Employing photocatalysis for water splitting to generate hydrogen (H₂) is regarded as a highly viable strategy for attaining green and efficient H₂ production. However, photocatalysis faces significant challenges in charge separation and instability. Notably, sulfide-based photocatalysts are often severely limited by photocorrosion issues. In this work, we employed a NiMoO₄/twinned Mn_0.5Cd_0.5S (NiMoO₄/T-MCS) heterojunction as a model catalyst. By modulating the alkalinity of the aqueous solution to promote rapid consumption of photogenerated holes (h⁺), the surface reaction kinetics was greatly enhanced, achieving an exceptional H₂ evolution rate (r_H2) of 28.22 mmol·g^-1·h^-1 in 4 M NaOH solution. The external NaOH facilitates the water oxidation half-reaction, preferentially consuming photogenerated h⁺ to generate ·OH radicals. This process triggers surface hydroxylation, significantly boosting both catalytic activity and stability. Furthermore, the generated ·OH radicals effectively degrade methylene blue (MB). Critically, the substantially enhanced surface reaction efficiency—particularly the rapid consumption of photogenerated h⁺—dramatically improves the system’s operational stability. This study demonstrates concurrent H₂ production and pollutant purification solely through solution modulation, alongside a significant enhancement in system efficiency.

Red phosphorus (RP), as a promising non-metallic photocatalyst, has garnered considerable attention due to its unique structural characteristics and exceptional optoelectronic properties. While previous reviews have explored RP-based photocatalysis, recent advancements in fabrication strategies, characterization techniques, and theoretical modeling have significantly reshaped the design, synthesis, and optimization of these materials. This review provides a comprehensive and critical evaluation of the latest progress in RP-based photocatalysts over the past five years, with a particular focus on strategies aimed at enhancing light harvesting capabilities, improving the separation and transport of photogenerated charge carriers, and ensuring long-term stability. Particular emphasis is placed on the role of innovative in-situ characterization techniques and density functional theory (DFT) simulations in elucidating the underlying photocatalytic mechanism across diverse applications, including photocatalytic hydrogen evolution, CO₂ reduction, bacterial disinfection and organic pollutant degradation. Finally, this review highlights emerging challenges and forward-looking strategies to further boost the photocatalytic performance of RP-based systems, offering valuable insights for the rational design of next-generation non-metallic photocatalysts.

Twinned Mn_0.5Cd_0.5S (T-MCS) solid solution was prepared by a hydrothermal method, and then Zn_0.76Co_0.24S/T-MCS heterojunction was fabricated by an in-situ hydrothermal method. The results show that Mn_0.5Cd_0.5S solid solutions is a twinned homojunction consisting of wurtzite Mn_0.5Cd_0.5S (WZ-MCS) and zinc-blende Mn_0.5Cd_0.5S (ZB-MCS) alternately. The introduction of Zn_0.76Co_0.24S can enhance the light harvesting ability of the system and increase the number of the surface charge carriers, the H₂ production rate of 3% Zn_0.76Co_0.24S/T-MCS reaches 132.9 mmol·g⁻¹·h⁻¹ in Na₂S/Na₂SO₃ mixture solution (300 W Xe lamp, λ > 420 nm), which is 332.2 and 1.9 times greater than those of Zn_0.76Co_0.24S and T-MCS, respectively. According to the results by energy band structure analysis, the type-II twinned homojunction between WZ-MCS and ZB-MCS can improve the bulk phase charge separation, the S-scheme heterojunction between T-MCS and Zn_0.76Co_0.24S can accelerate the interfacial charge transfer, and the REDOX capacity of the holes in T-MCS valence band and electrons in Zn_0.76Co_0.24S conduction band is retained, therefore resulting in a faster H₂ production.