Silver-modulated SiO2-supported copper catalysts for selective hydrogenation of dimethyl oxalate to ethylene glycol

• A SiO2-supported CuAg catalyst is prepared by a urea-assisted gelation method.
• Ag nanoclusters are involved in Cu nanoparticles on SiO2 surface.
• Ag modifies the copper dispersion and surface Cu+ site concentration.
• Hydrogenation of dimethyl oxalate to ethylene glycol over CuAg/SiO2 is enhanced.
• CuAg/SiO2 can retain the excellent activity for longer than 150 h.

We present the application of a one-step urea-assisted gelation method to prepare a SiO2-supported bimetallic catalyst composed of copper (Cu) and silver (Ag). Results show the remarkably enhanced performance of the catalyst for selective hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG). Coupled with a series of characterization and kinetic studies, the improved activity is attributed to the formation of Cu nanoparticles containing Ag nanoclusters on the SiO2 surface. The coherent interactions between the Cu and Ag species help create the active Cu+/Cu0 species in a suitable proportion and prevent the transmigration of bimetallic nanoparticles during the hydrogenation process. The optimized CuAg/SiO2 catalyst with an Ag/Cu atomic ratio of 0.05 has a balanced Cu+/Cu0 ratio and highly dispersed bimetal particles, which account for its high turnover frequency, EG selectivity of 97.0%, and excellent catalytic stability during the hydrogenation of DMO to EG for longer than 150 h.

A SiO2-supported bimetallic catalyst composed of Cu and a small amount of Ag shows remarkable enhancements in catalytic performance for the selective hydrogenation of dimethyl oxalate to ethylene glycol, which is essentially attributed to the formation of Cu nanoparticles containing Ag nanoclusters on SiO2 surface.Figure optionsDownload high-quality image (141 K)Download as PowerPoint slide