The dehydrogenation of alkanes has emerged as a vital complementary process to address the increasing global demand for olefins.A key challenge remains in the construction of novel active centers that offer superior a...The dehydrogenation of alkanes has emerged as a vital complementary process to address the increasing global demand for olefins.A key challenge remains in the construction of novel active centers that offer superior activity,stability,and cost-effectiveness.Herein,tricoordinated cobalt atoms were successfully fabricated through an in-situ ligand-protected synthesis by introducing tungsten atoms into zeolite frameworks.These unsaturated Co species efficiently activate C-H bonds while suppressing C-C bond cleavage,resulting in exceptional catalytic activity and olefin selectivity in both propane and ethane dehydrogenation reactions.The optimized Co_(0.2%)@0.01W-S-1 catalyst demonstrated an impressive propylene formation rate of 15.2 molC_(3H6)gcC h^(-1)at 823 K and an ethylene formation rate of 240.3mol_(C2H4)g_(Co)^(-1)h^(-1)at 913 K,with propylene and ethylene selectivities of 99.0%and 97.5%,respectively.These results not only significantly surpass conventional tetracoordinated Co catalysts but also rival some Pt-based catalysts under similar conditions.Importantly,the catalyst exhibited excellent stability in dehydrogenation reactions,with no significant loss in catalytic activity after five consecutive regeneration cycles.This work offers valuable insights into the design of zeolite-supported non-precious metal catalysts with high activity and durability for efficient alkane dehydrogenation.展开更多
Palladium(Pd) has exceptional H_(2) adsorption capacity and has been used as an adsorptive filler in mixed matrix membranes(MMMs) to enhance H_(2) separation performance.However,a high Pd loading(20 wt%-60 wt%) is imp...Palladium(Pd) has exceptional H_(2) adsorption capacity and has been used as an adsorptive filler in mixed matrix membranes(MMMs) to enhance H_(2) separation performance.However,a high Pd loading(20 wt%-60 wt%) is impractical due to cost.In this study,highly dispersed Pd nanoclusters are confined within the channels of mesoporous silica nanoparticles(MSNs),largely improving Pd atom utilization for facilitating H_(2) transport while greatly reducing Pd loading content.MMMs prepared by mixing Pd@MSN with polybenzimidazole matrix,corresponding to a very low Pd loading of 0.6 wt%-3.0 wt%,exhibit much improved H_(2)/CO_(2) separation performance.Specifically,an MMM containing only 2.5 wt% Pd shows mixed-gas separation performance of302.6 barrer of H_(2) permeability and 16.3 of H_(2)/CO_(2) selectivity at 120 ℃,largely surpassing the latest 150 ℃ upper bound.Our work demonstrates the enormous potential for applying Pd-based MMMs in gas separation by reducing noble metal loading by nearly two orders of magnitude.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFA1506000)Gusu Innovation and Entrepreneurship Leading Talents Program(ZXL2022497)+5 种基金Jiangsu Distinguished Professor programfinancial support by National Natural Science Foundation of China(Grant No.22301057)Natural Science Foundation of Hebei Province(Grant No.B2023201065)Science Research Project of Hebei Education Department(Grant No.BJK2024103)supported by the Open Research Fund of Shanghai Key Laboratory of High-resolution Electron MicroscopyOpen Project of State Key Laboratory of Supramolecular Structure and Materials(sklssm2024019),ShanghaiTech University。
文摘The dehydrogenation of alkanes has emerged as a vital complementary process to address the increasing global demand for olefins.A key challenge remains in the construction of novel active centers that offer superior activity,stability,and cost-effectiveness.Herein,tricoordinated cobalt atoms were successfully fabricated through an in-situ ligand-protected synthesis by introducing tungsten atoms into zeolite frameworks.These unsaturated Co species efficiently activate C-H bonds while suppressing C-C bond cleavage,resulting in exceptional catalytic activity and olefin selectivity in both propane and ethane dehydrogenation reactions.The optimized Co_(0.2%)@0.01W-S-1 catalyst demonstrated an impressive propylene formation rate of 15.2 molC_(3H6)gcC h^(-1)at 823 K and an ethylene formation rate of 240.3mol_(C2H4)g_(Co)^(-1)h^(-1)at 913 K,with propylene and ethylene selectivities of 99.0%and 97.5%,respectively.These results not only significantly surpass conventional tetracoordinated Co catalysts but also rival some Pt-based catalysts under similar conditions.Importantly,the catalyst exhibited excellent stability in dehydrogenation reactions,with no significant loss in catalytic activity after five consecutive regeneration cycles.This work offers valuable insights into the design of zeolite-supported non-precious metal catalysts with high activity and durability for efficient alkane dehydrogenation.
基金supported by the National Natural Science Foundation of China (22378282,22472113,21988102,U23A20116)the Gusu Innovation and Entrepreneurship Leading Talent Plan (ZXL2023189)+2 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (23KJB150029)the Key Development Project of Jiangsu Province (BE2022056)the State Key Laboratory of Engines (SKLE),Tianjin University,for support。
文摘Palladium(Pd) has exceptional H_(2) adsorption capacity and has been used as an adsorptive filler in mixed matrix membranes(MMMs) to enhance H_(2) separation performance.However,a high Pd loading(20 wt%-60 wt%) is impractical due to cost.In this study,highly dispersed Pd nanoclusters are confined within the channels of mesoporous silica nanoparticles(MSNs),largely improving Pd atom utilization for facilitating H_(2) transport while greatly reducing Pd loading content.MMMs prepared by mixing Pd@MSN with polybenzimidazole matrix,corresponding to a very low Pd loading of 0.6 wt%-3.0 wt%,exhibit much improved H_(2)/CO_(2) separation performance.Specifically,an MMM containing only 2.5 wt% Pd shows mixed-gas separation performance of302.6 barrer of H_(2) permeability and 16.3 of H_(2)/CO_(2) selectivity at 120 ℃,largely surpassing the latest 150 ℃ upper bound.Our work demonstrates the enormous potential for applying Pd-based MMMs in gas separation by reducing noble metal loading by nearly two orders of magnitude.
