Assembly of ZnZrOx and ZSM-5 on hierarchically porous bio-derived SiO2 platform as bifunctional catalysts for CO2 hydrogenation to aromatics

Herein, we designed integrated ZnZrOx/ZSM-5 catalysts with adjustable intimacy of the two components for CO2 hydrogenation to aromatics. The rice husk derived-SiO2 (denoted as bio-SiO2) was employed as a platform to tune the intimacy, which can be adjusted by changing the amount of biomass during the catalyst fabrication. It was found that the optimization of intimacy significantly improved the aromatics selectivity from 28% to 74.7%. Importantly, the dimensionless number intimacy was quantified by considering the particle size, density, specific surface areas, and the limiting distance for methanol back-mixing. The intimacy acted as a descriptor governing the aromatics selectivity in the CO2 hydrogenation reaction, which boosted the transfer and conversion of intermediates from metallic sites to acidic sites. These findings shed light on the understanding of the intimacy criterion for boosting CO2 hydrogenation to aromatics with the controlled spatial distributions of the two components on a porous bio-platform.