Efficient hydrogenation of ethylene carbonate derived from CO2 to synthesize methanol and ethylene glycol over core-shell Cu@GO catalyst

Abstract

The synthesis of sustainable methanol and ethylene glycol (EG) via hydrogenation of ethylene carbonate (EC) has caught researchers’ growing interests on account of the indirect chemical utilization of CO2. Core-shell Cu@GO catalysts with random nanoporous network of graphite oxide (GO) were synthesized via a simple method of ultrasonic precipitation. Cu@GO catalysts were analyzed systematically by N2 physisorption, TGA measurement, XRD, FT-IR, Raman, TEM, SEM, and XPS (XAES). In particular, the mentioned method was confirmed to be effective to fabricate the high dispersity core-shell Cu@GO catalysts through promoting the specific surface area. The as-prepared Cu@GO catalyst was then successfully applied in the hydrogenation of CO2-derived EC to produce methanol and EG. A high TOF of 1526 mgEC gcat-1 h-1 could be attained in EC hydrogenation at the reaction temperature of 493 K. Accordingly, the correlation of catalytic structure and performance disclosed that the synergistic effect between Cu+ and Cu0 was responsible for achieving high activity of the catalyst. In addition, the reusability of Cu@GO catalyst suggested that graphite oxide shell structure could decrease the aggregation of Cu particles, thus enhance the stability of Cu-based catalysts. DFT calculation results suggested that the involvement of carbon film on Cu was favorable for the stabilization of the active sites. This study is helpful for developing new and stable catalytic system for indirect chemical utilization of CO2 to synthesize commodity methanol and EG.