The determination of catalytically active sites is crucial for the design of efficient and stable catalysts toward desired reactions.However,the complexity of supported noble metal catalysts has led to controversy ove...The determination of catalytically active sites is crucial for the design of efficient and stable catalysts toward desired reactions.However,the complexity of supported noble metal catalysts has led to controversy over the locations of catalytically active sites(e.g.,metal,support,and metal/support interface).Here we develop a structurally controllable catalyst system(Pd/SBA-15)to reveal the catalytic active sites for the selective hydrogenation of ketones to alcohol using acetophenone hydrogenation as model reaction.Systematic investigations demonstrated that unsupported Pd nanocrystals have no catalytic activity for acetophenone hydrogenation.However,oxidized Pd species were catalytically highly active for acetophenone hydrogenation.The catalytic activity decreased with the decreased oxidation state of Pd.This work provides insights into the hydrogenation mechanism of ketones but also other unsaturated compounds containing polar bonds,e.g.,nitrobenzene,N-benzylidene-benzylamine,and carbon dioxide.展开更多
Atomically dispersed catalysts have demonstrated superior catalytic performance in many chemical transformations.However,limited success has been achieved in applying oxide-supported atomically dis-persed catalysts to...Atomically dispersed catalysts have demonstrated superior catalytic performance in many chemical transformations.However,limited success has been achieved in applying oxide-supported atomically dis-persed catalysts to semihydrogenation of alkynes under mild conditions.展开更多
Size effect plays a crucial role in catalytic hydrogenation.The highly dispersed ultrasmall clusters with a limited number of metal atoms are one candidate of the next generation catalysts that bridge the single-atom ...Size effect plays a crucial role in catalytic hydrogenation.The highly dispersed ultrasmall clusters with a limited number of metal atoms are one candidate of the next generation catalysts that bridge the single-atom metal catalysts and metal nanoparticles.However,for the unfavorable electronic property and their interaction with the substrates,they usually exhibit sluggish activity.Taking advantage of the small size,their catalytic property would be mediated by surface binding species.The combination of metal cluster coordination chemistry brings new opportunity.CO poisoning is notorious for Pt group metal catalysts as the strong adsorption of CO would block the active centers.In this work,we will demonstrate that CO could serve as a promoter for the catalytic hydrogenation when ultrasmall Pd clusters are employed.By means of DFT calculations,we show that Pd_(n)(n=2-147)clusters display sluggish activity for hydrogenation due to the too strong binding of hydrogen atom and reaction intermediates thereon,whereas introducing CO would reduce the binding energies of vicinal sites,thus enhancing the hydrogenation reaction.Experimentally,supported Pd_(2)CO catalysts are fabricated by depositing preestablished[Pd_(2)(μ-CO)_(2)Cl_(4)]2-clusters on oxides and demonstrated as an outstanding catalyst for the hydrogenation of styrene.The promoting effect of CO is further verified experimentally by removing and reintroducing a proper amount of CO on the Pd cluster catalysts.展开更多
基金supported by the National Natural Science Foundation of China(Nos.92261207,21890752,and 22002126)。
文摘The determination of catalytically active sites is crucial for the design of efficient and stable catalysts toward desired reactions.However,the complexity of supported noble metal catalysts has led to controversy over the locations of catalytically active sites(e.g.,metal,support,and metal/support interface).Here we develop a structurally controllable catalyst system(Pd/SBA-15)to reveal the catalytic active sites for the selective hydrogenation of ketones to alcohol using acetophenone hydrogenation as model reaction.Systematic investigations demonstrated that unsupported Pd nanocrystals have no catalytic activity for acetophenone hydrogenation.However,oxidized Pd species were catalytically highly active for acetophenone hydrogenation.The catalytic activity decreased with the decreased oxidation state of Pd.This work provides insights into the hydrogenation mechanism of ketones but also other unsaturated compounds containing polar bonds,e.g.,nitrobenzene,N-benzylidene-benzylamine,and carbon dioxide.
基金supported by the National Key R&D Program of China(2017YFA0207302)the National Natural Science Foundation of China(21890752,21731005,21573178,21773192,and 91845102)+3 种基金the Tencent Foundation through the XPLORER PRIZEChina Postdoctoral Science Foundation Project(2021T140394 and 2021M691877)the Young Scientists Fund of the National Natural Science Foundation of China(22202164).the funding from the Chemistry and Chemical Engineering Guangdong Laboratory(2211002 and 2111005)。
基金This work was supported by the National Key Research and Development Program of China(2017YFA0207302 and 2017YFA0207303)the National Natural Science Foundation of China(21890752,21731005,21420102001,21573178,and 91845102)the Fundamental Research Funds for Central Universities(20720180026).
文摘Atomically dispersed catalysts have demonstrated superior catalytic performance in many chemical transformations.However,limited success has been achieved in applying oxide-supported atomically dis-persed catalysts to semihydrogenation of alkynes under mild conditions.
基金the National Key R&D Program of China(2017YFA0207304 and 2017YFA0207303)the NNSF of China(21890752,21731005,21721001,21573178,and 91845102)the Fundamental Research Funds for the Central Universities(20720180026)for financial support。
文摘Size effect plays a crucial role in catalytic hydrogenation.The highly dispersed ultrasmall clusters with a limited number of metal atoms are one candidate of the next generation catalysts that bridge the single-atom metal catalysts and metal nanoparticles.However,for the unfavorable electronic property and their interaction with the substrates,they usually exhibit sluggish activity.Taking advantage of the small size,their catalytic property would be mediated by surface binding species.The combination of metal cluster coordination chemistry brings new opportunity.CO poisoning is notorious for Pt group metal catalysts as the strong adsorption of CO would block the active centers.In this work,we will demonstrate that CO could serve as a promoter for the catalytic hydrogenation when ultrasmall Pd clusters are employed.By means of DFT calculations,we show that Pd_(n)(n=2-147)clusters display sluggish activity for hydrogenation due to the too strong binding of hydrogen atom and reaction intermediates thereon,whereas introducing CO would reduce the binding energies of vicinal sites,thus enhancing the hydrogenation reaction.Experimentally,supported Pd_(2)CO catalysts are fabricated by depositing preestablished[Pd_(2)(μ-CO)_(2)Cl_(4)]2-clusters on oxides and demonstrated as an outstanding catalyst for the hydrogenation of styrene.The promoting effect of CO is further verified experimentally by removing and reintroducing a proper amount of CO on the Pd cluster catalysts.
