Methanol-to-hydrocarbons(MTH)reaction comprises a set of crucial catalytic processes to produce light olefins,gasoline,or aromatics.MTH reaction is a classic example of reaction complexity in zeolite catalysis.The mol...Methanol-to-hydrocarbons(MTH)reaction comprises a set of crucial catalytic processes to produce light olefins,gasoline,or aromatics.MTH reaction is a classic example of reaction complexity in zeolite catalysis.The molecular understanding of reaction routes and deactivation mechanisms still encounters many challenges.Herein,we chose HZSM-22 zeolite with the simple one-dimensional 10-membered ring(10-MR)channel as a prototypical system,leveraging the spatial nanoconfinement effect of its unique pore architecture to minimize reaction complexity.The identification of the molecular structures of coke species with acene-,biphenyl-,or fluorene-typed structures was made possible through a combination of the advanced matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometry(MALDI FT-ICR MS)with the gas chromatography-mass spectrometer(GC-MS)technique.With this,we uncovered two modes of growth mechanism of coke molecules,i.e.,a stepwise route and a dehydrogenative coupling route.The findings deepen the mechanistic understanding of zeolite deactivation and provide a theoretical foundation for designing coke-resistant catalysts.展开更多
The combination of photo-and bio-catalysis in one-pot enables sustainable,visible-light driven cascade reactions for the synthesis of valueadded chiral chemicals under mild conditions.Despite the attractiveness of mer...The combination of photo-and bio-catalysis in one-pot enables sustainable,visible-light driven cascade reactions for the synthesis of valueadded chiral chemicals under mild conditions.Despite the attractiveness of merging the redox capability of heterogeneous photocatalysts with the excellent enantioselectivity of enzymes,developing such a reaction under one-pot conditions poses a challenge due to catalyst incompatibility.In this study,a cadmium sulfide(CdS)-enzyme composite was engineered for one-pot conversion of plastic-derived lactate into chiral compounds.By coating CdS onto alginate beads,its redox capability for the oxidation of lactate in water under visible light was preserved.The generated pyruvate subsequently underwent enantioselective transformation catalyzed by encapsulated enzymes within the beads,producing(R)-acetoin,L-alanine,or(R)-phenylacetylcarbinol.The core-shell structure of the CdS-enzyme composite protects the enzymes against radical attacks and facilitates recycling,yielding 81% of(R)-acetoin achieved after four reaction cycles.Additionally,we demonstrated an upcycling process converting post-consumer polylactic acid cups into(R)-acetoin.This work introduces a novel approach for integrating photocatalysts and enzymes to synthesize chiral chemicals from end-of-life plastics.展开更多
基金financially supported by the National Key R&D Program of China(2024YFB4105401)the National Natural Science Foundation of China(22372164,22288101 and 22072148)。
文摘Methanol-to-hydrocarbons(MTH)reaction comprises a set of crucial catalytic processes to produce light olefins,gasoline,or aromatics.MTH reaction is a classic example of reaction complexity in zeolite catalysis.The molecular understanding of reaction routes and deactivation mechanisms still encounters many challenges.Herein,we chose HZSM-22 zeolite with the simple one-dimensional 10-membered ring(10-MR)channel as a prototypical system,leveraging the spatial nanoconfinement effect of its unique pore architecture to minimize reaction complexity.The identification of the molecular structures of coke species with acene-,biphenyl-,or fluorene-typed structures was made possible through a combination of the advanced matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometry(MALDI FT-ICR MS)with the gas chromatography-mass spectrometer(GC-MS)technique.With this,we uncovered two modes of growth mechanism of coke molecules,i.e.,a stepwise route and a dehydrogenative coupling route.The findings deepen the mechanistic understanding of zeolite deactivation and provide a theoretical foundation for designing coke-resistant catalysts.
基金We thank MOE Tier-2 project(MOE-T2EP10221-0020)from Ministry of EducationSingapore and the National Research Foundation,Singapore,NRF Investigatorship(NRFI07-2021-0015)for the financial support.
文摘The combination of photo-and bio-catalysis in one-pot enables sustainable,visible-light driven cascade reactions for the synthesis of valueadded chiral chemicals under mild conditions.Despite the attractiveness of merging the redox capability of heterogeneous photocatalysts with the excellent enantioselectivity of enzymes,developing such a reaction under one-pot conditions poses a challenge due to catalyst incompatibility.In this study,a cadmium sulfide(CdS)-enzyme composite was engineered for one-pot conversion of plastic-derived lactate into chiral compounds.By coating CdS onto alginate beads,its redox capability for the oxidation of lactate in water under visible light was preserved.The generated pyruvate subsequently underwent enantioselective transformation catalyzed by encapsulated enzymes within the beads,producing(R)-acetoin,L-alanine,or(R)-phenylacetylcarbinol.The core-shell structure of the CdS-enzyme composite protects the enzymes against radical attacks and facilitates recycling,yielding 81% of(R)-acetoin achieved after four reaction cycles.Additionally,we demonstrated an upcycling process converting post-consumer polylactic acid cups into(R)-acetoin.This work introduces a novel approach for integrating photocatalysts and enzymes to synthesize chiral chemicals from end-of-life plastics.
