Extraordinary Promotion of Visible-Light Hydrogen Evolution for Graphitic Carbon Nitride by Introduction of Accumulated Electron Sites (BN2)

Abstract

The application of accumulated electron sites on the catalyst surface for photocatalytic hydrogen production represents a prospective strategy for efficient utilization of solar energy. Herein, the accumulated electron sites (BN2) loaded on graphitic carbon nitride (G-CN) were prepared without effort by a two-step calcination method in which melamine was calcined and then heat-treated with NaBH4. When compared with that of the bulk G-CN, the rate toward water splitting to produce H2 of the represented catalyst (CN-B0.05) greatly increased by 2.3 times under illumination (λ ≥ 420 nm). The improved activity could be attributed to the decrease in interlayer distance and the potential barrier of interlayers which was beneficial to readily transfer electrons in the Z direction, improve the adsorption and activation of water, and decline the Gibbs free energies for H* adsorption. The increase in π–π conjugation facilitated enhancement of the separation efficiency of photogenerated electron–hole pairs and light-capturing capabilities in the visible region with the introduction of BN2 sites. An approach for efficient H2 production is demonstrated in this work.