Nickel Single Atoms Anchored on Ultrathin Carbon Nitride for Selective Hydrogen Peroxide Generation with Enhanced Photocatalytic Activity

Abstract

Photocatalysis technology provides a promising and effective method for hydrogen peroxide (H 2 O 2 ) production. Nevertheless, the photocatalytic H 2 O 2 production activity is greatly regulated by the two-electron oxygen reduction reaction ( 2eˉ O 2 RR ). Herein, we demonstrate a robust single atom photocatalyst (NiCN-x, Ni single atoms anchored on ultrathin g-C 3 N 4 ) for artificial H 2 O 2 production under visible light irradiation. A high H 2 O 2 generation rate of 27.11 mmol g -1 h -1 and an apparent quantum yield (AQY) of 8.56% at 400 nm are both obtained in the optimal NiCN-4 photocatalytic system. Based on DFT calculations, experimental results and advanced characterizations, we found that the high photocatalytic performance is attributed to the boosting 2eˉ O 2 RR process with the formation of Ni-μ-peroxide (Ni-OOH) and the unique electronic feature of Ni-Nx coordination sites. This study offers a new blueprint for the fabrication of single atom catalysts (SACs) to achieve artificial photosynthesis of H 2 O 2 under visible light irradiation.

Keywords: Photocatalysis, Selective H2O2 production, Two-electron transfer, Ni single atoms, Visible light