Br-Mediated Pd Catalysis Promotes Intermediates Stabilization and Coupling for Anodic Electrosynthesis of Dimethyl Carbonate

Electrosynthesis of dimethyl carbonate (DMC) from methanol (MeOH) and CO on a Pd-based catalyst has shown high selectivity; however, most of the corresponding total current densities (j_total) are still too small to support industrial applications. In this study, we built a Pd-Br electrocatalytic system in a flow cell to produce DMC with both high selectivity and high reaction rate. Remarkably, up to 89.4% of the DMC Faradaic efficiency (FE_DMC) was achieved at j_total of 100 mA cm⁻². Mechanism studies suggest that the in situ generation of active sites with a proper distribution of Br-modified Pd(I) sites and PdBr₂ for the coadsorption of CO and MeOH is vital for this reactivity. Under Br mediation, the excessive formation of high-valence Pd species was inhibited, while the DMC formation was substantially facilitated in thermodynamic terms. These findings shed vital methodological and mechanistic insights for developing efficacious electrocatalytic systems for DMC synthesis.