Metal-free boron doped g-C3N5 catalyst: Efficient doping regulatory strategy for photocatalytic water splitting

As a promising strategy for addressing the energy shortage, photocatalytic overall water splitting (POWS) is usually restricted by two fatal drawbacks of photocatalyst: the conflict between high utilization of solar and strong redox ability of photogenerated electrons and holes; and the fast recombination of charge carriers. Herein, we introduce the single boron atom into g-C3N5 by the density functional theory simulation to overcome the abovementioned dilemma and obtain a suitable catalyst for POWS. Based on the effective mass theory (EMT), we regulate the levels of impurity states by adjusting the doping site. Two doping types from 18 doping models are screened out to meet the needs of POWS. On the one hand, the suitable impurity levels induced by skillfully designed boron doping not only extend the light absorption range from ultraviolet to visible light region, but also ensure the driving force of photogenerated electrons and holes for overall water splitting. On the other hand, the impurity states effectively separate the photogenerated electrons and holes spatially. This can suppress the recombination of photogenerated carriers. Our research not only provides a promising photocatalyst for POWS, but also advances the development of the doping strategy.