Isolated cationic Pd species encapsulated in MFI zeolite,i.e.,Pd@MFI,have been successfully prepared via in situ hydrothermal route followed by oxidative treatment.The as-prepared Pd@MFI samples are investigated as pr...Isolated cationic Pd species encapsulated in MFI zeolite,i.e.,Pd@MFI,have been successfully prepared via in situ hydrothermal route followed by oxidative treatment.The as-prepared Pd@MFI samples are investigated as promising catalysts in the reaction of methane combustion.Typically,Pd@H-ZSM-5 shows remarkable activity in methane catalytic combustion with a low apparent activation energy value of 70.7 kj/mol as well as good catalytic stability even in excess water vapor.Detailed characterization results demonstrate the strong interaction between Pd sites and zeolite framework in Pd@ZSM-5 and the efficient stabilization of isolated Pd sites by zeolite thereof.Spectroscopy analyses reveal that the presence of BrΦnsted acid sites is beneficial to methane adsorption and its subsequent activation on adjacent Pd sites,constructing cooperation between Bronsted acid sites and Pd sites within the confined space of MFI zeolite toward high-efficiency methane catalytic combustion.The reaction mechanism of methane combustion catalyzed by Pd@H-ZSM-5 model catalyst is finally discussed.展开更多
The oxidative condensation between renewable furfural and fatty alcohols is a crucial avenue for producing high-quality liquid fuels and valuable furan derivatives.The selectivity control in this reaction process rema...The oxidative condensation between renewable furfural and fatty alcohols is a crucial avenue for producing high-quality liquid fuels and valuable furan derivatives.The selectivity control in this reaction process remains a significant challenge.Herein,we report the strategy of confining well dispersed gold species within ZSM-5 structure to construct highly active Au@ZSM-5 zeolite catalysts for the oxidative condensation of furfural.Characterization results and spectroscopy analyses demonstrate the efficient encapsulation of isolated and cationic Au clusters in zeolite structure.Au@ZSM-5(K)catalyst shows remarkable performance with 69.7%furfural conversion and 90.2%furan-2-acrolein selectivity as well as good recycle stability.It is revealed that the microstructure of ZSM-5 zeolite can significantly promote oxidative condensation activity through confinement effects.This work presents an explicit example of constructing zeolite encaged noble metal catalysts toward targeted chemical transformations.展开更多
Alkene hydroformylation is an extremely important industry process currently accomplished via homogeneous catalysis.Heterogeneous hydroformylation is being avidly pursued as a more economical and sustainable process.H...Alkene hydroformylation is an extremely important industry process currently accomplished via homogeneous catalysis.Heterogeneous hydroformylation is being avidly pursued as a more economical and sustainable process.Herein,we report the construction of zeolite-encaged rhodium catalyst for efficient hydroformylation.Through a facile in situ hydrothermal strategy,isolated Rh^(δ+)(δ=2.5)can be encaged in faujasite and efficiently stabilized via interaction with framework oxygen atoms,producing a Rh@Y model catalyst with well-defined rhodium sites and coordination environment.Rh@Y exhibits high catalytic activity,perfect chemoselectivity,and recyclability in 1-hexene hydroformylation under mild reaction conditions,making it a robust heterogeneous catalyst for potential applications.A state-of-the-art turnover frequency value of 6567 molC=C/molRh/h for Rh@Y can be achieved in 1-hexene hydroformylation at 393 K,outperforming all heterogeneous catalysts and most homogeneous catalysts under comparable conditions.With the well-defined structure of Rh@Y,the detailed mechanism of alkene hydroformylation can be interpreted via theoretical calculations,and the advantages of heterogeneous hydroformylation are well explained.This work provides a promising solution toward efficient heterogeneous noble metal catalysis by encaging stable isolated ions in a zeolite matrix.展开更多
文摘Isolated cationic Pd species encapsulated in MFI zeolite,i.e.,Pd@MFI,have been successfully prepared via in situ hydrothermal route followed by oxidative treatment.The as-prepared Pd@MFI samples are investigated as promising catalysts in the reaction of methane combustion.Typically,Pd@H-ZSM-5 shows remarkable activity in methane catalytic combustion with a low apparent activation energy value of 70.7 kj/mol as well as good catalytic stability even in excess water vapor.Detailed characterization results demonstrate the strong interaction between Pd sites and zeolite framework in Pd@ZSM-5 and the efficient stabilization of isolated Pd sites by zeolite thereof.Spectroscopy analyses reveal that the presence of BrΦnsted acid sites is beneficial to methane adsorption and its subsequent activation on adjacent Pd sites,constructing cooperation between Bronsted acid sites and Pd sites within the confined space of MFI zeolite toward high-efficiency methane catalytic combustion.The reaction mechanism of methane combustion catalyzed by Pd@H-ZSM-5 model catalyst is finally discussed.
基金supported by the National Natural Science Fund of China(Grant Nos.22025203 and 22121005).
文摘The oxidative condensation between renewable furfural and fatty alcohols is a crucial avenue for producing high-quality liquid fuels and valuable furan derivatives.The selectivity control in this reaction process remains a significant challenge.Herein,we report the strategy of confining well dispersed gold species within ZSM-5 structure to construct highly active Au@ZSM-5 zeolite catalysts for the oxidative condensation of furfural.Characterization results and spectroscopy analyses demonstrate the efficient encapsulation of isolated and cationic Au clusters in zeolite structure.Au@ZSM-5(K)catalyst shows remarkable performance with 69.7%furfural conversion and 90.2%furan-2-acrolein selectivity as well as good recycle stability.It is revealed that the microstructure of ZSM-5 zeolite can significantly promote oxidative condensation activity through confinement effects.This work presents an explicit example of constructing zeolite encaged noble metal catalysts toward targeted chemical transformations.
基金This work was supported by the National Natural Science Fund of China(grant nos.21872072 and 22025203)the Frontiers Science Center for New Organic Matter,Nankai University(grant no.63181206)Haihe Laboratory of Sustainable Chemical Transformations,Tianjin.
文摘Alkene hydroformylation is an extremely important industry process currently accomplished via homogeneous catalysis.Heterogeneous hydroformylation is being avidly pursued as a more economical and sustainable process.Herein,we report the construction of zeolite-encaged rhodium catalyst for efficient hydroformylation.Through a facile in situ hydrothermal strategy,isolated Rh^(δ+)(δ=2.5)can be encaged in faujasite and efficiently stabilized via interaction with framework oxygen atoms,producing a Rh@Y model catalyst with well-defined rhodium sites and coordination environment.Rh@Y exhibits high catalytic activity,perfect chemoselectivity,and recyclability in 1-hexene hydroformylation under mild reaction conditions,making it a robust heterogeneous catalyst for potential applications.A state-of-the-art turnover frequency value of 6567 molC=C/molRh/h for Rh@Y can be achieved in 1-hexene hydroformylation at 393 K,outperforming all heterogeneous catalysts and most homogeneous catalysts under comparable conditions.With the well-defined structure of Rh@Y,the detailed mechanism of alkene hydroformylation can be interpreted via theoretical calculations,and the advantages of heterogeneous hydroformylation are well explained.This work provides a promising solution toward efficient heterogeneous noble metal catalysis by encaging stable isolated ions in a zeolite matrix.
