Exploring Spinel Oxides for CO₂ Hydrogenation in Tandem Reaction with SSZ-13 Catalyst

Abstract

Recent advancements in tandem reactions, specifically the single step of conversion of CO₂ to methanol and subsequent hydrocarbon synthesis from methanol (MTH), have attracted attention. This study presents such tandem reactions over various spinel oxides and SSZ-13 catalysts. The catalytic performance of 26 different spinel oxides was tested with SSZ-13 zeolite. Zn-based spinel oxide tandem catalysts (ZnAl₂O₄, ZnCr₂O₄, ZnFe₂O₄, ZnGa₂O₄) exhibited high hydrocarbon yields at 653 K and 1.0 MPa. Furthermore, amorphous Zn–Al–O and SSZ-13 tandem catalyst yielded 3.1 % of hydrocarbon while the tandem catalyst of spinel Zn–Al–O and SSZ-13 tandem catalyst yielded 7.2 %, indicating that the spinel structure is essential for the first step of the tandem reaction, methanol synthesis. ZnFe₂O₄ was found to have a high hydrocarbon yield per surface area in the tandem reaction at 653-673 K, more than 100 K higher than conventional methanol synthesis.