Fabrication of Au catalysts for electrochemical reduction of CO₂ to syngas

In this study, we investigated the electrochemical conversion of CO₂ for producing syngas, which is a mixture of CO and H₂, using Au electrodes fabricated by physical vapor deposition (PVD Au), electrodeposition (ED Au), and the combination of the PVD and ED processes (PVD+ED Au). The PVD Au electrode effectively catalyzed the conversion of CO₂ into CO because of the good crystallinity and high coverage of Au on its surface; however, the electrochemically active surface area was relatively small, leading to low yields of syngas. In the case of the ED Au electrode, which had low crystallinity and a high surface area of Au, the selectivity for CO production was low and H₂ gas was produced as the primary product. The PVD+ED Au electrode had both high crystallinity and a large surface area of Au, resulting in the production of syngas composed of significant amounts of CO and H₂. This result suggests the suitability of PVD+ED Au as an efficient electrode for syngas production through the electrochemical reduction of CO₂.