Low-temperature CO₂ hydrogenation to aromatics over ZnZrO_x integrated with boron-modified ZSM-5

Direct CO₂ hydrogenation to value-added aromatics has attracted considerable attention in recent years. Nevertheless, designing highly efficient and highly stable catalysts for low-temperature CO₂ hydrogenation to aromatics remains a significant challenge. Herein, boron-modified ZSM-5 zeolites with a stacked lamellar morphology are synthesized through a simple one-step solid-state crystallization method, and are subsequently integrated with ZnZrO_x to obtain a highly active bifunctional catalyst for CO₂ hydrogenation to aromatics. B incorporation is found to effectively tune the framework Al placement and to increase the proportion of Al species in the intersection channels, which are beneficial to the formation of aromatics. In addition, B modification also increases the number of Brønsted acid sites and weakens the acid strength of zeolite. The synergy of Al distribution, acidity and morphology promotes the facile formation and diffusion of aromatics in the bifunctional catalysts, significantly improving the aromatic selectivity and stability. Under the mild reaction conditions of 300 ºC and 3 MPa, the ZnZrO_x/B-modified ZSM-5 catalyst enables an unprecedented performance with an aromatic selectivity of 88.0 % at a CO₂ conversion of 14.3 %. Among them, > 99 % are C₈–C₁₀ aromatics, which are important precursors for producing kerosene-based aviation fuels. Notably, the as-synthesized bifunctional catalyst exhibits an ultra-high stability of over 1000 h. In situ DRIFTS analysis indicates that oxygen-containing species and light olefins are the key intermediates in the CO₂ hydrogenation to aromatics reaction. This work offers a promising new route and a highly efficient bifunctional catalyst system for the low-temperature CO₂ hydrogenation into aromatics.