Postsynthetically Tailoring Acid Properties and Pore Structures of ZnZrOx/MFI Catalysts for One-Pass CO2 Hydrogenation

This study investigated the performance of tandem catalysts, comprising a physical mixture of ZnZrO_x and MFI-type zeolites, in one-pass CO₂ hydrogenation. To finely adjust both the acidic properties and the pore structures, an alkali treatment was applied to a commercial zeolite. The alkali treatment resulted in enhanced catalytic activity and increased yields of C_2–4 olefin, C_2–4 paraffin, and C₅₊ hydrocarbon products, meanwhile suppressing coke formation and increasing the olefin to paraffin ratios. Comprehensive characterizations revealed that the development of the mesopore structure contributed to the observed enhancements in activity and hydrocarbon yields, with the decreased acid number rationalizing the increase in olefin to paraffin ratios. Reduced coke formation was attributed to both mesopore formation and increased external surfaces and optimized acid properties..