[2P01-53] Poster Presentation

[2P20] Direct observation of proton donor in CO₂ photoreduction electrocatalyst by in-situ surface-enhanced Raman spectroscopy

*Tatsunosuke Manabe¹, Ryo Toyoshima¹, Hiroshi Kondoh¹ (1. Department of Chemistry, Keio University)

Electrochemical CO₂ reduction using photocatalysts has been attracting attention. Au/p-GaN catalyst, in which gold nanoparticles (AuNPs) are supported on p-type gallium nitride (p-GaN), are capable of CO₂ reduction using visible light due to the plasmon resonance of AuNPs. Meanwhile, the chemical stracture of proton donor required for CO₂ reduction with the Au/p-GaN catalyst is not clear. In this study, we attempted to observe proton donor using in-situ surface-enhanced Raman spectroscopy (in-situ SERS). The Au/p-GaN catalyst was prepared by vacuum evaporation. In-situ SERS measurement was performed in 0.5 M CO₂-saturated sodium bicarbonate solution with Au/p-GaN catalyst as a working electrode. SERS spectra showed that bicarbonate and carbonate replaced each other depending on the potential. This result suggests that bicarbonate act as proton donor during the CO₂ reduction.