Product Selectivity Change by Ag Nanoparticle Modification on Metal Cathode Electrodes for Electrochemical CO₂ Reduction

Electrochemical CO₂ reduction is an effective technique for reducing atmospheric CO₂ concentration, which is one of the causes of global warming. In addition, product control of CO₂ reduction is important for carbon capture and utilization (CCU). The products of CO₂ reduction are known to vary depending on the metal cathode material and the applied voltage. Thus, modification of metal cathode has been studied to control the kinds of products, including the single-crystal surfaces index, alloying with different metals, and the arrangement of multiple metals. In this study, Ag nanoparticle modifications on several kinds of metal surfaces were investigated.<br/>The Ag nanoparticles were sprayed on the electrode surface using a spray machine to modify the electrodes. The evaluations were performed by H-type cells with electrochemical cyclic voltammetry and chronopotentiometry. The reduced products were evaluated by gas chromatography. The surface condition of the electrode before and after the reaction was also evaluated.<br/>It was found that the metal cathode electrode modified with Ag nanoparticles improved the CO₂ reduction ability to CO compared with the bare metal electrode. The surface evaluation results showed that the surface showed dispersed Ag oxide nanoparticles on the metal surface, and it has the possibility of the improvement of CO₂ reduction.