Effect of copper loading on texture, structure and catalytic performance of Cu/SiO2 catalyst for hydrogenation of dimethyl oxalate to ethylene glycol

Abstract

Cu/SiO₂ catalysts prepared by a convenient and efficient method using the urea hydrolysis deposition-precipitation (UHDP) technique have been proposed focusing on the effect of copper loading. The texture, structure and composition are systematically characterized by ICP, FT-IR, N₂-physisorption, N₂O chemisorption, TPR, XRD and XPS. The formation of copper phyllosilicate is observed in Cu/SiO₂ catalyst by adopting UHDP method, and the amount of copper phyllosilicate is related to copper loading. It is found the structure properties and catalytic performance is profoundly affected by the amount of copper phyllosilicate. The excellent catalytic activity is attributed to the synergetic effect between Cu⁰ and Cu⁺. DMO conversion and EG selectivity are determined by the amount of Cu⁰ and Cu⁺, respectively. The proper copper loading (30 wt%) provides with the highest ratio of Cu⁺/Cu⁰, giving rise to the highest EG yield of 95% under the reaction conditions of p = 2.0 MPa, T = 473 K, H₂/DMO = 80 and LHSV = 1.0 h⁻¹.