Electrochemical $CO_2$ reduction using carbon-supported silver-palladium nanoalloy

Abstract

Electrochemical reduction of carbon dioxide to potential carbon sources has attracted a huge attention as an ideal reaction to reduce carbon dioxide and produce new energy resources. To enhance the electrochemical reduction, metal nanoparticles are one of the best catalysts due to their large surface area. Major challenges in this field are overcoming the large overpotential and controlling the selectivity among various products. One potential approach is using alloy nanoparticles, which change binding energies of intermediates on the catalyst surface and enhance the reaction kinetics for $CO_2$ reduction. In Chapter 1, the electrochemical $CO_2$ reduction reaction using metal catalyst, is introduced. Major products and thermodynamic reduction potentials of electrochemical $CO_2$ reduction are introduced. In Chapter 2, the reaction system for electrochemical $CO_2$ reduction with metal nanoparticles is demonstrated. Ag nanoparticles with the average diameter of 5 nm on carbon supports were used as a standard catalyst for this system. The catalyst, 5 nm Ag/C, was employed for the electrochemical $CO_2$ reduction. We confirmed that the catalytic efficiency of the 5 nm Ag/C was reproduced in the new system. In Chapter 3, new designed nanocatalyst are introduced to the electrochemical $CO_2$ reduction system. Silver-palladium nanoalloys having various ratios on carbon supports (AgPd/C) were synthesized through a one-pot method. The resulting AgPd/C was used as a catalyst for $CO_2$ reduction. The catalytic activity was highly dependent upon the catalyst composition. As a result, we successfully established reaction system for the accurate measurement of electrochemical $CO_2$ reduction. We synthesized the AgPd/C nanoalloy by the new one-pot method, and proposed the different insight of AgPd alloying effect for $CO_2$ electro-reduction.