Tetragonal zirconia based ternary ZnO-ZrO2-MOx solid solution catalysts for highly selective conversion of CO2 to methanol at High reaction temperature.

• Co-precipitation is verified optimal for synthesis of ZnO-ZrO 2 solid solution catalyst. • T-ZrO 2 is retained with lattice defects after metal doping, contributing to improved property. • Mg-doped catalyst presents considerable methanol selectivity even at mild reaction condition. Catalytic conversion of CO 2 to methanol has attracted increasing interests as a promising strategy for reducing excessive CO 2 emissions. However, the methanol selectivity drops rapidly with elevated temperature due to enhanced CO synthesis using conventional catalysts, which hiders its application. Herein, ZnO-ZrO 2 solid solution catalysts (SSCs) were prepared with different methods and modified by adding extra metal, i.e., Al, Cr, Fe or Mg. As-prepared SSCs were characterized and tested in reaction. The results show that prepared ZnO-ZrO 2 SSCs possess similar chemical compositions but different crystals, morphologies and pore systems, among which the C-ZZ synthesized by co-precipitation exhibits the optimal property. After doping, the basic crystal of tetragonal ZrO 2 can be retained and ternary ZnO-ZrO 2 -MO x SSCs are successfully prepared. There come dramatic improvements in overall catalytic performance. Specifically, the 3Mg-C-ZZ SSC, at 3.0 MPa and GHSV of ˜2000 h⁻¹, maintains a considerable methanol selectivity of 81.5 % even at 320 °C. Prepared catalysts present remarkable superiorities to conventional copper-based catalysts especially at high reaction temperatures, which endures them promising applications in coupling conversion of CO 2 to valuable chemicals with the intermedia of methanol. [ABSTRACT FROM AUTHOR]