Elevating Dimethyl Oxalate Hydrogenation Activity Over Core-Shell Cu/Sio2@Ceo2 Catalysts

Abstract

Increasing dimethyl oxalate (DMO) hydrogenation activity remains a challenge. A Cu catalyst was designed by creating Cu nanoparticles over SiO2 layer formed on the CeO2 particles (SiO2@CeO2) using the ammonia evaporation method followed by the calcination and reduction step. The optimized 30Cu/SiO2@5CeO2 catalyst shows good performance in the micro-packed bed reactor (100% DMO conversion, 95.9% ethylene glycol (EG) selectivity, 200 h stability) under the condition of the ratio of H2 to DMO (H2/DMO) = 30, 190 oC and 2 MPa in the run, and CeO2 was proved to be effective in the DMO hydrogenation process. The exposed CeO2 on the surface of catalyst was found to facilitate the formation of Cu+ by its interaction between adjacent Cu nanoparticles, resulting in the faster adsorption and dissociation of C=O bond on the catalyst surface, according to the characterization results obtained by the XRD, XPS and in situ FT-IR, etc.

Keywords: Dimethyl oxalate, Hydrogenation, Copper-based catalyst, CeO2, Micro-packed bed reactor