서강대학교

초록 (요약문)

In this study, photoelectrochemical (PEC) CO2 reduction reaction (CO2RR) has been comparatively studied to get the optimum parameters by using several hybrid composite cathodes based on pristine Cu-Sn bimetallic alloy with BiVO4 photoanode. Copper is already well known to reduce CO2 into hydrocarbons or oxygenates electrocatalytically. It also generates common products such as CO, HCOO-, and H2. Copper-based bimetallic electrocatalyst is considered to improve the activity and product selectivity of CO2RR. In the current work, we developed Cu-Sn nanoparticles (Cu-Sn NPs) by phase and structure engineering to get core-shell structure. Then, this Cu-Sn NPs were synthesized furthermore until obtained as surface coated catalyst on the surface of Cu foil as cathode for PEC CO2RR. Moreover, reduced graphene oxide (rGO) was coated on the surface of Cu/Cu-Sn/rGO layer to have sequential multi-electron shuttling function. After rGO coating, poly(4-vinylpyridine) (PVP) was also coated on the surface of Cu/Cu-Sn/rGO cathode to do CO2 adsorption and activation to decrease activation energy of rate determining first electron transfer and reduction reaction energy for CO2RR. Finally, Nafion (Naf) layer as proton conducting polymer was coated on the surface of Cu/Cu-Sn/rGO/PVP cathode to make one-pot reaction of proton-coupled sequential multi-electron transfer from rGO to CO2 reduction site. This work suggests the new creative strategy to fabricate multi-functional hybrid composite cathode for PEC CO2 reduction reaction to produce liquid solar fuels with high faradaic efficiency (FE) and solar-to-fuel (STF) performance.