Degrading volatile organic compounds at low temperatures and active sites aggregation are still challenging.In this study,a novel mesoporous zeolite silicalite-1(S-1–meso)enveloped Pt–Ni bimetallic catalysts(noted a...Degrading volatile organic compounds at low temperatures and active sites aggregation are still challenging.In this study,a novel mesoporous zeolite silicalite-1(S-1–meso)enveloped Pt–Ni bimetallic catalysts(noted as Pt1Ni1@S-1–meso)were synthesized via a facile in situ mesoporous template-free method.The Pt–Ni bimetallic nanoparticles were uniformly distributed and displayed a large specific surface area and enriched mesopores to facilitate the deep oxidation of toluene.The presence of the Pt–Ni O interface both increased the dispersion of the catalyst and improved its catalytic performance,thereby reducing the consumption of Pt.The Mars-van Krevelen mechanism and density function theory(DFT)calculations revealed that the Pt–Ni O interface effect changed the electronic structure of Pt and Ni species,reduced the activation potential for oxygen,formed reactive oxygen species,and facilitated the adsorption and activation of reactants in the direction favorable to the toluene oxidation.This study provides a guideline for minimizing the proportion of precious metals used in practical applications and a promising method for toluene elimination at low temperatures.展开更多
Highly dispersed and stable Pt-based catalysts play a crucial role in constructing efficient catalytic systems for alkane dehydrogenation.In this study,a novel bimetallic Pt-Sn catalyst confined in extra-large-pore EC...Highly dispersed and stable Pt-based catalysts play a crucial role in constructing efficient catalytic systems for alkane dehydrogenation.In this study,a novel bimetallic Pt-Sn catalyst confined in extra-large-pore ECNU-46 zeolite(denoted as Pt/Sn-ECNU-46)is prepared by post-treatment.The open-site framework Sn species((SiO)_(3)Sn-OH)serve as anchors to interact with Pt species,favoring the high dispersion of Pt.On the other hand,the framework Sn species act as the second metal to regulate the geometrical and electronic environment of Pt species,thus suppressing their accumulation.Pt/Sn-ECNU-46 achieves a good performance in propane dehy-drogenation(PDH)reaction with high initial propane conversion(46%)and propylene selectivity(>99%)as well as regeneration ability.In addition,Pt/Sn-ECNU-46 is also active in the dehydrogenation of n-hexane.This study explores the application of extra-large-pore zeolite as support in constructing metal-confined catalysts for alkane dehydrogenation.展开更多
In the methanol-to-hydrocarbons(MTH)process,C1 species,including methanol,dimethyl ether,and surface methoxy species(SMS),play crucial roles in the evolution of organic species and the construction of reaction network...In the methanol-to-hydrocarbons(MTH)process,C1 species,including methanol,dimethyl ether,and surface methoxy species(SMS),play crucial roles in the evolution of organic species and the construction of reaction networks.Understanding the roles of C1 species throughout the entire MTH process is both essential and challenging.Herein,the dynamic evolution of organic species and unique variation of C1 species during the real-time MTH process were observed by operando diffused reflectance Fourier transform infrared spectroscopy and ex-situ 13C cross polarization/magic-angle spinning nuclear magnetic resonance experiments.Importantly,density functional theory calculations thoroughly illustrated that methanol and SMS serve as key C1 species,in the form of not only methylation agents but also hydride acceptors,and their contributions vary across different reaction periods.Initially,SMS acts as the preferential C1 surface intermediate,methylating with hydrocarbons to propagate C–C bond,while also accepting hydrides to generate precursors for active hydrocarbon pool species.As reaction progresses,the role of SMS gradually diminishes,and thereby methanol becomes the predominant C1 species,in methylation for efficient product formation,meanwhile in hydride-transfer causing catalyst deactivation.Additionally,it was demonstrated that the confined zeolite microenvironment modified by large organics affects methanol adsorption and SMS formation,also accounting for the absence of SMS during the later period of reaction.This work provides a comprehensive and systematic understanding of the dynamic roles of C1 species throughout the MTH process,beyond the role as reactants.展开更多
As an important basic raw material,acetic acid has broad application prospects in industrial production[1].However,traditional synthetic methods for acetic acid mainly rely on fossil fuels[2].High-temperature and high...As an important basic raw material,acetic acid has broad application prospects in industrial production[1].However,traditional synthetic methods for acetic acid mainly rely on fossil fuels[2].High-temperature and high-pressure reaction processes not only lead to a serious energy crisis,but also sharpen the emission of greenhouse gases[3],which is not conducive to the effective implementation of sustainable development strategies.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22276086,21976078)the Natural Science Foundation of Jiangxi Province(Nos.20202ACB213001,20232BCJ22003)。
文摘Degrading volatile organic compounds at low temperatures and active sites aggregation are still challenging.In this study,a novel mesoporous zeolite silicalite-1(S-1–meso)enveloped Pt–Ni bimetallic catalysts(noted as Pt1Ni1@S-1–meso)were synthesized via a facile in situ mesoporous template-free method.The Pt–Ni bimetallic nanoparticles were uniformly distributed and displayed a large specific surface area and enriched mesopores to facilitate the deep oxidation of toluene.The presence of the Pt–Ni O interface both increased the dispersion of the catalyst and improved its catalytic performance,thereby reducing the consumption of Pt.The Mars-van Krevelen mechanism and density function theory(DFT)calculations revealed that the Pt–Ni O interface effect changed the electronic structure of Pt and Ni species,reduced the activation potential for oxygen,formed reactive oxygen species,and facilitated the adsorption and activation of reactants in the direction favorable to the toluene oxidation.This study provides a guideline for minimizing the proportion of precious metals used in practical applications and a promising method for toluene elimination at low temperatures.
基金supports from the National Natural Science Foundation of China(22222201)National Key R&D Program of China(2021YFA1501401,2023YFB3810602).
文摘Highly dispersed and stable Pt-based catalysts play a crucial role in constructing efficient catalytic systems for alkane dehydrogenation.In this study,a novel bimetallic Pt-Sn catalyst confined in extra-large-pore ECNU-46 zeolite(denoted as Pt/Sn-ECNU-46)is prepared by post-treatment.The open-site framework Sn species((SiO)_(3)Sn-OH)serve as anchors to interact with Pt species,favoring the high dispersion of Pt.On the other hand,the framework Sn species act as the second metal to regulate the geometrical and electronic environment of Pt species,thus suppressing their accumulation.Pt/Sn-ECNU-46 achieves a good performance in propane dehy-drogenation(PDH)reaction with high initial propane conversion(46%)and propylene selectivity(>99%)as well as regeneration ability.In addition,Pt/Sn-ECNU-46 is also active in the dehydrogenation of n-hexane.This study explores the application of extra-large-pore zeolite as support in constructing metal-confined catalysts for alkane dehydrogenation.
文摘In the methanol-to-hydrocarbons(MTH)process,C1 species,including methanol,dimethyl ether,and surface methoxy species(SMS),play crucial roles in the evolution of organic species and the construction of reaction networks.Understanding the roles of C1 species throughout the entire MTH process is both essential and challenging.Herein,the dynamic evolution of organic species and unique variation of C1 species during the real-time MTH process were observed by operando diffused reflectance Fourier transform infrared spectroscopy and ex-situ 13C cross polarization/magic-angle spinning nuclear magnetic resonance experiments.Importantly,density functional theory calculations thoroughly illustrated that methanol and SMS serve as key C1 species,in the form of not only methylation agents but also hydride acceptors,and their contributions vary across different reaction periods.Initially,SMS acts as the preferential C1 surface intermediate,methylating with hydrocarbons to propagate C–C bond,while also accepting hydrides to generate precursors for active hydrocarbon pool species.As reaction progresses,the role of SMS gradually diminishes,and thereby methanol becomes the predominant C1 species,in methylation for efficient product formation,meanwhile in hydride-transfer causing catalyst deactivation.Additionally,it was demonstrated that the confined zeolite microenvironment modified by large organics affects methanol adsorption and SMS formation,also accounting for the absence of SMS during the later period of reaction.This work provides a comprehensive and systematic understanding of the dynamic roles of C1 species throughout the MTH process,beyond the role as reactants.
基金financially supported by the Key Grant for Special Professors in Jiangsu Province(No.RK119STP23002)the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(No.NY223016)+2 种基金2024 Nanjing Science and Technology Innovation Program(No.NJKCZYZZ2024-06)the Project of State Key Laboratory of Organic Electronics and Information Displays,Nanjing University of Posts and Telecommunication(Nos.ZS030ZR24004 and ZS030ZR23034)the“Belt and Road”Innovation Cooperation Project of Jiangsu(No.BZ2022011).
文摘As an important basic raw material,acetic acid has broad application prospects in industrial production[1].However,traditional synthetic methods for acetic acid mainly rely on fossil fuels[2].High-temperature and high-pressure reaction processes not only lead to a serious energy crisis,but also sharpen the emission of greenhouse gases[3],which is not conducive to the effective implementation of sustainable development strategies.
