Selenium doping to improve internal electric field for excellent photocatalytic efficiency of g-C3N4 nanosheets

Graphitic carbon nitride is a promising photocatalyst to address environmental issues and energy applications. Herein, we develop an efficient defect-containing functionalized system of 2D selenium doped g-C 3 N 4 porous nanosheets via one pot with two-step temperature for the first time. During heat treatment, Se-infused g-C 3 N 4 nanosheets loosen stacking and form thinner nanosheets , which could effectively shorten the electronic path of charge migration. The introduction of nitrogen vacancies creates a midgap energy state below the CB, which improves the light-harvesting efficiency. Moreover, the dual effect of N vacancy and Se doping provides a driving force for the dissociation of excitons and achieves an effective spatial charge separation. High specific surface area (104.1 m 2 /g), suitable bandgap (2.65 eV), and good photocurrent response (0.45 µA cm −2 ) help to enhance the photocatalytic efficiency of 1-SeCN remarkably. Henceforth, high photocatalytic H 2 production rate of 5441 µmol g −1  h −1 and CO evolution rate of 31.5 µmol g −1  h −1 verifies the effective Se doping enhances the photocatalytic efficiency of g-C 3 N 4 . Furthermore, DFT calculations are consistent with experimental results and this facile engineering strategy provides a scalable way to develop a novel, efficient g-C 3 N 4 -based photocatalyst for H 2 production and CO 2 reduction.