Developing non-noble metal photocatalysts for efficient photocatalytic hydrogen evolution is crucial for exploiting renewable energy. In this study, a photocatalyst of Ni2P/CdS nanorods consisting of cadmium sulfide (CdS) nanorods (NRs) decorated with Ni2P nanoparticles (NPs) was fabricated using an in-situ solvothermal method with red phosphor (P) as the P source. Ni2P NPs were tightly anchored on the surface of CdS NRs to form a core-shell structure with a well-defined heterointerface, aiming to achieve a highly efficient photocatalytic H2 generation. The as-synthesized 2%Ni2P/CdS NRs photocatalyst exhibited the significantly improved photocatalytic H2 evolution rate of 260.2 μmol∙h−1, more than 20 folds higher than that of bare CdS NRs. Moreover, the as-synthesized 2%Ni2P/CdS NRs photocatalyst demonstrated an excellent stability, even better than that of Pt/CdS NRs. The photocatalytic performance enhancement was ascribed to the core-shell structure with the interfacial Schottky junction between Ni2P NPs and CdS NRs and the accompanying fast and effective photogenerated charge carriers’ separation and transfer. This work provides a new strategy for designing non-noble metal photocatalysts to replace the noble catalysts for photocatalytic water splitting.

Construction of heterojunction at the atomic scale to ensure efficient charge separation for improvement of photocatalytic water splitting is challenging. Herein, a facile hydrothermal method has been applied for the in situ fabrication of TiO 2 /SrTiO 3 heterojunction, using the monolayer Ti 3 C 2 MXene as the template and reactant. It is found that the sample with the hydrothermal reaction time of 60 min exhibits the highest H 2 evolution rate with the sacrificial reagent, due to the efficient charge separation of TiO 2 /SrTiO 3 heterojunction as Ti 3 C 2 derivative. In addition, the sample shows the best overall water splitting performance at a hydrothermal reaction time of 120 min, where TiO 2 is nearly converted to SrTiO 3 , due to the fast kinetic process and low structural defects of SrTiO 3 . This work not only provides a simple strategy for the fabrication of heterojunction photocatalysts but also demonstrates the difference in optimization of half-reaction and overall water splitting reaction.

Developing efficient and stable photocatalysts is crucial for photocatalytic hydrogen production. Cocatalyst loading is one of the effective strategies for improving photocatalytic efficiency. Here, Ti3C2Tx (Tx = F, OH, O) nanosheets have been adopted as promising cocatalysts for photocatalytic hydrogen production due to their metallic conductivity and unique 2D characterization. In particular, surface functionalized Ti3C2(OH)x and Ti3C2Ox cocatalysts were synthesized through the alkalization treatment with NaOH and a mild oxidation treatment of Ti3C2Fx, respectively. ZnIn2S4/Ti3C2Tx composites, which were fabricated by the in-situ growth of ZnIn2S4 nanosheets on the Ti3C2Tx surface, exhibited the promoted photocatalytic performance, compared with the parent ZnIn2S4. The enhanced photocatalytic performance can be further optimized through the surface functionalization of Ti3C2Fx. As a result, the optimized ZnIn2S4/Ti3C2Ox composite with oxygen functionalized Ti3C2Ox cocatalyst demonstrated excellent photocatalytic hydrogen evolution activity. The characterizations and density functional theory calculation suggested that O-terminated Ti3C2Ox could effectively facilitate the transfer and separation of photogenerated electrons and holes due to the formation of a Schottky junction, with the largest difference in work function between ZnIn2S4 and Ti3C2Ox. This work paves the way for photocatalytic applications of MXene-based photocatalysts by tuning their surface termination groups.

Visible-light-driven Z-scheme photocatalytic systems are very appealing for achieving efficient overall water splitting. However, developing the Z-scheme using long wavelength responsive sulfides as H 2 -evolving photocatalysts remains challenging. Herein, the construction of Z-scheme photocatalytic systems for overall solar water splitting is described using CdS and WO 3 as H 2 -evolving and O 2 -evolving photocatalysts, respectively, in the presence of a shuttle redox mediator. The stoichiometric water splitting into H 2 and O 2 under the solar-simulated irradiation was determined through optimization of cocatalyst, shuttle redox mediator, and pH conditions. The activity attenuation during the long-term reaction was mainly attributed to the backward reaction which can be alleviated by filling the system with moderate argon. This work provides a new photocatalysts combination for the Z-scheme overall water splitting, further reflecting the importance of modulation of redox mediator environments.

Photocatalytic H 2 production holds promise for alleviating energy and environmental issues. The separation of photoinduced charge carriers plays vital roles in enhancing the activity of photocatalytic H 2 production. The piezoelectric effect has been proposed to be effective in facilitating the separation of charge carriers. However, the piezoelectric effect is usually restricted by the noncompact contact between the polarized materials and semiconductors. In this study, Zn 1−x Cd x S/ZnO nanorod arrays on stainless steel for piezo-photocatalytic H 2 production are fabricated by an in situ growth method, achieving an electronic-level contact between Zn 1−x Cd x S and ZnO. The separation and migration of photogenerated charge carriers in Zn 1−x Cd x S are significantly improved by the piezoelectric effect induced by ZnO under mechanical vibration. Consequently, under solar and ultrasonic irradiation, the H 2 production rate of Zn 1−x Cd x S/ZnO nanorod arrays achieves 20.96 μmol h −1 cm −2 , which is 4 times higher than that under solar irradiation. Such a performance can be attributed to the synergies of the piezoelectric field of bent ZnO nanorods and the built-in electric field of the Zn 1−x Cd x S/ZnO heterostructure, which efficiently separate the photoinduced charge carriers. This study provides a new strategy to couple polarized materials and semiconductors for highly efficient piezo-photocatalytic H 2 production.