Constructing Built‐in Electric Field in Ultrathin Graphitic Carbon Nitride Nanosheets by N and O Codoping for Enhanced Photocatalytic Hydrogen Evolution Activity

作者：Bo Yan, Chun Tian Du, Guowei Yang · 发表于：Small · 年份：2019 · DOI：10.1002/smll.201905700 · 被引用次数：116 · 研究领域：Advanced Photocatalysis Techniques、Gas Sensing Nanomaterials and Sensors、Advanced Nanomaterials in Catalysis

Abstract Codoping of N and O in ultrathin graphitic carbon nitride (g‐C 3 N 4 ) nanosheets leads to an inner electric field. This field restrains the recombination of photogenerated carriers and, thus, enhances hydrogen evolution. The layered structure of codoped g‐C 3 N 4 nanosheets (N‐O‐CNNS) not only provides abundant sites of contact with the reaction medium, but also decreases the distance over which the photogenerated electron–hole pairs are transported to the reaction interface. Quantum confinement in the ultrathin structure results in an increased bandgap and makes the photocatalytic reaction more favorable than bulk g‐C 3 N 4 . Under visible light irradiation, N‐O‐CNNS with 3 wt% Pt achieves a hydrogen evolution rate of 9.2 mmol g −1 h −1 and a value of 46.9 mmol g −1 h −1 under AM1.5 with 5 wt% Pt. Thus, this work paves the way for designing efficient nanostructures with increased separation/transfer efficiency of photogenerated carriers and, hence, increased photocatalytic activities.