Synergistic CeO2–HMOR bicomponent catalyst enables efficient coproduction of dimethyl carbonate and methyl formate via CO2–methanol coupling assisted by 1,1,1-trimethoxymethane hydrolysis

Abstract

The direct synthesis of dimethyl carbonate (DMC) from CO₂ represents a promising carbon-negative strategy for simultaneously producing high-value chemicals and mitigating greenhouse gas emissions. However, this approach faces fundamental challenges due to thermodynamic equilibrium limitations and the chemical inertness of CO₂. In this work, we developed a novel CeO₂–HMOR bicomponent catalyst that synergistically integrates nanorod-structured CeO₂ with HMOR zeolite. This catalytic system enables the efficient coproduction of DMC and methyl formate (MF) through CO₂–methanol coupling assisted by 1,1,1-trimethoxymethane (TMM) as a dehydration agent. Remarkably, the optimized CeO₂–HMOR catalyst achieves exceptional catalytic performance, with DMC and MF yields reaching 44.3% and 74.6%, respectively, and a DMC formation rate of 821.2 mmol g_CeO2⁻¹. Through combined in situ IR analysis and density functional theory (DFT) calculations, we reveal that the large pore size, strong acid sites, and enhanced hydrophilicity of HMOR synergistically promote TMM hydrolysis, accelerate the reaction of methyl carbonate with bridged methoxy species to produce DMC and H₂O, and suppress the formation of by-product dimethyl ether. This work not only demonstrates a breakthrough in CO₂-to-DMC conversion efficiency but also establishes a generalizable catalyst design principle for overcoming thermodynamic limitations in CO₂ utilization via acid–base cooperative catalysis.