Enhancement of light olefin production in CO2 hydrogenation over In2O3-based oxide and SAPO-34 composite

Indium-based oxides are potential catalysts for CO2 hydrogenation to methanol. However, upon complexing with SAPO-34, they give a C2=–C4= yield below 7.3% due to production of large amounts of CO and CH4 at high CO2 conversion. Therefore, a large improvement of the C2=–C4= yield over indium-based oxide and zeolite composites is a challenge. In this context, InCeOx and InCrOx oxides were prepared and found to produce more methanol than In2O3 or In–Zr oxide. Experimental and DFT calculation results reveal that incorporation of Ce or Cr into In2O3 generates more surface oxygen vacancies and enhances the electronic interaction between HCOO* intermediates and the catalyst surface, which decreases HCOO* and CH3OH formation free energy barriers and enthalpy barriers. Compared with InCeOx(0.13) and In2O3, InCrOx(0.13) shows higher catalytic activity for CO2 hydrogenation, and by coupling with SAPO-34, it gives a C2=–C4= yield of 1.5–2.0 times those obtained on In2O3/SAPO-34 and In-Zr/SAPO-34 at CO2 conversion of 33.6%.