Highly Efficient Tandem Electrosynthesis of Dimethyl Carbonate From CO₂

Current DMC production is energy-intensive, while generating CO₂ emissions. Electrosynthesis of DMC from CO₂ offers a sustainable alternative but faces challenges of inert CO₂ activation and unfavorable C-O coupling, leading to low selectivity and current density. Herein, we propose a tandem electrocatalysis strategy for efficient DMC production from CO₂ under ambient conditions, utilizing a cobalt polyphthalocyanine framework (CoPPc) with single-atom sites and atomically precise palladium-sulfur clusters (Pd₆S₁₂). The CoPPc-Pd₆S₁₂ tandem catalyst system synergistically activates CO₂ and enhances mass transport, elevating the local concentration of key intermediates (CO and methoxy species) for improving DMC production efficiency. Thus, the tandem system delivers exceptional performance with 93.4% DMC selectivity and 34.9 mmol L^-1 h^-1 production in 0.1 M NaBr methanol electrolyte, while achieving a recorded current density of 155.2 mA cm^-2 at 0.5 M electrolyte concentration. In situ generated CO and methoxy over CoPPc efficiently transfer to the Pd-S site, where achieves intermediate stabilization and optimal coupling orientation, boosting DMC selectivity and current density. Moreover, DFT calculations reveal that the CoPPc-Pd₆S₁₂ system reduces the energy barrier for C-O coupling, facilitating DMC formation. This work provides an efficient tandem electrocatalysis system for DMC production from CO₂ with high selectivity and large current density.