An efficient Cu-based catalyst for the hydrogenation of ethylene carbonate to ethylene glycol and methanol

Abstract

Indirect CO₂ conversion to ethylene glycol (EG) and methanol (ME) via CO₂-derived ethylene carbonate (EC) as the intermediate is an attractive and promising approach. Cu-Based catalysts have been regarded as effective catalysts for the hydrogenation of EC to yield ME and EG. In this work, we prepared Cu/SiO₂ catalysts through different methods for the hydrogenation of EC to yield ME and EG. The results show that Cu/SiO₂-AE catalysts prepared by an ammonia evaporation (AE) method are superior to Cu/SiO₂-DP catalysts prepared by a deposition–precipitation (DP) method. After modification using glucose with an optimal amount, the Cu₈G₁/SiO₂-AE catalysts showed enhanced catalytic performance, furnishing 86% selectivity to ME and 99% selectivity to EG at almost full conversion of EC, with a TOF value for ME formation reaching about 39 h⁻¹. A series of techniques such as N₂ sorption, ICP-AES, FT-IR, H₂-TPR, H₂-TPD, TEM, and XPS were adopted to characterize the physicochemical properties of relevant catalysts. It was found that the Cu/SiO₂-AE catalyst had a smaller Cu particle size. After modification with glucose, the Cu₈G₁/SiO₂-AE catalyst had the smallest Cu particle size, the highest hydrogen adsorption ability, and the strongest interaction of Cu with SiO₂ so that the highest Cu⁺/(Cu⁰ + Cu⁺) molar ratio was detected. In addition, upon investigation of catalyst stability and reusability, it was found that glucose modification for the Cu/SiO₂-AE catalyst can also alleviate the deactivation distinctly.