Cu Nanoparticles Modified Step-Scheme Cu 2 O/WO 3 Heterojunction Nanoflakes for Visible-Light-Driven Conversion of CO 2 to CH 4 .

In this study, Cu and Cu 2 O hybrid nanoparticles were synthesized onto the WO 3 nanoflake film using a one-step electrodeposition method. The critical advance is the use of a heterojunction consisting of WO 3 flakes and Cu 2 O as an innovative stack design, thereby achieving excellent performance for CO 2 photoreduction with water vapor under visible light irradiation. Notably, with the modified Cu nanoparticles, the selectivity of CH 4 increased from nearly 0% to 96.7%, while that of CO fell down from 94.5% to 0%. The yields of CH 4 , H 2 and O 2 reached 2.43, 0.32 and 3.45 mmol/g cat after 24 h of visible light irradiation, respectively. The boosted photocatalytic performance primarily originated from effective charge-transfer in the heterojunction and acceleration of electron-proton transfer in the presence of Cu nanoparticles. The S-scheme charge transfer mode was further proposed by the in situ-XPS measurement. In this regard, the heterojunction construction showed great significance in the design of efficient catalysts for CO 2 photoreduction application.