Coupling P Nanostructures with P‑Doped g‑C₃N₄ As Efficient Visible Light Photocatalysts for H₂ Evolution and RhB Degradation

Fabricating heterostructures to promote the charge separation and doping heteroatom to modulate the band gap of the photocatalysts have been regarded as effective strategies to improve the photocatalytic performance. However, it is still an unresolved issue of doping element and fabricating heterostructures with good contact at the same time. In this study, P nanostructures/P doped graphitic carbon nitride composites (P@P-<i>g</i>-C₃N₄) were successfully composited by a solid reaction route. Various structural characterizations, including X-ray adsorption near edge structure, indicate that P has been doped into g-C₃N₄ and P nanostructures were directly grown on g-C₃N₄ to form heterostructures. As expected, the intimate contacted heterostructured composites exhibit much enhanced light absorption and high-efficiency transfer and separation of photogenerated electron–hole pairs, and consequently, the composites also possess the superior photocatalytic performance in the rapidly degrading RhB and an efficient H₂ production rate of 941.80 μmolh^–1g^–1. Systematical studies combining experimental measurements with theoretical calculations were carried out to expound the underlying reasons behind the distinct performance. This study pave a one-step way to synthesize earth abundant element C, N, and P as novel photocatalysts for photochemical applications

Hydrothermally Treating High-Ti Cinder for a Near Full-Sunlight-Driven Photocatalyst toward Highly Efficient H₂ Evolution

A major drawback of conventional photocatalysts like TiO₂ is the limit of only working under ultraviolet irradiation. As a solution, visible-light-driven photocatalysts have been explored in recent years but full-sunlight-driven photocatalysts are still lacking. Herein, multielement-codoped (Mn, Fe, Si, Al, S, F, etc.) TiO₂ nanomaterials were prepared from an industrial high-Ti cinder (HiTi) by a two-step hydrothermal method using NaOH and NH₄F (or H₂O) as morphology controlling agents. The prepared HiTi photocatalyst exhibits a strong absorption at near full-sunlight spectrum (300–800 nm). Among all TiO₂-based photocatalysts without any noble metal cocatalyst, the photocatalytic H₂ evolution rate on NaOH- and H₂O-hydrothermally treated HiTi (HiTi-TiO₂) is remarkably superior to the reference P25 TiO₂ powders by a factor of 3.8 and thus is the highest. However, NaOH- and NH₄F-treated HiTi (HiTi-TiO₂-F) shows a lower photoreactivity than HiTi-TiO₂ does. Mechanistic studies show that the multielement-doped TiO₂ can synergistically harvest full span sunlight to greatly increase light absorption, while suppressing the charge recombination and reducing the reaction barriers for efficient water splitting. Importantly, the amount of produced industrial cinder is huge in China, and it is dumped on the ground in very large mounds, which results in serious pollution. This study may open a promising recycling approach to treat the waste for sustainable energy use