Highly selective conversion of CO₂ to lower hydrocarbons (C₂-C₄) over bifunctional catalysts composed of In₂O₃-ZrO₂ and zeolite

Although many researchers have reported CO₂ hydrogenation to various C1 chemicals, it is still challenging to directly and selectively convert CO₂ to C₂-C₄ hydrocarbons in terms of overcoming the extreme inertness of CO₂ and a high C-C coupling barrier. In the present work, we report an efficient integration of methanol-synthesis and the methanol-to-hydrocarbons with the bifunctional catalyst component of In₂O₃-ZrO₂ and SAPO-5. These tandem reactions exhibit an excellent relative selectivity of C₂-C₄ (83%) with a suppressed CH₄ relative selectivity less than 3% at T = 300 °C. A detailed analysis indicates that the partially reduced indium oxide surface (In₂O₃-ZrO₂) can better activate CO₂ and promote the synthesis of methanol than In₂O₃ alone, and C-C coupling is subsequently manipulated within the confined acidic pores of SAPO-5 according to XRD, H₂-TPR, CO₂-TPD, SEM and TEM. Furthermore, the proximity of two components and the content of Si also play an important role in such outstanding selectivity to C₂-C₄. Our study paves a new path for the direct synthesis of lower hydrocarbons.