A Water-Soluble Sodium Pectate Complex with Copper as an Electrochemical Catalyst for Carbon Dioxide Reduction

A selective noble-metal-free molecular catalyst has emerged as a fruitful approach in the quest for designing efficient and stable catalytic materials for CO(2) reduction. In this work, we report that a sodium pectate complex of copper (PG-NaCu) proved to be highly active in the electrocatalytic conversion of CO(2) to CH(4) in water. Stability and selectivity of conversion of CO(2) to CH(4) as a product at a glassy carbon electrode were discovered. The copper complex PG-NaCu was synthesized and characterized by physicochemical methods. The electrochemical CO(2) reduction reaction (CO(2)RR) proceeds at −1.5 V vs. Ag/AgCl at ~10 mA/cm(2) current densities in the presence of the catalyst. The current density decreases by less than 20% within 12 h of electrolysis (the main decrease occurs in the first 3 h of electrolysis in the presence of CO(2)). This copper pectate complex (PG-NaCu) combines the advantages of heterogeneous and homogeneous catalysts, the stability of heterogeneous solid materials and the performance (high activity and selectivity) of molecular catalysts.