -1 ammonia..Joojinta waxaa lagu shubay weel waxaana lagu hayaa 90°C 48 saac si loo helo NiAl-LDH.Kadib budada NiAl-LDH (0.3 g) ayaa lagu dhimay qulqulka H2/N2 (10/90, v/v; 35 ml min-1) at 500°C ee 4 h (heerka kulaylka: 2°C min -1 ).Diyaarinta shaybaarada nikkel monometallic (Ni/Al2O3) oo lagu shubay Al2O3 aan caadi ahayn.Muunadaha bimetallic ee la xareeyay ee RuNi waxaa lagu soo saaray habka meelaynta korantada.Sida caadiga ah, muunad cusub oo Ni/Al2O3 (0.2 g) ah ayaa lagu kala firdhiyey 30 ml oo biyo saafi ah, ka dib xal RuCl3 (0.07 mmol l-1) ayaa si tartiib ah loogu daray oo si xoog leh loo walaaqay 60 daqiiqo iyadoo la ilaalinayo jawiga N2 .Da'da soo baxday ayaa la jaray, lagu dhaqay biyo saafi ah, waxaana lagu qallajiyey foorno faakuum ah 50°C ilaa 24 saac, iyadoo la helay muunad ka kooban 0.1% RuNi.Kahor qiimeynta catalytic, shaybaarada cusub ee la sameeyay ayaa si horudhac ah loo yareeyay socodka H2/N2 (10/90, v / v) ee 300 ° C (heerka kulaylka: 2 ° C min-1) 1 h, ka dibna kuleyl N2 Ku qabow heerkulka qolka.Tixraac: shaybaarro leh Ru/Al2O3 oo ka kooban 0.4% iyo 2% cufka, oo leh 0.36% cufka iyo 2.3% cufka, waxaa lagu diyaariyey roobab roobab iyo kulayl 300 °C ah (isticmaalka H2/ N2: 10/90, v/v, heerka kulaylka: 2 °C min-1) 3 saacadood.
Tijaabooyin kala duwanaansho raajada (XRD) ayaa lagu sameeyay Bruker DAVINCI D8 ADVANCE diffractometer oo leh isha shucaaca Cu Kα (40 kV iyo 40 mA).Shimadzu ICPS-7500 Balaasma Atomic Emission Spectrometer (ICP-AES) ayaa la isticmaalay si loo go'aamiyo tirada dhabta ah ee canaasirta ee muunado kala duwan.Sawirada sawir-qaadista elektaroonigga ah (SEM) ayaa lagu sawiray iyada oo la isticmaalayo mikroskoob elektaroonig ah oo Zeiss Supra 55 ah.Tijaabooyinka adsorption-desorption N2 ayaa lagu sameeyay aaladda Micromeritics ASAP 2020 waxaana meel gaar ah oo dusha sare ah lagu xisaabiyay iyadoo la adeegsanayo habka dhibcaha badan ee Brunauer-Emmett-Teller (BET).Sifooyinka gudbinta elektaroonigga ah (TEM) ayaa lagu sameeyay JEOL JEM-2010 mikroskoob-gudbineed heer sare ah.Xagalka Sare ee la saxay gudbinta Scaning Electron Microscope Dark Field (AC-HAADF) - STEM oo leh FEI Titan Cube Themis G2 300 oo leh saxaha aberration spherical iyo tamarta kala firdhisan ee Raajo Spectroscopy (EDS) iyo JEOL JEM-ARM200F qalab) iyo EDS cabbirida khariidad .Qaab dhismeedka Fiican ee nuugista raajada (XAFS) ee goobta K-cidhifka Ru iyo Ni K-geeska ayaa lagu cabbiray kanaalada 1W1B iyo 1W2B ee Xarunta Shucaaca ee Beijing Synchrotron (BSRF) ee Machadka Fiisigiska Tamarta Sare (IHEP), Shiinaha .Akademiyada Sayniska (KAN).Chemisorption CO Pulsed iyo Heer-ku-barnaamijka Desorption Haydarojiin (H2-TPD) tijaabooyinka ayaa lagu sameeyay aaladda Micromeritics Autochem II 2920 iyadoo la adeegsanayo aaladaha kuleylka kuleylka (TCD).Tijaabooyinka goobta DRIFTS iyo FT-IR waxaa lagu sameeyay Bruker TENSOR II spectrometer infrared oo ku qalabaysan unug falcelin ah oo la bedelay iyo qalabka wax baadha ee MCT oo aad xasaasi u ah.Hababka sifada oo faahfaahsan ayaa lagu sifeeyay Macluumaadka Dheeraadka ah.
Marka hore, substrate-ka (4-NS, 1 mmol), dareeraha (ethanol, 8 ml) iyo kicinta (0.02 g) ayaa si taxadar leh loogu daray 25 ml autoclave birta aan lahayn.Reactor-ka ayaa markaa si buuxda loogu nadiifiyay 2.0 MPa (> 99.999%) hydrogen 5 jeer, ka dibna la cadaadiyay oo lagu xidhay 1.0 MPa oo leh H2.Dareen-celinta waxaa lagu sameeyay 60 ° C xawaare kicin joogto ah oo ah 700 rpm.Falcelinta ka dib, alaabooyinka ka soo baxay waxaa lagu aqoonsaday GC-MS waxaana si qiyaas ah loo falanqeeyay iyadoo la adeegsanayo Shimadzu GC-2014C gaaska chromatography system oo ku qalabaysan GSBP-INOWAX column capillary (30 m × 0.25 mm × 0.25 mm) iyo qalabka FID.Beddelka 4-nitrostyrene iyo xulashada wax soo saarka ayaa loo go'aamiyay sida soo socota:
Qiimaha soo noqnoqda (TOF) waxaa loo xisaabiyay mol 4-NS oo loo beddelay goobihii birta mol saacaddiiba (mol4-NS mol-1 h-1) oo ku salaysan beddelka 4-NS hoose (~ 15%).Sida tirada Ru noodyada, Ru-Ni interface noodes iyo tirada guud ee atamka biraha dusha.Tijaabada dib-u-warshadaynta, kicinta waxa lagu soo ururiyay centrifugation ka dib falcelinta, lagu dhaqay saddex jeer ethanol, ka dibna dib loogu soo bandhigay autoclave wareegga xiga ee catalytic.
Dhammaan xisaabinta aragtida shaqeynta cufnaanta (DFT) ayaa la sameeyay iyadoo la adeegsanayo xirmada jilitaanka Vienna ab initio (VASP 5.4.1).Shaqada PBE ee Qiyaasta Guud ee Gradient (GGA) waxa loo isticmaalaa in lagu qeexo isweydaarsiga elektarooniga ah iyo xaaladaha isku xidhka.Habka Projector Augmented Wave (PAW) waxaa loo isticmaalaa in lagu qeexo isdhexgalka ka dhexeeya nuclei-yada atomiga iyo elektarooniga.Habka Grimm DFT-D3 wuxuu qeexayaa saamaynta isdhexgalka van der Waals ee u dhexeeya substrate-ka iyo is-dhexgalka.Xisaabinta Caqabadaha Tamarta iyadoo lagu fuulayo Xadhkaha Laastikada ah ee Kor u Qaadista Sawirka (CI-NEB) iyo Hababka Dimer.Falanqaynta soo noqnoqda ee miyir-beelka ayaa la sameeyay, iyada oo la xaqiijinayo joogitaanka hal mar oo kaliya oo male-awaal ah xaalad kasta oo kala-guur ah (Tirooyinka dheeriga ah 44-51).Xisaabinta faahfaahsan ayaa lagu qeexay macluumaadka dheeraadka ah.
Xogta ugu muhiimsan ee taageerta shirqoollada maqaalkan waxaa lagu bixiyaa xogta xogta isha.Xogta kale ee la xidhiidha daraasaddan ayaa laga heli karaa qorayaasha kala duwan marka la eego codsi macquul ah.Maqaalkani waxa uu bixiyaa xogta asalka ah.
Korma A. iyo Serna P. Chemoselective hydrogenation ee xeryahooda nitro oo leh qalab dahab ah oo la taageeray.Sayniska 313, 332-334 (2006).
Formenti D., Ferretti F., Sharnagle FK iyo Beller M. Yaraynta xeryahooda nitro iyadoo la isticmaalayo 3d biraha birta ah.Kiimiko119, 2611–2680 (2019).
Tan, Y. iyo al.Au25 nanoclusters oo lagu taageeray ZnAl hydrotalcite sidii horudhac u ah hydrogenation chemoselective of 3-nitrostyrene.Angie.Kiimikogudaha Ed.56, 1–6 (2017).
Zhang L, Zhou M, Wang A, Zhang TKiimiko120, 683–733 (2020).
Sun, K. iyo al.Monoatomic rhodium kiciyayaal lagu soo koobay zeolite: Wax soo saar hydrogen oo hufan iyo hydrogenation cascade cascade ee xeryahooda nitroaromatic.Angie.Kiimikogudaha Ed.58. 18570-18576 (2019).
Tian, ​​S.iyo al.Diatomic Pt heterogeneous kataliye leh oo leh hawl karsi heer sare ah oo loogu talagalay hydrogenation-ka xulashada iyo epioxidation.Isbaheysiga qaranka.12, 3181 (2021).
Wang, Yu.iyo al.hydrogenation-ka kiimikaad ee nitroarenes ee birta nanosized(III)–OH-platinum interfaces.Angie.Kiimikogudaha Ed.59, 12736–12740 (2020).
Wei, H. iyo al.FeOx waxay taageertay platinum monatomic iyo kicinta pseudomonoatomic ee hydrogenation chemoselective ee xeryahooda nitroaromatic functionalized.Isbaheysiga qaranka.5, 5634 (2014).
Khan, A. iyo al.Kala soocida atamka Pt ee isdaba jooga iyo samaynta nanoparticles intermetallic Pt-Zn si loo habeeyo xulashada 4-nitrophenylacetylene hydrogenation.Isbaheysiga qaranka.10, 3787 (2019).
Wang, K. iyo al.Eeg ku tiirsanaanta cabbirka aan caadiga ahayn ee kicinta Pt ee monatomic Pt ee lagu taageeray CeO2.Kiimikada 6, 752–765 (2020).
Feng Yu iyo al.Baahida nidaamka hydrogenation ultra-xulashada iyadoo la adeegsanayo nanocubes Pd-Cd oo si fiican loo habeeyay.Jam.Kiimikobulshada.142, 962–972 (2020).
Fu, J. iyo al.Saamaynta isku-dhafan ee catalysis ee la xoojiyey ee kicinta monatomic double.Catalan SAU.11, 1952-1961 (2021).
Liu, L. iyo al.Go'aaminta kobcinta atomyada birta ah ee kala duwan iyo nanoclusters hoos yimaada xaaladaha falcelinta: waa maxay goobaha firfircoonida shaqada?Catalan SAU.9, 10626-10639 (2019).
Yang, N. iyo al.Amorphous/crystalline heterogeneous palladium nanosheets: hal-dheri isku dar ah iyo falcelin hydrogenation ah oo aad u xushay.Jaamacad sare.30, 1803234 (2018).
Gao, R. iyo al.Jebinta is-dhaafsiga u dhexeeya xulashada iyo dhaqdhaqaaqa kicinta hydrogenation-ka ee nikkel-ku-saleysan iyadoo la hagaajinayo saameynta steric-ka ah iyo xarumaha d-band.Cilmi sare.6, 1900054 (2019).
Lee, M. iyo al.Isha firfircoon ee Co-NC ee kiciyaasha hydrogenation chemoselective ee xeryahooda nitroaromatic.Catalan SAU.11, 3026–3039 (2021).