An electron-hole separation mechanism caused by the pseudo-gap formed at the interfacial Co-N bond between cobalt porphyrin metal organic framework and boron-doped g-C3N4 for boosting photocatalytic H2 production

Photocatalytic hydrogen evolution from water splitting presents an attractive prospect in dealing with the energy crisis, but the low efficiency of charge separation and migration still seriously hinders its fur-ther practical application. Here, an acidified boron-doped g-C3N4 (HBCNN) and cobalt porphyrin metal organic frameworks (CoPMOF) self-assembled two-dimensional and two-dimensional (2D/2D) hybrid photocatalyst is fabricated successfully. The resultant HBCNN/CoPMOF with optimum ratio exhibits a superior H-2 evolution rate of 33.17 mmol g(-1) h(-1), which is 3.04 and 100.50 times higher than the single HBCNN and CoPMOF, respectively. It is found that a coordination connection has formed between CoPMOF and HBCNN through Co-N bond, and the interfacial Co-N bond then forms a pseudo-gap in the up-spin channel of electronic states, establishing an electron-hole separation mechanism. It is this electron-hole separation mechanism that contributes to a Z-scheme transport mode of photogenerated carriers, which greatly promotes the photocatalytic H-2 production performance of HBCNN/CoPMOF heterostructure. This work may provide an idea for the design of heterojunction to improve the photo -catalytic performance by constructing electron-hole separation through interfacial bond. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

This study successfully fabricated a two-dimensional/two-dimensional hybrid photocatalyst composed of acidified boron-doped g-C3N4 and cobalt porphyrin metal organic frameworks (CoPMOF), which achieved electron-hole separation mechanism and improved the efficiency of photocatalytic hydrogen evolution.