Mass Transfer Modulation by Hollow Multi-Shelled Structures for High Space-Time Yield Synthesis of Light Olefins from Syngas

The separation of CO activation and CC coupling enables oxide-zeolite catalyzed tandem reaction toward direct conversion of syngas into light olefins to be a promising alternative for the traditional Fischer-Tropsch process with elevated selectivity. Utilizing controlled mass transfer to match the activation of reactants and the coupling of intermediates presents an appealing strategy to break the limitation on space-time yield in this tandem process. In this work, ZnCrOx hollow multi-shelled structures (HoMS) are fabricated to enhance the adsorption and enrichment ability of syngas, thereby strengthening the rate-determining activation step of reactants and resulting in an accelerated generation of intermediates. When coupled with SAPO zeolite, quintuple-shelled ZnCrOx HoMS-based catalysts exhibit a record high C2 = -C4 = space-time yield of 559 mg center dot gcat-1 center dot h-1 with a selectivity of 90%. This work demonstrates the advantages of precise nanostructure sculpturing on the mass transfer behavior in the microenvironment and provides a new strategy for highly selective direct conversion of syngas to light olefins, based on efficient activation of reactants and sufficient feeding of intermediates through enrichment effects within HoMS. ZnCrOx hollow multi-shelled structures (HoMS) with enhanced adsorption and enrichment of syngas are fabricated to reinforce the rate-determining activation step of reactants, thus leading to an accelerated generation of intermediate. When coupled with SAPO zeolite, ZnCrOx HoMS based catalysts exhibit a record high C2 = -C4 = space-time yield of 559 mg center dot gcat-1 center dot h-1 with the selectivity of 90%. image