Constructing copper-zinc interface for selective hydrogenation of dimethyl oxalate

The development of robust catalysts for selective hydrogenation of dimethyl oxalate (DMO) is key for the expansion of ethylene glycol (EG) production from C1 and renewable feedstocks. Copper-based catalysts promoted with Cr are industrially used, but it is desirable to develop more environmentally-benign alternatives. Silica-supported copper-zinc bimetallic catalysts featuring intimate metal contact are designed and used to establish the structure-performance relationships through combining in-depth characterizations with steady-state catalytic testing. Our study highlights: i) that the surface Cu0/Cu+ ratio is a reliable catalytic descriptor that determines the activity and selectivity, and ii) the importance of copper-zinc interface in stabilizing copper nanoparticles both under reduction and hydrogenation conditions. Controlled zinc doping allows fine tuning of these properties for the targeted reaction. Excellent performance has been achieved on the best-performing catalyst with >99.6% DMO conversion, >96.0% EG selectivity, and unprecedented stability of 800 h without catalyst deactivation, which represents a significant advance in the selective hydrogenations.