The selective oxidation of toluene and its derivatives is extremely important in the chemical industry.The use of photocatalysis in organic synthesis has attracted considerable attention among synthetic chemists becau...The selective oxidation of toluene and its derivatives is extremely important in the chemical industry.The use of photocatalysis in organic synthesis has attracted considerable attention among synthetic chemists because of its ＂green＂ environmental characteristics.In this study,nanoscale Bi_2WO_6with a flower-like morphology was found to be a highly efficient photocatalyst in the catalytic oxidation of toluene and its derivatives using O_2 as the oxidant.The loading of Pd nanoparticles as a cocatalyst onto the flower-like Bi_2WO_6 was found to produce a significant enhancement in the catalytic activity.Mechanistic investigation showed that the superior performance of Pd/Bi_2WO_6 could be attributed to the improvement of both the reductive and oxidative abilities of Bi_2WO_6 by the loading of the cocatalyst.展开更多
Rubidium phosphate can be more conveniently obtained by extracting trace Rb+ from the salt lake brine. Rb_3PO_4 was found to be an excellent heterogeneous catalyst for transfer hydrogenation. Rb_3PO_4 lost 70% of its ...Rubidium phosphate can be more conveniently obtained by extracting trace Rb+ from the salt lake brine. Rb_3PO_4 was found to be an excellent heterogeneous catalyst for transfer hydrogenation. Rb_3PO_4 lost 70% of its active sites after adsorbing water, but the remaining was not affected. The reductions of aldehydes and ketones, when promoted by Rb_3PO_4, were allowed at room temperature. The activities of substrates at room temperature followed a descending order of 2,6-dichlorobenzaldehyde> 4-bromobenzaldehyde>benzaldehyde>acetophenone>anisaldehyde>butanone. A new catalytic cycle postulating a six-membered cyclic transition state for the reductions of aldehydes and ketones was proposed. These results exploited the catalytic usage of Rb_3PO_4 and worth in industrial application.展开更多
One of the central tasks in the field of heterogeneous catalysis is to establish structure‐function relationships for these catalysts,especially for precious metals dispersed on the sub‐nanometer scale.Here,we repor...One of the central tasks in the field of heterogeneous catalysis is to establish structure‐function relationships for these catalysts,especially for precious metals dispersed on the sub‐nanometer scale.Here,we report the preparation of MgAl2O4‐supported Pt nanoparticles,amorphous aggregates and single atoms,and evaluate their ability to catalyze the hydrogenation of benzaldehyde.The Pt species were characterized by N2adsorption,X‐ray diffraction(XRD),aberration‐corrected transmission electron microscopy(ACTEM),CO chemisorption and in situ Fourier transform infrared spectroscopy of the chemisorbed CO,as well as by inductively coupled plasma atomic emission spectroscopy.They existed as isolated or neighboring single atoms on the MgAl2O4support,and formed amorphous Pt aggregates and then nanocrystallites with increased Pt loading.On the MgAl2O4support,single Pt atoms were highly active in the selective catalytic hydrogenation of benzaldehyde to benzyl alcohol.The terrace atoms of the Pt particles were more active but less selective;this was presumably due to their ability to form bridged carbonyl adsorbates.The MgAl2O4‐supported single‐atom Pt catalyst is a novel catalyst with a high precious atom efficiency and excellent catalytic hydrogenation ability and selectivity.展开更多
基金supported by the National Natural Science Foundation of China(21322202,21472187)the National Basic Research Program of China(2010CB833300)~~
文摘The selective oxidation of toluene and its derivatives is extremely important in the chemical industry.The use of photocatalysis in organic synthesis has attracted considerable attention among synthetic chemists because of its ＂green＂ environmental characteristics.In this study,nanoscale Bi_2WO_6with a flower-like morphology was found to be a highly efficient photocatalyst in the catalytic oxidation of toluene and its derivatives using O_2 as the oxidant.The loading of Pd nanoparticles as a cocatalyst onto the flower-like Bi_2WO_6 was found to produce a significant enhancement in the catalytic activity.Mechanistic investigation showed that the superior performance of Pd/Bi_2WO_6 could be attributed to the improvement of both the reductive and oxidative abilities of Bi_2WO_6 by the loading of the cocatalyst.
基金Project(21576074)supported by the National Natural Science Foundation of China
文摘Rubidium phosphate can be more conveniently obtained by extracting trace Rb+ from the salt lake brine. Rb_3PO_4 was found to be an excellent heterogeneous catalyst for transfer hydrogenation. Rb_3PO_4 lost 70% of its active sites after adsorbing water, but the remaining was not affected. The reductions of aldehydes and ketones, when promoted by Rb_3PO_4, were allowed at room temperature. The activities of substrates at room temperature followed a descending order of 2,6-dichlorobenzaldehyde> 4-bromobenzaldehyde>benzaldehyde>acetophenone>anisaldehyde>butanone. A new catalytic cycle postulating a six-membered cyclic transition state for the reductions of aldehydes and ketones was proposed. These results exploited the catalytic usage of Rb_3PO_4 and worth in industrial application.
基金supported by the National Natural Science Foundation of China(21403213,21673226,21376236,U1462121)the"Hundred Talents Programme"of the Chinese Academy of Sciences+3 种基金the"Strategic Priority Research Program"of the Chinese Academy of Sciences(XDB17020100)National Key R&D Program of China(2016YFA0202801)Department of Science and Technology of Liaoning province under contract of 2015020086-101the Natural Science Foundation of Hunan Province(2016JJ2128)~~
文摘One of the central tasks in the field of heterogeneous catalysis is to establish structure‐function relationships for these catalysts,especially for precious metals dispersed on the sub‐nanometer scale.Here,we report the preparation of MgAl2O4‐supported Pt nanoparticles,amorphous aggregates and single atoms,and evaluate their ability to catalyze the hydrogenation of benzaldehyde.The Pt species were characterized by N2adsorption,X‐ray diffraction(XRD),aberration‐corrected transmission electron microscopy(ACTEM),CO chemisorption and in situ Fourier transform infrared spectroscopy of the chemisorbed CO,as well as by inductively coupled plasma atomic emission spectroscopy.They existed as isolated or neighboring single atoms on the MgAl2O4support,and formed amorphous Pt aggregates and then nanocrystallites with increased Pt loading.On the MgAl2O4support,single Pt atoms were highly active in the selective catalytic hydrogenation of benzaldehyde to benzyl alcohol.The terrace atoms of the Pt particles were more active but less selective;this was presumably due to their ability to form bridged carbonyl adsorbates.The MgAl2O4‐supported single‐atom Pt catalyst is a novel catalyst with a high precious atom efficiency and excellent catalytic hydrogenation ability and selectivity.
