Synthesis of Mixed Oxides Through the Hydrolysis of Ionic Liquids and Assessment of Their Catalytic Activity in the Hydrogenation of CO2

Abstract

Mixed oxides, prepared through the hydrolysis of imidazolium ionic liquids (ILs), were investigated as potential catalysts for the hydrogenation of CO₂ to formate under mild reaction conditions. In this study, one-pot basic hydrolysis of two imidazolium ILs, [BMIm][MCl_x] (M = Zn, Ta, Ce, and Ti; x = 3–6), led to the formation of mixed oxides that, after calcination at 800–1000 °C, produced perovskite-like structures (ZnTa₂O₆/Zn₃Ta₂O₈, ZnTiO₃/Zn₂TiO₄, and CeTa₇O₁₉). The hydrogenation of CO₂ catalyzed by the mixed oxides in the presence of a base (DBU) at 80 °C and 20 bar (10 bar CO₂ and 10 bar H₂) gave up to 39 µmol of formate (6% yield) after 3 h of reaction.