Formation of C2 and C3 hydrocarbons through photocatalytic CO2 conversion on vertical Bi2WO6 nanosheets

Abstract

In contrast to conventional nanostructured photocatalysts that only catalyze the conversion of CO₂ into C1 compounds of CO and CH₃OH, in this study, the Bi₂WO₆ nanosheets are deliberately grown to form a unique vertical configuration for achieving superior photocatalytic CO₂ conversion in the production of additional C2/C3 hydrocarbons, such as HCOOCH₃, CH₃CHO, and CH₃COCH₃. These products can serve as high-caloric-value fuels and chemical feedstocks, contributing to sustainability by potentially replacing fossil fuels. The vertical Bi₂WO₆ nanosheets predominantly expose (010) crystal planes to the CO₂ atmosphere. By modifying the nanosheet to display a jagged porous feature that exposes a higher proportion of edge surfaces perpendicular to the main exposure faces, the resulting vertical porous Bi₂WO₆ nanosheets catalyze the formation of additional hydrocarbons, including CH₄ and CH₃CH₂CHO. This enhancement further strengthens the sustainability merit of this photocatalytic process. To support these experimental findings, density functional theory calculations verify the enhanced photocatalytic activity of a characteristic edge face, the Bi₂WO₆ (100) plane, compared to the Bi₂WO₆ (010) plane in the conversion of CO₂ and H₂O into hydrocarbons requiring multielectron transfer. This study highlights the effectiveness of the vertical Bi₂WO₆ nanosheets, primarily featuring exposed (010) crystal planes along with additional exposed edge faces, in promoting sustainable CO₂ conversion reactions for the production of C2/C3 hydrocarbons involving multielectron transfer processes.