Electrosynthesis of diphenyl carbonate catalyzed by Pd2+/0 (in situ NHC) redox catalyst promoted at Au anode

The effects of Au anodes on electrochemical carbonylation of phenol with CO (1 atm) to diphenyl carbonate (DPC) catalyzed by Pd (in situ NHC) electrocatalyst were studied under galvanostatic electrolysis conditions. Au supported on carbon materials (Au/carbon) were effective anodes for oxidation of the homogeneous Pd electrocatalyst. Various carbon materials, Vulcan XC-72 carbon black (XC72), activate carbon, Ketjenblack, and graphene nanoplatelets (graphene-1, -2, -3) were tested as a support for Au. The Au/graphene-3 was the most effective anode for DPC formation. Effects of Au loadings and reducing agents (H-2 and NaBH4) on the reactivity of the Au/graphene-3 anode for the DPC formation were studied and the materials were characterized using XRD spectroscopy and TEM analysis. These experimental facts indicated that small Au particles on the surface of graphene were superior for the DPC synthesis by the Pd (in situ NHC) electrocatalyst.