Exceptional CO₂ Hydrogenation to Gasoline Enabled by GaZrO_x/Ga-ZSM-5 Tandem Catalyst

CO₂ hydrogenation to gasoline offers a promising route for addressing energy challenges and enabling the effective utilization of carbon resources. However, the efficient conversion of CO₂ to gasoline remains a significant challenge due to insufficient hydrogen activation capacity on existing metal oxide/zeolite tandem catalysts, as well as low selectivity of gasoline among the reaction products. In this work, we develop a tandem catalytic system comprising GaZrO_x and Ga-substituted ZSM-5 (Ga-ZSM-5) that achieves high CO₂ conversion and high gasoline yield in CO₂ hydrogenation. The optimized tandem catalyst, GZO-700/Ga-Z5(50), achieves a CO₂ conversion of 17.2% with a C₅₊ selectivity of 83.2% at 320°C and 3 MPa, while maintaining low selectivities for CH₄ (< 1%) and CO (11.7%). The catalyst shows no significant deactivation over 400 h of continuous operation. By tuning the calcination temperature, the GaZrO_x component is optimized to exhibit appropriate Ga-H coverage and O-vacancy concentration, which synergistically promotes H₂ dissociation, H₂ migration, and CO₂ activation, leading to enhanced CO₂ conversion and gasoline production. Furthermore, the incorporation of Ga into the ZSM-5 framework in place of Al effectively reduces the acid strength and Brønsted/Lewis acid ratio while increasing the acid density, thereby significantly boosting the formation of C₅₊ hydrocarbons. The decrease in the acid strength of the catalyst also suppresses carbon deposition and, thus results in more than a twofold increase in the catalyst lifetime.