Hydrogenation of CO₂ to aromatics over In₂O₃-Co₃O₄/palygorskite-based HZSM-5 zeolite tandem catalyst

The silica-aluminum ratio and acidic site distribution of HZSM-5 were optimized by high-temperature treatment of palygorskite, and the In₂O₃-Co₃O₄/ palygorskite-based HZSM-5 zeolite tandem catalyst was developed for the highly efficient catalysis of CO₂ hydrogenation to aromatics. The tandem catalyst exhibited excellent catalytic performance, achieving a CO₂ conversion of 29.0 % and an aromatics selectivity of 61.3 % under reaction conditions of 320 °C, 3 MPa, and H₂/CO₂ = 3:1. In addition, no significant deactivation of the tandem catalyst was observed during the 120 h stability test. Characterization analysis revealed that oxygen vacancies in In₂O₃-Co₃O₄, together with In-Co species, enhanced CO₂ adsorption and activation, while the distinctive acidic site distribution of the palygorskite-based HZSM-5 zeolite promoted the aromatization reaction. The reaction mechanism of CO₂ hydrogenation to aromatics over the In₂O₃-Co₃O₄/ PAL-based HZSM-5 tandem catalyst follows a methanol-mediated pathway. This study proposes a viable catalyst design strategy for the efficient conversion of CO₂ and the sustainable synthesis of aromatics.