Stacking Engineering of Heterojunctions in Half-Metallic Carbon Nitride for Efficient CO2 Photoreduction

Enhancing charge separation in semiconductor photocatalysts is a major challenge for efficient artificial photosynthesis. Herein, a compact heterojunction is designed by embedding half-metallic C(CN)(3) (hm-CN) hydrothermally in BiOBr (BOB) as the backbone. The interface between hm-CN and BOB is seamless and formed by covalent bonding to facilitate the transmission of photoinduced electrons from BOB to hm-CN. The transient photocurrents and electrochemical impedance spectra reveal that the modified composite catalyst exhibits a larger electron transfer rate. The photocatalytic activity of hm-CN/BOB increases significantly as indicated by a CO yield that is about four times higher than that of individual components. Density-functional theory calculations verify that the heterojunction improves electron transport and decreases the reaction energy barrier, thus promoting the overall photocatalytic CO2 conversion efficiency. The half-metal nitride coupled semiconductor heterojunctions might have large potential in artificial photosynthesis and related applications.
Funding Agencies|National Natural Science Foundation of China; Major Program of National Natural Science Foundation of China [92248301]; Natural Science Foundation of Jiangsu Province [BK20220598]; Special Fund for Science and Technology Innovation of Jiangsu Province [BE2022610]; Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province [KFKT2022001]; Hong Kong Scholars Program [XJ2021021]; City University of Hong Kong Donation Research Grants [DON-RMG 9229021, 9220061]; City University of Hong Kong Strategic Research Grant [SRG 7005505]; [22308300]; [41977085]