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Nhazi na mmepe nke ihe na-eme ka ọrụ dị elu enwetala nlebara anya dị ukwuu na mmeghachi omume hydrogenation nhọrọ mana ọ ka bụ nnukwu ihe ịma aka.N'ebe a, anyị na-akọ otu monotomic RuNi alloy (SAA) nke ru atọm n'otu n'otu na-enweghị ike ime n'elu Ni nanoparticles site na nhazi Ru-Ni, nke a na-ejikọta ya na nnyefe eletrọn si subsurface Ni ruo Ru.N'ihe ọmụma anyị, ihe kacha mma 0.4% RuNi SAA n'otu oge gosipụtara ọrụ dị elu (uru TOF: 4293 h-1) na chemoselectivity maka ịhọrọ hydrogenation nke 4-nitrostyrene na 4-aminostyrene (mpụta:> 99%), ọkwa kachasị elu site na. tụnyere mara heterogeneous catalysts.N'ime nnwale ọnọdụ na ngụkọ usoro ihe ngosi na-egosi na saịtị interface Ru-Ni, dị ka saịtị na-arụ ọrụ n'ime, na-akwalite nbibi nke ọnweghị nkekọ yana obere ihe mgbochi ike nke 0.28 eV.Na mgbakwunye, synergistic Ru-Ni catalysis na-akwado nguzobe nke etiti (C8H7NO * na C8H7NOH *) ma na-eme ka usoro ikpebi ọnụego (hydrogenation nke C8H7NOH*).
Amines aromatic na-arụ ọrụ, ihe mgbochi ụlọ dị mkpa nke kemịkalụ dị mma, nwere ngwa ụlọ ọrụ dị mkpa na mmepụta nke ọgwụ, agrochemicals, pigmenti na polymers1,2,3.Hydrogenation catalytic nke ogige nitroaromatic dị ngwa ngwa n'elu ihe ndị na-akpali akpali adọtala nlebara anya dị ukwuu dị ka usoro enyi na gburugburu ebe obibi na nke enwere ike ịmegharị maka njikọ nke amines nwere uru agbakwunyere4,5,6,7.Agbanyeghị, mbelata chemoselective nke otu -NO2 ka ị na-ejigide otu ndị ọzọ reducible dị ka alkenes, alkynes, halogens, ma ọ bụ ketones bụ ihe a na-achọsi ike mana kama ọrụ siri ike8,9,10,11.Ya mere, iji ezi uche eme ihe dị iche iche na-akpali akpali maka mbelata kpọmkwem nke -NO2 otu na-enweghị emetụta agbụ ndị ọzọ reducible bụ ihe na-achọsi ike12,13,14.A enyochala ọtụtụ ihe ndị na-eme ihe na-enweghị ọla na-eme ka hydrogenation nke nitroarenes dị mma, mana ọnọdụ mmeghachi omume siri ike na-egbochi ngwa ha sara mbara15,16.Ọ bụ ezie na ihe ndị na-eme ka ọla dị mma (dị ka Ru17, Pt18, 19, 20 ma ọ bụ Pd21, 22, 23) na-arụ ọrụ n'okpuru ọnọdụ mmeghachi omume dị nro, ha na-ata ahụhụ site na ọnụ ahịa dị elu, suboptimal selectivity, na obere atom itinye n'ọrụ.Ya mere, inweta ihe na-arụsi ọrụ ike na nke chemoselective site na nhazi ezi uche na nhazi nke ọma nke nhazi ahụ ka bụ nnukwu ihe ịma aka24,25,26.
Monatomic Alloy (SAA) ihe na-eme ka ọ nwee arụmọrụ ọla dị mma, nhazi geometric na eletrọnịkị pụrụ iche, na-enye saịtị ndị pụrụ iche na-arụ ọrụ, ma na-enye arụmọrụ catalytic pụtara ìhè site n'imebi àgwà njiri mara linear27,28,29,30,31.Atọm otu doped na atom metal host na SAA nwere ike ije ozi dị ka saịtị abụọ na-arụ ọrụ, na-eme ka ịgbalite ọtụtụ mkpụrụ ma ọ bụ ikwe ka usoro mmeghachi omume elementrị dị iche iche mee na saịtị dị iche iche32,33,34.Na mgbakwunye, mkpakọrịta heterometallic dị n'etiti atọm metal adịghị ọcha na igwe ndị ọbịa nwere ike iduga mmetụta synergistic idiosyncratic, ọ bụ ezie na nghọta nke mmetụta synergistic dị otú ahụ n'etiti saịtị abụọ nke saịtị ọla na ọkwa atọm ka na-ese okwu35,36,37,38.Maka hydrogenation nke nitroarenes na-arụ ọrụ, a ga-emerịrị usoro eletrọnịkị na geometric nke saịtị ndị na-arụ ọrụ n'ụzọ iji mee ka ịgbalite otu nitro naanị.Dị ka a na-achị, a na-agbasakarị otu nitro-enweghị eletrọn na mpaghara nucleophilic nke elu ihe na-akpata, ebe n'okporo ụzọ hydrogenation na-esote, catalysis nkwado nke saịtị ndị agbata obi ga-arụ ọrụ dị mkpa n'ịchịkwa mmeghachi omume na chemoselectivity4,25.Nke a kpaliri anyị inyocha SAA catalysts dị ka onye na-ekwe nkwa maka imeziwanye nrụpụta catalytic nke chemoselective hydrogenation nke ogige nitroaromatic, yana n'ihu n'ịkọwa mmekọrịta dị n'etiti nhazi saịtị na-arụ ọrụ na arụ ọrụ nke atomic scale catalytic.
N'ebe a, a na-akwado ihe ndị na-emepụta ihe na-adabere na monatomic RuNi alloys na-adabere na usoro nhazi nke abụọ, gụnyere mgbanwe nhazi-topological nke Layered double hydroxide (LDH) na-esote ọgwụgwọ electro-ntugharị.RuNi SAA na-egosipụta arụmọrụ catalytic pụrụ iche (> 99% mkpụrụ) maka chemoselective hydrogenation nke 4-nitrostyrene na 4-aminostyrene na ntụgharị ntụgharị (TOF) ruru ~ 4300 mol-mol Ru-1 h-1, nke kachasị elu. Ọkwa n'etiti ihe na-akpata dị iche iche debara aha n'okpuru ọnọdụ mmeghachi omume yiri nke ahụ.Electron microscopy na spectroscopic characterization gosiri na dịpụrụ adịpụ Ru atọm na-agbasasị n'elu Ni nanoparticles (~ 8 nm), na-eme ka a kwụsie ike Ru-Ni nchikota, na-akpata na-adịghị mma Ru saịtị (Ruδ-) n'ihi na eletrọn nnyefe si subsurface Ni ka Ru. .Na ọnọdụ FT-IR, ọmụmụ XAFS na ngụkọ njupụta arụmọrụ (DFT) kwadoro na saịtị dị na interface Ru-Ni dị ka saịtị na-arụ ọrụ n'ime na-akwado nitro.Adsorption arụ ọrụ (0.46 eV) dị iche na nke ihe na-eme ka nickel monometallic.(0.74V).Na mgbakwunye, nkesa hydrogen na-apụta na ọnọdụ Ni gbara agbata obi, na-esote hydrogenation nke intermediates (C8H7NO * na C8H7NOH *) na ọnọdụ Ruδ.Mmetụta synergistic nke nkwado doping na RuNi SAA na-akpata na-arụpụta ọrụ nitroarenes hydrogenation pụtara ìhè na nhọrọ nhọrọ, nke enwere ike ịgbatị ya na ihe mkpali ọla ndị ọzọ na-adịghị ahụkebe ejiri mee ihe na mmeghachi omume mmetụta.
Dabere na mgbanwe nke structural topology nke Layered double hydroxide (LDH) precursors, anyị kwadoro monometallic Ni nke etinyere na amorphous Al2O3 substrates.Mgbe nke ahụ gasịrị, a setịpụ nke RuNi / Al2O3 bimetallic samples na dị iche iche ru ọdịnaya (0.1-2 wt%) e n'ụzọ ziri ezi synthesized site electrodisplacement na-edebe Ru atọm n'elu Ni nanoparticles (NPs) (Fig. 1a).Ntụle ihe nleba anya nke atọmịk emission spectrometry (ICP-AES) jikọtara nke ọma nyere n'ụzọ doro anya ihe mejupụtara elementrị nke Ru na Ni na nlele ndị a (Table 1), nke dị nso na ntinye akwụkwọ nri.Ihe onyonyo SEM (Ntinye mgbakwunye 1) na nsonaazụ BET (Ntinye mgbakwunye 2-9 na tebụl mgbakwunye 1) na-egosi n'ụzọ doro anya na usoro morphological na mpaghara elu akọwapụtara nke ihe nlele RuNi / Al2O3 adịghị enwe mgbanwe doro anya n'oge ọgwụgwọ electrochemical.- usoro ịkwaga.Usoro X-ray (Fig 1b) na-egosi usoro ntụgharị uche dị iche iche na 2θ 44.3 °, 51.6 °, na 76.1 °, na-egosi usoro (111), (200), na (220) nke ụdị Ni (JCPDS 004-0850). ).N'ụzọ doro anya, ihe nlele RuNi anaghị egosi nhụsianya nke ru ọla ma ọ bụ oxidized, na-egosi nnukwu mgbasa nke ụdị Ru.Nleba eletrọnịkị microscopy (TEM) nha nke monometallic Ni na RuNi samples (Fig. 1c1-c8) na-egosi na nickel nanoparticles na-agbasasị nke ọma na enweghị ike ime na nkwado Al2O3 amorphous nwere nha nha nha (7.7-8.3 nm).Ihe oyiyi HRTEM (Figs 1d1-d8) na-egosi otu oge nkedo nke ihe dịka 0.203 nm n'ime ihe atụ Ni na RuNi, nke kwekọrọ na ụgbọ elu Ni (111), Otú ọ dị, ọnụ ọgụgụ lattice nke akụkụ Ru na-anọghị.Nke a na-egosi na ru atọm na-ukwuu agbasasị n'elu sample na-adịghị emetụta Ni lattice oge.Ka ọ dị ugbu a, 2 wt% Ru / Al2O3 mebere site na usoro nkwụnye ego dịka njikwa, nke a na-ekesa ụyọkọ Ru n'otu n'otu n'elu ala nke Al2O3 (Fig 10-12).
a Atụmatụ nke njikọ ụzọ maka RuNi/Al2O3 samples, b X-ray diffraction ụkpụrụ nke Ni/Al2O3 na dị iche iche RuNi/Al2O3 samples.c1-c8 TEM na d1-d8 HRTEM onyonyo grating nwere nkesa nha nha nke monometallic Ni, 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0, 8% wt., 1 wt.Onyonyo nkewapụrụ.% na 2 wt.% RuNi.“au” pụtara nkeji aka aka ike.
A mụrụ ọrụ catalytic nke ihe nlele RuNi site na chemoselective hydrogenation nke 4-nitrostyrene (4-NS) ruo 4-aminostyrene (4-AS).Ntughari 4-NS na mkpụrụ ala Al2O3 dị ọcha bụ naanị 0.6% mgbe awa 3 gachara (Tụlụ mgbakwunye 2), na-egosi ntakịrị mmetụta catalytic nke Al2O3.Dị ka e gosiri na fig.2a, ihe mmalite nickel mbụ gosipụtara ọrụ catalytic dị oke ala yana ntụgharị 4-NS nke 7.1% mgbe awa 3 gachara, ebe enwere ike nweta ntụgharị 100% n'ihu monometallic Ru catalyst n'okpuru otu ọnọdụ ahụ.All RuNi catalysts gosiri mmụba dị ukwuu nke ọrụ hydrogenation (mgbanwe: ~ 100%, 3 h) ma e jiri ya tụnyere ihe atụ monometallic, na ọnụego mmeghachi omume na-ejikọta ya na ọdịnaya Ru.Nke a pụtara na irighiri ihe Ru na-arụ ọrụ dị mkpa na usoro hydrogenation.N'ụzọ na-akpali mmasị, ngwaahịa selectivity (Fig 2b) dịgasị iche iche dabere na ihe mkpali.Maka ihe na-eme ka nickel dị ọcha na-adịghị arụ ọrụ, ngwaahịa bụ isi bụ 4-nitroethylbenzene (4-NE) (nhọrọ: 83.6%) na nhọrọ nke 4-AC bụ 11.3%.N'ihe banyere monometallic Ru, njikọ C = C na 4-NS na-enwe ike ịnweta hydrogenation karịa -NO2, na-eduga na nhazi 4-nitroethylbenzene (4-NE) ma ọ bụ 4-aminoethylbenzene (4-AE);Nhọrọ nke 4-AC bụ naanị 15.7%.N'ụzọ dị ịtụnanya, RuNi catalysts nwere obere ọdịnaya ru dị ala (0.1-0.4 wt%) gosipụtara ezigbo nhọrọ (> 99%) na 4-aminostyrene (4-AS), na-egosi na ọ bụ NO2 na ọ bụghị vinyl, bụ chemoselective pụrụ iche.Mgbe ọdịnaya nke Ru gafere 0.6 wt.%, selectivity nke 4-AS belatara nke ọma na-abawanye loading nke Ru, mgbe selectivity nke 4-AE mụbara kama.Maka ihe na-akpali akpali nwere 2 wt% RuNi, ma otu nitro na vinyl nwere nnukwu hydrogen nwere nnukwu nhọrọ na 4-AE nke 98%.Iji na-amụ mmetụta nke Ru dispersion ala na catalytic mmeghachi omume, 0,4 wt% Ru / Al2O3 samples e njikere (Mgbakwunye Figures 10, 13 na 14) nke Ru ahụ na-akasị agbasasị dị ka onye atọm sochiri a ole na ole Ru ụyọkọ.(quasi-atomic Ru).Arụ ọrụ catalytic (Mgbakwunye 2) na-egosi na 0.4 wt% Ru / Al2O3 na-eme ka 4-AS selectivity (67.5%) ma e jiri ya tụnyere 2 wt% Ru / Al2O3 sample, mana ọrụ ahụ dị ala (ntụgharị: 12.9).%;3 awa).Dabere na ọnụ ọgụgụ nke saịtị igwe dị n'elu nke CO pulsed chemisorption nha, a na-enweta ugboro ole ntụgharị (TOFmetal) nke RuNi catalyst na ntụgharị 4-NS dị ala (Mgbakwunye Fig. 15), nke gosipụtara omume mbụ na-abawanye ụba. na mgbe ahụ ka ibelata na-abawanye na-abawanye na Ru loading (Mgbakwunye Fig. 16).Nke a na-egosi na ọ bụghị saịtị igwe elu niile na-arụ ọrụ dị ka saịtị na-arụ ọrụ maka RuNi.Tụkwasị na nke ahụ, a gbakọọ TOF nke RuNi catalyst site na saịtị Ru iji gosikwuo ọrụ catalytic ya (Fig 2c).Ka ọdịnaya nke Ru na-abawanye site na 0.1 wt.% ruo 0.4 wt.% RuNi catalysts gosiri fọrọ nke nta mgbe nile TOF ụkpụrụ (4271-4293 h-1), nke na-egosi na localization nke ru irighiri na atomic dispersion (ikekwe na nguzobe nke RuNi SAA).) ma na-eje ozi dị ka saịtị na-arụsi ọrụ ike.Otú ọ dị, na mmụba ọzọ na ntinye nke Ru (n'ime 0.6-2 wt%), uru TOF na-ebelata nke ukwuu, nke na-egosi mgbanwe n'ime ihe dị n'ime ime ụlọ ọrụ (site na atomiki dispersion na Ru nanoclusters).Tụkwasị na nke ahụ, na ihe ọmụma anyị, TOF nke 0.4 wt% RuNi (SAA) na-eme ka ọ bụrụ ọkwa kachasị elu n'etiti ihe ndị na-emepụta ígwè na-akọ na mbụ n'okpuru ọnọdụ mmeghachi omume yiri nke ahụ (Mgbakwunye 3), na-egosipụtakwa na monoatomic RuNi alloys na-enye ihe ndị na-emepụta ihe dị mma.ihe nlegharị anya.Ọnụọgụ mgbakwunye 17 na-egosi arụmọrụ catalytic nke 0.4 wt% RuNi (SAA) na-eme ka ọ bụrụ nrụgide dị iche iche na okpomọkụ nke H2, ebe H2 mgbali nke 1 MPa na mmeghachi omume okpomọkụ nke 60 Celsius C na-eji dị ka ihe mmeghachi omume kachasị mma.sample nwere RuNi 0.4 wt.% (Fig. 2d), ọnweghị mbelata dị ukwuu na ọrụ na mkpụrụ nke a hụrụ n'ime usoro okirikiri ise sochiri.Onyonyo X-ray na TEM nke 0.4 wt% RuNi catalyst ejiri mee ihe mgbe okirikiri 5 gasịrị (Mgbakwunye 18 na 19) egosighi mgbanwe dị ịrịba ama na nhazi kristal, na-egosi nkwụsi ike dị elu nke mmeghachi omume hydrogenation nhọrọ.Na mgbakwunye, 0.4 wt% RuNi (SAA) na-eme ka ọ na-enyekwa ezigbo mkpụrụ nke amines maka chemoselective hydrogenation nke ogige nitroaromatic ndị ọzọ nwere halogens, aldehydes, na hydroxyl otu (Nkwupụta 4), na-egosi na ọ dị mma.
ntụgharị nke Catalytic na b nkesa 4-nitrostyrene hydrogenation ngwaahịa n'ihu monometallic Ni, Ru, na RuNi catalysts nwere ọdịnaya Ru dị iche iche (0.1-2 wt%), c na oke ike ike, ntụgharị ntụgharị (TOF) na RuNi. catalysts c dabere na Ru kwa mole.Nwalee maka ohere nke ijikwa 0.4 wt.% RuNi na-akwalite okirikiri catalytic ise na-esochi.ln (C0 / C) dabere na oge mmeghachi omume nke hydrogenation nke e-nitrobenzene na f-styrene na ngwakọta nke nitrobenzene na styrene (1: 1).Ọnọdụ mmeghachi omume: 1 mmol reagent, 8 ml ihe mgbaze (ethanol), 0.02 g catalyst, 1 MPa H2, 60°C, 3 awa.A kọwapụtara ogwe mperi mperi dị ka ọkọlọtọ ọkọlọtọ nke emegharịgharị atọ.
Iji nyochaa ọdịiche dị ịrịba ama chemoselective dị iche iche, a na-eme hydrogenation nke ngwakọta nke styrene na nitrobenzene (1: 1) na ọnụnọ monometallic catalysts Ni, Ru, 0.4 wt% RuNi, na 2 wt% RuNi, n'otu n'otu (Mgbakwunye Fig). 20).Ọ bụ ezie na chemoselectivity nke mmeghachi omume hydrogenation nke otu ndị na-arụ ọrụ na-agbanwe agbanwe, n'ezie enwere ụfọdụ ọdịiche dị na nhọrọ nke intramolecular na intermolecular hydrogenation n'ihi mmetụta allosteric molecular.Dị ka e gosiri na fig.2e,f, curve ln (C0/C) na oge mmeghachi omume na-enye ahịrị kwụ ọtọ site na mmalite, na-egosi na ma nitrobenzene na styrene bụ mmeghachi omume nke mbụ.Monometallic nickel catalysts gosipụtara ọnụọgụ hydrogenation dị ala maka ma p-nitrobenzene (0.03 h-1) na styrene (0.05 h-1).N'ụzọ doro anya, a na-enweta ọrụ styrene hydrogenation ka mma (ọnụego mgbe niile: 0.89 h-1) na Ru monometallic catalyst, nke dị elu karịa ọrụ hydrogenation nitrobenzene (ọnụego mgbe niile: 0.18 h-1).N'ihe gbasara ihe mkpali nwere RuNi(SAA) 0.4 wt.% nitrobenzene hydrogenation bụ dynamically mma karịa styrene hydrogenation (ọnụego mgbe niile: 1.90 h-1 vs. 0.04 h-1), na-egosi mmasị maka -NO2 otu.n'elu C hydrogenation = njikọ C. Maka ihe na-akpali akpali na 2 wt.% RuNi, ọnụego hydrogenation mgbe niile nke nitrobenzene (1.65 h-1) belatara ma e jiri ya tụnyere 0.4 wt.%.h-1).Nke a na-egosikwa na site na mmetụta synergistic n'etiti Ni na Ru, ọrụ catalytic na chemoselectivity kwupụta -NO2 dị iche iche na-abawanye nke ukwuu ma e jiri ya tụnyere RuNi SAA.
Iji anya chọpụta dispersion steeti Ru na Ni ogige, ihe Onyonyo usoro na-eji elu-n'akuku mgbanaka ọchịchịrị scanning eletrọnịkị microscopy na aberration mgbazi (AC-HAADF-STEM) na mmewere nkewa site ike dispersive spectroscopy (EDS) e rụrụ.Maapụ elemental EMF nke ihe nlele nwere 0.4 wt% RuNi ọdịnaya (Fig 3a, b) na-egosi na Ru na-agbasasịkwa n'otu n'otu na nickel nanoparticles, mana ọ bụghị na mkpụrụ ala Al2O3, ihe oyiyi AC-HAADF-STEM kwekọrọ (Fig. 3c) na-egosi, Ọ nwere ike ịhụ na elu nke Ni NP nwere ọtụtụ na-egbuke egbuke tụrụ nke atomic size nke Ru atọm (akara-acha anụnụ anụnụ akụ), mgbe ọ dịghị ụyọkọ ma ọ bụ Ru nanoparticles hụrụ.Fig. 3d), na-egosi nguzobe nke monatomic RuNi alloys.Maka nlele nwere RuNi 0.6 wt.% (Fig 3e), otu Ru atoms na obere obere akụkụ ru na-ahụ na Ni NPs, nke na-egosi ntakịrị nchịkọta nke Ru atom n'ihi ụbara ibu.N'ihe banyere ihe nlele na 2 wt% RuNi ọdịnaya, ọtụtụ nnukwu ụyọkọ Ru na Ni NP dị na HAADF-STEM oyiyi (Fig 3f) na EDS elemental mapping (Mgbakwunye 21), na-egosi nnukwu nchịkọta nke Ru. .
ihe oyiyi HAADF-STEM, b ihe oyiyi eserese EDS kwekọrọ, c elu mkpebi AC-HAADF-STEM oyiyi, d nnukwu ihe oyiyi STEM na nkesa ike kwekọrọ nke 0.4 wt% RuNi sample.(e, f) AC-HAADF-STEM onyonyo nke ihe atụ nwere 0.6 wt.% RuNi na 2 wt.% RuNi, n'otu n'otu.
N'iji ya tụnyere Ni / Al2O3 na Ru / Al2O3 samples, DRIFTS spectra of CO adsorption in situ (Fig. 4a) ka a na-amụkwu nkọwa nhazi nke ihe nlele nwere 0.4 wt.%, 0,6 wt.% na 2 wt.% RuNi.Mgbasa ozi CO na ihe nlele Ru/Al2O3 na-enye ọnụ ọgụgụ kachasị elu na 2060 cm-1 yana ọnụ ọgụgụ ọzọ sara mbara na 1849 cm-1 sitere na mgbasa ozi CO linear na Ru na ijikọ na atọm ru gbara agbata obi abụọ, n'otu n'otu CO39,40.Maka ihe atụ nke monometallic Ni, a na-ahụ elu dị elu naanị na 2057 cm-1, nke a na-akpọ CO41,42 linear na mpaghara nickel.Maka ihe atụ RuNi, na mgbakwunye na isi elu na 2056 cm-1, enwere ubu dị iche iche dabere na ~ 2030 cm-1.A na-eji usoro kachasị elu nke Gaussian mee ihe iji mebie nkesa nke ihe atụ RuNi na 2000-2100 cm-1 na nkesa CO na mpaghara Ni (2056 cm-1) na mpaghara Ru (2031-2039 cm).A na-ejikọta ọnụ ọnụ elu abụọ n'ahịrị - 1) (Fig 4b).N'ụzọ na-akpali mmasị, site na ihe nlele Ru / Al2O3 (2060 cm-1) na ihe nlele RuNi (2031-2039 cm-1), ọnụ ọgụgụ CO nke njikọ njikọ na mpaghara Ru na-enweta nnukwu redshift ma na-abawanye na ọdịnaya Ru na-abawanye.Nke a na-egosi mmụba eletrọnịkị nke ru n'ime ihe nlele RuNi, nke bụ nsonaazụ nnyefe eletrọn site na Ni ruo Ru, na-abawanye nzaghachi d-π elektrọn site na Ru gaa na mgbochi CO 2π* orbital.Na mgbakwunye, maka ihe nlele nwere 0.4 mass% RuNi, ọ nweghị ọnụ ọgụgụ mgbasa ozi mgbasa ozi ka hụrụ, na-egosi na ru ahụ dị ka Ni atom (SAA) dịpụrụ adịpụ.N'ihe banyere ihe atụ na 0,6 wt.% RuNi na 2 wt.% RuNi, ọnụnọ nke bridging CO na-akwado ịdị adị nke Ru multimers ma ọ bụ ụyọkọ, nke dị na nkwekọrịta dị mma na nsonaazụ AC-HAADF-STEM.
a Na ọnọdụ CO-DRIFTS ụdịdị Ni / Al2O3, Ru / Al2O3 na 0.4 wt.%, 0.6 wt.%, 2 wt.% RuNi samples na helium gas eruba na nso 2100-1500 cm-1 maka 20 min.b Scaled na Gaussian dabara n'ụdị nke ihe nlele RuNi/Al2O3 nwere ọnọdụ kachasị elu na FWHM.c N'ebe Ru K-ọnụ XANES spectra na d EXAFS Fourier na-agbanwe ụdịdị ụdịdị dị iche iche.Mgbanwe wavelet dị arọ nke K2 nke akara XAFS K-edge Ru dabere na Morlet wavelet maka e Ru samples sitere na e Ru foil, f 0.4 wt% RuNi na g RuO2.“au” pụtara nkeji aka aka ike.
Haziri n'ụdị nnabata X-ray dị n'ọnọdụ dị n'ụdị X-ray absorption structure (XANES) ka a na-eme iji mụọ usoro eletrọnịkị na nke geometric nke ihe nlele RuNi jiri ihe nlele Ru foil na RuO2.Dị ka e gosiri na fig.4c, ka Ru loading na-ebelata, ike nke ahịrị ọcha ji nwayọọ nwayọọ na-ebelata site na ihe nlele Ru/Al2O3 gaa na nlele RuNi.Ka ọ dị ugbu a, ike nke ahịrị ọcha nke XANES spectrum na K-akụkụ nke Ni na-egosi ntakịrị mmụba site na mbụ Ni sample na ihe nlele RuNi (Mgbakwunye 22).Nke a na-egosi mgbanwe na njupụta eletrọn na nchikota nke ogige Ru.Dị ka e gosiri na X-ray photoelectron spectroscopy (XPS) spectra (Mgbakwunye 23), Ru0 ọnụ ọgụgụ kasị elu nke RuNi sample gbanwere na ike njikọ dị ala na ọnụ ọgụgụ Ni0 na-atụgharị na ike njide dị elu tụnyere monometallic Ru na Ni., nke na-egosipụtakwa mbufe elektrọn site na Ni atom na ru atọm na RuNi SAA.Ihe nyocha nke Bader nke RuNi SAA (111) n'elu na-egosi na atom ndị dịpụrụ adịpụ na-ebu ebubo na-adịghị mma (Ruδ-) na-ebufe site na subsurface Ni atom (Mgbakwunye 24), nke kwekọrọ na nsonaazụ DRIFTS na ọnọdụ XPS.Iji mụọ usoro nhazi zuru oke nke Ru (Fig 4d), anyị mere mgbatị X-ray gbatịpụrụ spectroscopy nke ọma (EXAFS) na mgbanwe Fourier.Ihe nlele nwere RuNi 0.4 wt.%. (Ntinye mgbakwunye 5 na ihe mgbakwunye 25-28) na-egosi na ụzọ Ru-Ni nwere nọmba nhazi (CN) nke 5.4, ebe enweghị nhazi Ru-Ru na Ru-O na 0.4 wt.% RuNi sample.Nke a na-akwado na isi ru atọm na-atomically chụsasịrị na gburugburu Ni, akpụ a monoatomic alloy.Ekwesiri ighota na oke kachasi elu (~ 2.4 Å) nke nhazi Ru-Ru na-egosi na ihe omuma nke 0.6 wt.% RuNi ma kwalite ya na nlele site na 2 wt.% RuNi.Karịsịa, EXAFS curve dabara na-egosi na ọnụ ọgụgụ nhazi nke Ru-Ru mụbara nke ukwuu site na 0 (0.4 wt.% RuNi) ruo 2.2 (0.6 wt.% RuNi) wee gbasaa ruo 6.7 (2 wt.% .% RuNi), n'otu n'otu. , na-egosi na ka ibu Ru na-abawanye, ru atom na-eji nwayọọ nwayọọ na-agbakọta.A na-ejikwa K2-weighted wavelet mgbanwe (WT) nke akara ngosi Ru K-edge XAFS iji mụọ gburugburu nhazi nke ụdị Ru.Dị ka e gosiri na fig.4e, Ru foil lobes na 2.3 Å, 9.7 Å-1 na-ezo aka na onyinye Ru-Ru.N'ihe nlele nwere RuNi 0.4 wt.% (Fig. 4f) enweghị lobes na k = 9.7 Å-1 na 5.3 Å-1, ma e wezụga maka njikọ etiti nke Ru na Ru atom na O atọm (Fig 4g);A na-ahụ Ru-Ni na 2.1 Å, 7.1 Å-1, nke gosipụtara nguzobe SAA.Tụkwasị na nke ahụ, ihe ngosi EXAFS dị na K-n'akụkụ Ni maka ihe atụ dị iche iche egosighi ọdịiche dị ịrịba ama (Mgbakwunye 29), na-egosi na nhazi nhazi nke Ni bụ obere mmetụta nke elu Ru atom.Na nkenke, nsonaazụ nke AC-HAADF-STEM, na ọnọdụ CO-DRIFTS, na n'ime ọnọdụ XAFS gosipụtara nkwado nke ọma nke ruNi SAA catalysts na evolushọn nke ru irighiri ihe na Ni NP site na otu atom rue ru multimers site n'ịba ụba Ru ibu.Tụkwasị na nke ahụ, ihe oyiyi HAADF-STEM (Mgbakwunye 30) na EXAFS spectra (Mgbakwunye 31) nke RuNi SAA catalysts eji mee ihe gosiri na ọnọdụ mgbasa ozi na nhazi nhazi nke atom Ru adịghị agbanwe nke ọma mgbe usoro 5 gasịrị, na-egosi na ike RuNi SAA catalyst.
A na-eme nha H2-TPD iji mụọ mgbasa ozi dissociative nke hydrogen na ihe dị iche iche na-eme ka ọ pụta ìhè na ihe ndị a niile na-eme ka ndị a na-eme ka ha nwee ike H2 dị ike na-eme ka ọ dị elu na-eme ka ọ dị elu na ~ 100 Celsius C (Mgbakwunye 32).Nsonaazụ nke nyocha ọnụọgụ (Fig 33 nke mgbakwunye) egosighi njikọ doro anya n'etiti mmeghachi omume na ọnụọgụ nke hydrogen desorption.Tụkwasị na nke ahụ, anyị mere nnwale na D2 isotopes wee nweta mmetụta kinetic isotope (KIE) uru nke 1.31 (TOFH / TOFD) (Ntinye mgbakwunye 34), na-atụ aro na ịgbalite na dissociation nke H2 dị mkpa ma ọ bụghị usoro nkwụsị ọnụ.Emere ngụkọ DFT ka o wee nyochaa n'ihu n'omume mgbasa ozi na nkewa nke hydrogen na RuNi SAA vesos metallic Ni naanị (Mgbakwunye Fig. 35).Maka nlele RuNi SAA, ụmụ irighiri ihe H2 na-akacha mma chemisorb karịa otu atom Ru nwere ike mgbasa ozi nke -0.76 eV.N'ikpeazụ, hydrogen na-ekewa n'ime atọm H abụọ na-arụ ọrụ na saịtị ndị nwere oghere nke Ru-Ni RuNi SAA, na-emeri ihe mgbochi ike nke 0.02 eV.Na mgbakwunye na saịtị Ru, a nwekwara ike chemisorbed molecules H2 na saịtị elu nke Ni atom dị n'akụkụ Ru (ike mgbasa ozi: -0.38 eV) wee kewaa H abụọ na saịtị Ru-Ni na Ni-Ni oghere.Ihe mgbochi atọm 0.06 eV.N'ụzọ megidere nke ahụ, ihe mgbochi ike maka mgbasa ozi na nkesa nke mkpụrụ ndụ H2 n'elu Ni (111) bụ -0.40 eV na 0.09 eV, n'otu n'otu.Ihe mgbochi ike dị oke ala na ndịiche na-enweghị isi na-egosi na H2 na-ekewa ngwa ngwa n'elu Ni na RuNi surfactants (Ni-site ma ọ bụ Ru-site), nke na-abụghị isi ihe na-emetụta ọrụ catalytic ya.
Mgbasa ozi nke ụfọdụ otu na-arụ ọrụ dị oke mkpa maka ịhọrọ hydrogenation nke mkpụrụ.Ya mere, anyị mere mgbakọ DFT iji nyochaa nhazi nke 4-NS adsorption na saịtị ndị na-arụ ọrụ n'elu RuNi SAA (111), na nsonaazụ kachasị mma gosipụtara na Fig. 36e), nke N atọm dị na Ru-Ni oghere saịtị na abụọ O atọm na-njikọ na Ru-Ni interface na-egosi kasị ala adsorption ike larịị (-3.14 eV).Nke a na-egosi usoro mgbasa ozi nke temomenaịka dị mma karịa ma e jiri ya tụnyere nhazi kwụ ọtọ na ndị ọzọ yiri ya (Foto mgbakwunye. 36a-d).Tụkwasị na nke ahụ, mgbe mgbasa ozi nke 4-HC na RuNi SAA (111), ogologo nke njikọ N-O1 (L (N-O1)) na otu nitro mụbara ruo 1.330 Å (Fig 5a), nke dị ukwuu. ogologo karịa ogologo nke gaseous 4- NS (1.244 Å) (Mgbakwunye 37), ọbụna karịa L (N-O1) (1.315 Å) na Ni (111).Nke a na-egosi na mgbasa ozi N-O1 na-arụ ọrụ n'elu RuNi PAA na-abawanye nke ọma ma e jiri ya tụnyere nke mbụ Ni(111).
ihe nhazi mgbasa ozi nke 4-HC na Ni (111) na RuNi SAA (111) (Eads) n'elu (n'akụkụ na n'elu).Ru - violet, Ni - akwụkwọ ndụ akwụkwọ ndụ, C - oroma, O - uhie, N - acha anụnụ anụnụ, H - ọcha.b N'ime ọnọdụ FT-IR ụdị gaseous na chemisorbed 4-HC na monometallic surfactants Ni, Ru, RuNi (0.4 wt.%) na 2 wt.% RuNi, n'otu n'otu.c Normalized in situ XANES na d-phase-doziri Fourier EXAFS na Ru K-ọnụ nke 0.4 wt% RuNi PAA n'oge mgbasa ozi 4-NS (RuNi SAA-4NS) na usoro hydrogenation (RuNi SAA-4NS-H2) .Transformation spectra ;…e njupụta njupụta nke steeti (PDOS) nke elu mbụ nke RuNi SAA (111), N-O1 na gas 4-NS na 4-NS na-agbasa na RuNi SAA (111).“au” pụtara nkeji aka aka ike.
Iji nwalekwuo omume mgbasa ozi nke 4-NS, na ọnọdụ FT-IR, a na-eme nha na Ni monometallic, Ru monometallic, 0.4 wt% RuNi (SAA), na 2 wt% RuNi catalysts (Fig 5b).Ụdị FT-IR nke gaseous 4-NS gosipụtara ọnụ ọgụgụ njirimara atọ dị na 1603, 1528, na 1356 cm-1, nke e kenyere ν (C = C), νas (NO2), na νs (NO2) 46,47, 48.N'ihu monometallic Ni, a na-ahụ mgbanwe mgbanwe nke eriri atọ niile: v(C=C) (1595 cm–1), νas (NO2) (1520 cm–1), na νs (NO2) (1351 cm–1) ., nke na-egosi chemisorption nke C = C na -NO2 dị n'elu Ni elu (yikarịrị, na nhazi nke adsorption yiri).Maka ihe atụ nke monometallic Ru, redshifts nke band atọ ndị a (1591, 1514, na 1348 cm-1, n'otu n'otu) metụtara monometallic Ni, nke na-egosi mmụba dịtụ mma nke otu nitro na njikọ С=С na Ru.N'ihe dị ka 0,4 wt.%. Saịtị SAA.Tụkwasị na nke ahụ, n'adịghị ka ihe na-eme ka monometallic, ike nke νs (NO2) band (1347 cm-1) dị ike karịa νas (NO2) band (1512 cm-1) na 0.4 wt.% RuNi (SAA) ) , nke ejikọtara ya na nkwụsị nke NO bond na -NO2 iji mepụta nitroso intermediate dị ka nchọpụta gara aga49,50.A hụkwara ihe omume yiri nke ahụ na nlele ahụ nwere ọdịnaya RuNi nke 2 wt.%.Nsonaazụ ndị a dị n'elu kwadoro na mmetụta synergistic nke ebe bimetallic dị na PAA RuNi na-akwalite polarization na dissociation nke otu nitro, nke dị na nkwekọrịta dị mma na nhazi mgbasa ozi kachasị mma nwetara site na nchịkọta DFT.
N'ime ọnọdụ XAFS spectroscopy ka emere iji mụọ mgbanwe dị ike nke usoro eletrọnịkị na ọnọdụ nhazi nke RuNi SAA n'oge mgbasa ozi 4-NS na mmeghachi omume catalytic.Dị ka a pụrụ ịhụ site na K-edge XANES spectrum nke Ru (Fig 5c), mgbe mgbasa ozi nke 4-HC gasịrị, 0.4 wt.%.Tụkwasị na nke ahụ, akụkụ nke edoziri Fourier na-agbanwe EXAFS spectrum nke adsorbed 4-NS RuNi SAA (Fig 5d) na-egosi nkwalite doro anya nke akara na ~ 1.7 Å na ~ 3.2 Å, nke jikọtara ya na nhazi nke nhazi nke Ru-O.Ihe ngosi XANES na EXAFS nke 0.4 wt% RuNi SAA laghachiri n'ọnọdụ mbụ ha ka ịgbanye hydrogen gas nkeji iri atọ.Ihe omume ndị a na-egosi na a na-agbasa otu nitro na saịtị Ru site na njikọ Ru-O dabere na mmekọrịta elektrọnik.N'ihe gbasara XAFS ụdịdị Ni-K nsọtụ na ọnọdụ (Mgbakwunye Fig. 38), ọ dịghị mgbanwe doro anya a hụrụ, nke nwere ike ịbụ n'ihi mmetụta nke dilution nke Ni atom na nnukwu-adọ na elu Ni particles.Amụma njupụta nke steeti (PDOS) nke RuNi SAA (Fig 5e) na-egosi na ọnọdụ nitro otu dị n'elu ọkwa Femi na-agbasawanye ma na-aga n'okpuru ọkwa Femi na steeti adsorbed, nke na-egosikwa na electrons sitere na d- steeti RuNi SAA ngbanwe gaa na steeti a na-ejighị ya na -NO2.Ihe dị iche iche nke njupụta ụgwọ (Mgbakwunye 39) na nyocha Bader (Nkwupụta 40) na-egosi na njupụta electron agbakwunyere nke 4-NS na-agbakọta mgbe ọ gbasasịrị n'elu RuNi SAA (111).Na mgbakwunye, njupụta ụgwọ -NO2 abawanyela nke ukwuu ma e jiri ya tụnyere otu vinyl na 4-NS n'ihi nnyefe elektrọn na interface Ru-Ni, na-egosi ịgbalite kpọmkwem nke njikọ NO na otu nitro.
N'ebe a na-eme FT-IR iji nyochaa usoro catalytic nke mmeghachi omume hydrogenation nke 4-NS na ihe ndị na-emepụta ihe (Fig 6).Maka mmalite nickel catalyst (Fig 6a), ọ bụ naanị ntakịrị mbelata na njupụta nke nitro (1520 na 1351 cm-1) na C = C (1595 cm-1) ka a na-ahụ mgbe ọ na-agafe H2 maka 12 min. na-egosi na - Nrụ ọrụ NO2 na C=C adịghị ike.N'ihu monometallic Ru (Fig 6b), ν (C = C) band (na 1591 cm-1) na-agbada ngwa ngwa n'ime 0-12 min, ebe νs (NO2) na νas (NO2) na-ebelata ike. .Nke a na-egosi ngwa ngwa nke otu vinyl maka hydrogenation, na-eduga na nguzobe 4-nitroethylbenzene (4-NE).N'ihe dị ka 0,4 wt.%.A hụkwara otu egwu ọhụrụ gbadoro ụkwụ na 1629 cm-1, nke ekwuru na mgbada mkpọtụ nke NH.Na mgbakwunye, eriri maka ν (C = C) (1596 cm – 1) na-egosi naanị ntakịrị mbelata ka nkeji iri na abụọ gachara.Mgbanwe mgbanwe a na-akwado polarization na hydrogenation nke -NO2 ruo -NH2 site na 0.4 wt% RuNi (SAA) dabere na chemoselectivity pụrụ iche kwupụta 4-aminostyrene.Maka ihe atụ nke 2 wt.%. na 1348 cm-1).Nke a na-egosi na C = C na -NO2 na-arụ ọrụ nke ọma n'ihi ọnụnọ nke Ru-Ru na Ru-Ni interfacial centers, nke kwekọrọ na nhazi nke 4-NE na 4-AE na 2 wt.% RuNi catalyst.
N'ebe dị iche iche FT-IR nke 4-NS hydrogenation n'ihu monometallic Ni, b monometallic Ru, c 0.4 wt% RuNi SAA, na d 2 wt% RuNi na H2 na-asọ na 1700-1240 cm- Edekọkwara 1 dị ka mmeghachi omume gas mgbe 0, 3, 6, 9 na 12 nkeji, n'otu n'otu.“au” pụtara nkeji aka aka ike.Nkesa ike nwere ike yana ihe ndị dabara adaba maka C = C hydrogenation na NO scission n'ime 4-NS na e Ni(111) na f RuNi SAA(111) elu.Ru - violet, Ni - akwụkwọ ndụ akwụkwọ ndụ, C - oroma, O - uhie, N - acha anụnụ anụnụ, H - ọcha.“mgbasa ozi”, “IS”, “TS”, na “FS” na-anọchi anya steeti mgbasa ozi, steeti izizi, ọnọdụ mgbanwe, na steeti ikpeazụ, n'otu n'otu.
Ụzọ ndị nwere ike ime maka mgbanwe 4-NS na Ni (111) na RuNi SAA (111), gụnyere C = C hydrogenation na NO bond cleavage, bụ nyocha nke DFT iji mee ka ọ pụta ìhè ọrụ dị oke mkpa nke 4-NS.Akụkụ nke interface Ru-Ni maka mmepụta nke ebumnuche 4-AS.Maka Ni (111) elu (Fig 6e), ihe mgbochi ike maka NO scission na hydrogenation nke ìgwè vinyl na nke mbụ bụ 0.74 na 0.72 eV, nke na-egosi na chemoselective hydrogenation nke nitro dị iche iche na 4-HC bụ. adịghị mma.maka monometallic nickel n'elu.N'ụzọ megidere nke ahụ, ihe mgbochi ike maka NO dissociation bụ nanị 0.46 eV dị elu karịa nke RuNi SAA (111), nke dị ala karịa nke C = C bond hydrogenation (0.76 eV) (Fig 6f).Nke a na-akwado n'ụzọ doro anya na Ru-Ni interfacial centers na-ebelata ihe mgbochi ike maka NO scission na nitro otu, na-eduga na mbelata okpomọkụ nke nitro dị iche iche ma e jiri ya tụnyere C = C dị n'elu RuNi surfactant, nke kwadoro nsonaazụ nnwale.
A na-enyocha usoro mmeghachi omume na gbakọọ ume ike nke 4-NS hydrogenation na RuNi SAA dabere na nchịkọta DFT (Fig 7), na nhazi mgbasa ozi zuru ezu nke isi nzọụkwụ na-egosi na Fig. 41. Iji kwalite usoro mgbakọ na mwepụ. Ewepụrụ ihe mgbochi na-emepụta ike maka ụmụ irighiri mmiri na mgbako.efere ụdị9,17.Dị ka e gosiri na fig.7, molecules 4-NS na-ebu ụzọ banye n'otu n'otu na RuNi surfactant, ma abụọ O atọ dị na otu nitro na-ejikọta na Ru-Ni interfacial centers (S0; nzọụkwụ I).Mgbe nke ahụ gasịrị, emebiwo njikọ NO nke etinyere na saịtị Ru, nke jikọtara ya na nhazi nke nitroso intermediate (C8H7NO *) na saịtị interface Ru-Ni yana O * na saịtị Ni efu (S0 → S1 site na TS1; ike ike ihe mgbochi: 0.46 eV, nzọụkwụ nke abụọ).O* radicals bụ hydrogenated site na arụ ọrụ H atọm na-etolite H2O molekul na exotherm nke 0.99 eV (S1 → S2).Ihe mgbochi ike maka hydrogenation nke etiti C8H7NO* (Ngbakwunye 42 na 43) na-egosi na reactive H atọm sitere na saịtị Ru-Ni oghere na-akacha mma na-awakpo O atọm n'elu N atọm, na-ebute C8H7NOH* (S2 → S4; ike mgbochi TS2: 0.84 eV, nzọụkwụ III).Atọm N dị na C8H7NOH* wee bụrụ hydrogenated ka ọ bụrụ C8H7NHOH* ka ha gafechara ihe mgbochi 1.03 eV (S4→S6; nzọụkwụ IV), nke bụ nzọụkwụ na-akọwa mmeghachi omume niile.Na-esote, a gbajiri njikọ N-OH dị na C8H7NHOH * na interface Ru-Ni (S6 → S7; mgbochi ike: 0.59 eV; ogbo V), emesia OH * bụ hydrogenated na H O (S7 → S8; exotherm: 0.31 eV). ) Mgbe nke ahụ gasịrị, adọm N nke saịtị oghere Ru-Ni dị na C8H7NH * bụ nke ọzọ hydrogenated ka ọ bụrụ C8H7NH2 * (4-AS) nwere ihe mgbochi ike nke 0.69 eV (S8 → S10; nzọụkwụ VI).N'ikpeazụ, 4-AS na HO ụmụ irighiri ihe na-esi n'elu RuNi-PAA mebie, ihe na-eme ka ọ laghachiri na ọnọdụ mbụ ya (nzọụkwụ VII).Ọdịdị ihu ihu a pụrụ iche n'etiti otu ru atọm na Ni substrates, na-esonyere mmetụta synergistic nke ndị ọbịa doping na RuNi SAA, na-ebute ọrụ pụtara ìhè na chemoselectivity nke 4-NS hydrogenation.
Osikapa.4. Eserese atụmatụ nke usoro mmeghachi omume hydrogenation nke NS na 4-AS na elu RuNi PAA.Ru - violet, Ni - akwụkwọ ndụ akwụkwọ ndụ, C - oroma, O - uhie, N - acha anụnụ anụnụ, H - ọcha.Ihe ntinye na-egosi ikesa ike nke 4-NS hydrogenation na elu RuNi SAA (111), gbakọọ na ndabere nke DFT."S0" na-anọchi anya ọnọdụ mbụ, yana "S1-S10" na-anọchi anya usoro mgbasa ozi mgbasa ozi."TS" pụtara ọnọdụ mgbanwe.Ọnụọgụ ndị dị na brackets na-anọchi anya ihe mgbochi ike nke isi nzọụkwụ, na ọnụọgụ ndị fọdụrụ na-anọchi anya ike mgbasa ozi nke ndị etiti kwekọrọ.
Ya mere, a na-enweta ihe ndị na-eme ka RuNi SAA site na iji mmeghachi omume electrosubstitution n'etiti RuCl3 na Ni NP nwetara site na ndị na-ebu ụzọ LDH.E jiri ya tụnyere monometallic Ru, Ni na ndị ọzọ na-eme ka a na-emepụta ihe dị iche iche, nke RuNi SAA pụtara gosipụtara arụmọrụ catalytic dị elu maka 4-NS chemoselective hydrogenation (4-AS mkpụrụ:> 99%; uru TOF: 4293 h-1).Njirimara jikọtara gụnyere AC-HAADF-STEM, na situ CO-DRIFTS, na XAFS kwadoro na atoms Ru na-enweghị ike ime na Ni NP na ọkwa otu-atom site na njikọ Ru-Ni, nke na-ejikọta ya na nnyefe electron site na Ni ruo Ru.N'ọnọdụ XAFS, nnwale FT-IR, na ngụkọ DFT gosiri na saịtị interface Ru-Ni na-eje ozi dị ka saịtị na-arụ ọrụ n'ime ime maka ịgbalite NO bond na otu nitro;mmekọrịta dị n'etiti Ru na saịtị Ni gbara agbata obi na-eme ka ịgbalite etiti na hydrogenation aka, si otú a na-eme ka arụmọrụ catalytic dịkwuo mma.Ọrụ a na-enye nghọta na mmekọrịta dị n'etiti saịtị na-arụ ọrụ bifunctional na omume catalytic nke SAA na ọkwa atọm, na-emeghe ụzọ maka nhazi ezi uche nke ihe ndị ọzọ na-eme ka ụzọ abụọ dị iche iche na-ahọrọ nhọrọ.
Ejiri Sigma Aldrich zụta ihe nyocha nyocha ejiri mee nnwale ahụ: 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 na nitrostyrene.A na-eji mmiri dị ọcha mee ihe na nyocha niile.
Ahaziri NiAl LDH ndị hiererchical dị ka ihe mmalite site na uto ọnọdụ.Nke mbụ, urea (3.36 g), Al2 (SO4) 3 · 18H2O (9.33 g) na sodium tartrate (0.32 g) na-agbaze na mmiri deionized (140 ml).A na-ebufe ihe ngwọta na-esi na ya pụta na autoclave nke Teflon na-ekpuchi ma kpoo ọkụ na 170 ° C maka 3 h.A na-eji mmiri na-ekpo ọkụ na-asachapụ ihe na-esi na ya pụta ma kpochaa ya nke ọma, mgbe nke ahụ gasịrị, a na-agbanye ya na 500 ° C (2 ° C min-1; 4 h) iji nweta Al2O3 amorphous.Mgbe ahụ, Al2O3 (0.2 g), Ni (NO3) 2 6H2O (5.8 g) na NH4NO3 (9.6 g) gbasasịa na mmiri dị ọcha (200 ml) na pH gbanwere ~ 6.5 site na ịgbakwunye 1 mol l -1 amonia mmiri..Ebufere nkwusioru ahụ n'ime ite ma debe ya na 90 Celsius maka awa 48 iji nweta NiAl-LDH.Mgbe ahụ, NiAl-LDH ntụ ntụ (0.3 g) belatara na iyi H2 / N2 (10/90, v / v; 35 ml min-1) na 500 ° C maka 4 h (ọnụọgụ ọkụ: 2 ° C min -1). ).Nkwadebe nke ihe atụ nke nickel monometallic (Ni/Al2O3) etinyere na amorphous Al2O3.Ejiri usoro mbugharị eletrọnịkọ rụpụta ihe nlele bimetallic nke RuNi echekwara.Dị ka ọ na-adịkarị, a na-achụsasị ihe atụ ọhụrụ nke Ni / Al2O3 (0.2 g) na 30 ml nke mmiri dị ọcha, wee tinye ihe ngwọta nke RuCl3 (0.07 mmol l-1) nwayọọ nwayọọ ma kpalie ike maka nkeji 60 n'okpuru nchebe nke ikuku N2. .A na-ekpochapụ ihe na-esi na ya pụta, jiri mmiri dị ọcha saa ya, ma kpoo ya na oven dị ọkụ na 50 Celsius maka awa 24, na-enweta ihe nlele nwere 0.1% RuNi.Tupu nyocha nke catalytic, a na-ebu ụzọ belata ihe atụ ndị a emepụtapụtara ọhụrụ na ntinye H2 / N2 (10/90, v / v) na 300 ° C (ọnụọgụ ọkụ: 2 ° C min-1) maka 1 h, wee kpoo ọkụ. N2 Jụụ ruo ụlọ okpomọkụ.Maka ntụaka: ihe atụ nwere ọdịnaya Ru / Al2O3 nke 0.4% na 2% site na uka, yana ọdịnaya Ru nke 0.36% site na oke na 2.3% site na oke, a kwadebere ya site na mmiri ozuzo site na mmiri ozuzo na kpụ ọkụ n'ọnụ na 300 Celsius C (nri H2 / N2: 10/90, v / v, ọkụ ọkụ: 2 Celsius C min-1) maka awa 3.
Emere nnwale X-ray diffraction (XRD) na Bruker DAVINCI D8 ADVANCE diffractometer nwere isi iyi radieshon Cu Kα (40 kV na 40 mA).A na-eji Shimadzu ICPS-7500 Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) iji chọpụta n'ezie nnukwu ihe dị n'ụdị dị iche iche.E sere onyonyo eletrọnịkị (SEM) site na iji microscope eletrọn nke Zeiss Supra 55.Emere nnwale mgbasa ozi-desorption N2 na ngwaọrụ Micromeritics ASAP 2020 wee gbakọọ mpaghara elu dị iche iche site na iji usoro multipoint Brunauer-Emmett-Teller (BET).Emere njirimara nleba anya eletrọnịkị (TEM) na JEOL JEM-2010 igwe mkpirisi nnyefe dị elu.Nnukwu Angle Aberration Rected Scanning Transmission Electron Microscope Dark Field (AC-HAADF) - STEM nwere FEI Titan Cube Themis G2 300 nwere ihe ngbanwe aberration spherical na Energy Dispersive X-ray Spectroscopy (EDS) na JEOL JEM-ARM200F ngwá) na nha nke EDS .A tụrụ ọmarịcha ihe owuwu X-ray absorption spectroscopy (XAFS) na ọnọdụ K-ọnụ nke Ru na Ni K-ọnụ na ọwa 1W1B na 1W2B nke Beijing Synchrotron Radiation Facility (BSRF) nke Institute of High Energy Physics (IHEP), China. .Ụlọ akwụkwọ sayensị (KAN).A na-eme nnwale pulsed CO chemisorption na okpomọkụ-eme atụmatụ hydrogen desorption (H2-TPD) na ngwa Micromeritics Autochem II 2920 site na iji ihe nchọpụta thermal conductivity (TCD).Emere nnwale in situ DRIFTS na FT-IR na Bruker TENSOR II spectrometer infrared nke nwere cell mmeghachi omume gbanwere na ihe nchọpụta MCT nke ukwuu.A kọwara usoro nkọwa zuru ezu n'ime ozi mgbakwunye.
Nke mbụ, a na-etinye nke ọma na mkpụrụ (4-NS, 1 mmol), ihe mgbaze (ethanol, 8 ml) na catalyst (0.02 g) na 25 ml igwe anaghị agba nchara autoclave.Ejiri hydrogen 2.0 MPa (> 99.999%) sachaa ya kpamkpam, wee pịa ya ma mechie ya na 1.0 MPa na H2.Emere mmeghachi omume ahụ na 60 Celsius na ọsọ na-akpali akpali mgbe niile nke 700 rpm.Mgbe mmeghachi omume ahụ gasịrị, GC-MS na-achọpụta ngwaahịa ndị a na-emepụta ma nyochaa nke ọma site na iji Shimadzu GC-2014C gas chromatography system nke nwere kọlụm capillary GSBP-INOWAX (30 m × 0.25 mm × 0.25 mm) na onye nchọpụta FID.Achọpụtara ntụgharị 4-nitrostyrene na nhọrọ ngwaahịa dị ka ndị a:
A na-agbakọ ụkpụrụ ntụgharị (TOF) dị ka mol 4-NS gbanwere kwa saịtị igwe mol kwa elekere (mol4-NS mol-1 h-1) dabere na ntụgharị 4-NS dị ala (~ 15%).N'ihe banyere ọnụ ọgụgụ nke ọnụ ọnụ Ru-Ni, ọnụ ọgụgụ interface Ru-Ni na ọnụ ọgụgụ nke atom metal elu.Maka ule recyclability, a na-anakọta onye na-emepụta ihe site na centrifugation mgbe mmeghachi omume ahụ gasịrị, saa ya ugboro atọ na ethanol, wee webataghachi ya na autoclave maka usoro catalytic na-esote.
Emere ngụkọ niile density functional tiori (DFT) site na iji ngwugwu simulation Vienna ab initio (VASP 5.4.1).A na-eji ọrụ PBE Generalized Gradient Approximation (GGA) kọwaa mgbanwe elektrọn na ọnọdụ mmekọrịta.A na-eji usoro Projector Augmented Wave (PAW) kọwaa mmekọrịta dị n'etiti oghere atomic na electrons.Usoro Grimm DFT-D3 na-akọwa mmetụta nke mmekọrịta van der Waals n'etiti mkpụrụ na interface.Ngụkọta ihe mgbochi ike site na ịrị elu igwe na-agbanwe agbanwe nwere nkwalite onyonyo (CI-NEB) na ụzọ dimer.A na-eme nyocha ugboro ugboro nke oscillation, na-akwado ọnụnọ nke naanị otu ugboro n'echiche na ọnọdụ mgbanwe ọ bụla (Nkọwapụta 44-51).A kọwara ngụkọ zuru ezu na ozi ndị ọzọ.
A na-enye isi data nke na-akwado atụmatụ ndị dị n'isiokwu a na faịlụ data isi mmalite.Data ndị ọzọ metụtara ọmụmụ ihe a dị site n'aka ndị odee dị iche iche na arịrịọ ezi uche dị na ya.Edemede a na-enye data izizi.
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