Precise tuning of the properties of MOR-type zeolite nanoparticles to improve lower olefins selectivity in composite catalysts for CO₂ hydrogenation

CO2 utilization is a key technology for carbon neutrality and is in high demand worldwide; however, many challenges need to be overcome. Composite catalysts consisting of zirconia-based catalysts for CO2 hydrogenation and zeolite-based solid acid catalysts for methanol-to-olefins reaction have been realized one-pass synthesis of olefins from CO2. High selectivity for olefins is essential for utilizing this promising process, and in this work, we precisely tuned the properties of MOR-type zeolites using multiple-step post-synthetic treatments. Miniaturization by milling and recrystallization helped realize the optimization of the zeolite composition related to the acid strength as well as enhance gas diffusion. Defect-healing treatment recently developed by us was applied, and the defects generated in the framework during these processes were successfully removed. Finally, the optimized sample showed high catalytic activity in sequential CO2 hydrogenation to hydrocarbons with the olefin selectivity with an improvement in the olefin/paraffin ratio from 0.69 to 1.4.