As a typical process-intensive strategy,a tandem reaction driven by a multifunctional catalyst is a paragon of the green catalytic process.Two or more active sites are usually required and their rational spatial distr...As a typical process-intensive strategy,a tandem reaction driven by a multifunctional catalyst is a paragon of the green catalytic process.Two or more active sites are usually required and their rational spatial distribution is critical for the multi-functional catalyst to act independently or synergistically.Here,we present a simple and stepwise method to construct a trifunctional integrated catalyst simultaneously with spatially intimate acidic(phosphotungstic acid(HPW)),basic(amino)and metal(Pd nanoparticles(NPs))sites in hierarchically porous UiO-66-NH_(2).Through fine controlling the ratio of immobilized HPW and amino groups,we can easily tune its accessible acidic and basic properties,and the anchored HPW molecules can be effectively used to mediate the catalytic performance of Pd NPs and further stabilize the Pd sites.This well-designed integrated catalyst showed excellent catalytic activity and yield(>97%)towards onepot three-step Deacetalization-Knoevenagel-Hydrogenation(D-K-H)catalysis reactions owing to the synergetic catalysis and the intimate spatial arrangement of the acid,basic and metal sites.More importantly,the trifunctional catalyst could be recycled at least five times without significantly losing its activity due to the strong interaction between the MOF and the vip molecules.This work provides some important insights into the construction of multifunctional integrated catalysts,especially for the application in challenging tandem catalysis.展开更多
基金supported by the National Natural Science Foundation of China(21706199,U1662134 and 51861135313)the National Key R&D Program of China(2017YFC1103800)the NRC(Nanostructure Research Centre),Wuhan University of Technology,Wuhan,430070,PR China.
文摘As a typical process-intensive strategy,a tandem reaction driven by a multifunctional catalyst is a paragon of the green catalytic process.Two or more active sites are usually required and their rational spatial distribution is critical for the multi-functional catalyst to act independently or synergistically.Here,we present a simple and stepwise method to construct a trifunctional integrated catalyst simultaneously with spatially intimate acidic(phosphotungstic acid(HPW)),basic(amino)and metal(Pd nanoparticles(NPs))sites in hierarchically porous UiO-66-NH_(2).Through fine controlling the ratio of immobilized HPW and amino groups,we can easily tune its accessible acidic and basic properties,and the anchored HPW molecules can be effectively used to mediate the catalytic performance of Pd NPs and further stabilize the Pd sites.This well-designed integrated catalyst showed excellent catalytic activity and yield(>97%)towards onepot three-step Deacetalization-Knoevenagel-Hydrogenation(D-K-H)catalysis reactions owing to the synergetic catalysis and the intimate spatial arrangement of the acid,basic and metal sites.More importantly,the trifunctional catalyst could be recycled at least five times without significantly losing its activity due to the strong interaction between the MOF and the vip molecules.This work provides some important insights into the construction of multifunctional integrated catalysts,especially for the application in challenging tandem catalysis.
