At present, the development of highly efficient electrocatalysts with more rational control of microstructures(e.g. particle size, morphology, surface structure, and electronic structure) and chemical composition is n...At present, the development of highly efficient electrocatalysts with more rational control of microstructures(e.g. particle size, morphology, surface structure, and electronic structure) and chemical composition is needed and remained great challenges. Transmission electron microscopy(TEM) can offer the information about the microstructures and chemical compositions of the electrocatalysts on nano and atomic scale, which enables us to establish the synthesis-structure-performance relationship and further direct the design of new electrocatalysts with high performance. In this minireview paper, a brief introduction on the basic characterization of electrocatalysts with TEM, followed by the studying of dynamic evolution of the electrocatalysts in electrochemical reactions with identical location-TEM, is discussed.展开更多
Selective hydrogenation of cinnamaldehyde(CAL)toward cinnamyl alcohol(COL)is an extremely important and challenging reaction.Herein,a series of Pt_(x)Fe_(y)-Al_(2)O_(3) bimetallic catalysts with varied Pt to Fe ratios...Selective hydrogenation of cinnamaldehyde(CAL)toward cinnamyl alcohol(COL)is an extremely important and challenging reaction.Herein,a series of Pt_(x)Fe_(y)-Al_(2)O_(3) bimetallic catalysts with varied Pt to Fe ratios were prepared by incipient wetness impregnation method.The introduction of Fe significantly modifies the electronic and surface properties of Pt,which clearly enhances the C=O hydrogenation selectivity.Among all the catalysts,Pt_(3)Fe-Al_(2)O_(3) displays the best catalytic performance and the conversion of CAL is 96.6%with 77.2%selectivity of COL within 1 h.In addition,Pt_(3)Fe-Al_(2)O_(3) had excellent reusability with 76%COL selectivity after five runs of the recycle process.Further characterization of the fresh,used and cycled catalysts revealed that the structure and electronic state of the synthesized Pt_(x)Fe_(y)-Al_(2)O_(3) are unchanged after hydrogenation reaction.The identical-location transmission electron microscopy(ILTEM)results revealed that the interaction between the nanoparticles and the supports was strong and the catalyst was relatively stable.展开更多
The palladium-catalyzed Suzuki-Miyaura cross-coupling(SMC)reaction has received worldwide attention as a powerful and convenient synthetic tool for the formation of biaryl compounds.However,these reactions are highly ...The palladium-catalyzed Suzuki-Miyaura cross-coupling(SMC)reaction has received worldwide attention as a powerful and convenient synthetic tool for the formation of biaryl compounds.However,these reactions are highly dependent on the activity and stable of catalysts.Herein,the support morphology-dependent catalytic performance of SMC reactions was investigated.The truncated hexagonal bipyramid(α-Fe_(2)O_(3)-O)and rod-shaped morphologies of alpha-Fe_(2)O_(3)(α-Fe_(2)O_(3)-R)were used as support to prepare PdCu nanoparticles(NPs)catalysts by NaBH_(4) reduction method.For PdCu/α-Fe_(2)O_(3)-R catalysts,the smaller size of PdCu NPs and more low coordination Pd sites leading to its superior catalytic performance for SMC reactions.Furthermore,it can be easily recycled through centrifugation and reused several times without obvious loss on its catalytic performance.Identical location transmission electron microscopy method was used to investigate the structural evolution of PdCu/α-Fe_(2)O_(3)-R catalysts.The results found that its structure almost unchanged during the catalytic reaction.展开更多
基金financial support provided by the National Natural Science Foundation of China (91545119, 21773269, 21703262)Youth Innovation Promotion Association CAS (2015152)+2 种基金the Joint Foundation of Liaoning Province National Science FoundationShenyang National Laboratory for Materials Science (2015021011)"Strategic Priority Research Program" of the Chinese Academy of Sciences (XDA09030103)
文摘At present, the development of highly efficient electrocatalysts with more rational control of microstructures(e.g. particle size, morphology, surface structure, and electronic structure) and chemical composition is needed and remained great challenges. Transmission electron microscopy(TEM) can offer the information about the microstructures and chemical compositions of the electrocatalysts on nano and atomic scale, which enables us to establish the synthesis-structure-performance relationship and further direct the design of new electrocatalysts with high performance. In this minireview paper, a brief introduction on the basic characterization of electrocatalysts with TEM, followed by the studying of dynamic evolution of the electrocatalysts in electrochemical reactions with identical location-TEM, is discussed.
基金the financial support provided by the National Natural Science Foundation of China(No.21773269,22072164,21761132025,51932005)LiaoNing Revitalization Talents Program(No.XLYC1807175)。
文摘Selective hydrogenation of cinnamaldehyde(CAL)toward cinnamyl alcohol(COL)is an extremely important and challenging reaction.Herein,a series of Pt_(x)Fe_(y)-Al_(2)O_(3) bimetallic catalysts with varied Pt to Fe ratios were prepared by incipient wetness impregnation method.The introduction of Fe significantly modifies the electronic and surface properties of Pt,which clearly enhances the C=O hydrogenation selectivity.Among all the catalysts,Pt_(3)Fe-Al_(2)O_(3) displays the best catalytic performance and the conversion of CAL is 96.6%with 77.2%selectivity of COL within 1 h.In addition,Pt_(3)Fe-Al_(2)O_(3) had excellent reusability with 76%COL selectivity after five runs of the recycle process.Further characterization of the fresh,used and cycled catalysts revealed that the structure and electronic state of the synthesized Pt_(x)Fe_(y)-Al_(2)O_(3) are unchanged after hydrogenation reaction.The identical-location transmission electron microscopy(ILTEM)results revealed that the interaction between the nanoparticles and the supports was strong and the catalyst was relatively stable.
基金financial support provided by the National Natural Science Foundation of China(grant No.22072164)the Research Fund of Shenyang National Laboratory for Materials Science.
文摘The palladium-catalyzed Suzuki-Miyaura cross-coupling(SMC)reaction has received worldwide attention as a powerful and convenient synthetic tool for the formation of biaryl compounds.However,these reactions are highly dependent on the activity and stable of catalysts.Herein,the support morphology-dependent catalytic performance of SMC reactions was investigated.The truncated hexagonal bipyramid(α-Fe_(2)O_(3)-O)and rod-shaped morphologies of alpha-Fe_(2)O_(3)(α-Fe_(2)O_(3)-R)were used as support to prepare PdCu nanoparticles(NPs)catalysts by NaBH_(4) reduction method.For PdCu/α-Fe_(2)O_(3)-R catalysts,the smaller size of PdCu NPs and more low coordination Pd sites leading to its superior catalytic performance for SMC reactions.Furthermore,it can be easily recycled through centrifugation and reused several times without obvious loss on its catalytic performance.Identical location transmission electron microscopy method was used to investigate the structural evolution of PdCu/α-Fe_(2)O_(3)-R catalysts.The results found that its structure almost unchanged during the catalytic reaction.
