How carbon contamination on the photocatalysts interferes with the performance analysis of CO2 reduction

Abstract

Photocatalytic carbon dioxide (CO₂) reduction reaction (CO₂RR) for the production of valuable chemicals is a promising solar-driven strategy to mitigate CO₂ emissions. However, carbon contamination on the photocatalysts interferes with the investigation of CO₂RR performance. This work quantitatively investigates the significant impact of carbon contamination on performance analysis of photocatalytic CO₂RR, which can lead to false-positive results of photocatalysts with different types of band structure (i.e., TiO₂, CuO, and BiVO₄) due to photoinduced oxidation process. Moreover, the commonly used organic solvent in a laboratory environment (e.g., ethanol) was proved to have a profound impact on photocatalytic CO₂RR behaviour wherein 1 microliter of ethanol could boost the apparent methane generation by 17 times. To solve this issue, oxygen plasma treatment is demonstrated to be effective in removing surface carbon contamination. To minimise the impact of surface carbon contamination and eliminate false-positive results, it is expected to further enhance the photocatalytic performance and store catalysts in a carbon-free atmosphere.