The urgent need for clean and renewable energy drives the exploration of effective strategies to produce hydrogen. Semiconductor-based photocatalytic hydrogen production technology is one of the ideal processes for direct solar energy conversion and storage that has been widely studied. The development of highly efficient photocatalysts is essential for the cost-effective and large-scale production of hydrogen. CdS-based semiconductor photocatalysts have attracted significant attention due to their unique advantages, including strong visible light absorption capacity, suitable band edge levels and excellent electronic charge transfer. However, unlike TiO2 with good photostability, the intrinsic drawback of photocorrosion of CdS-based semiconductors significantly challenges their durable application in photocatalysis. This review focuses on recent advances in material design and strategies for improving the anti-photocorrosion of CdS-based photocatalysts for applications in photocatalytic overall water splitting to produce hydrogen. Moreover, brief prospective development and challenges in the synthesis of anti-corrosion CdS-based photocatalysts are also presented.

Water electrolysis is an advanced energy conversion technology to produce hydrogen as a clean and sustainable chemical fuel, which potentially stores the abundant but intermittent renewable energy sources scalably. Since the overall water splitting is an uphill reaction in low efficiency, innovative breakthroughs are desirable to greatly improve the efficiency by rationally designing non-precious metal-based robust bifunctional catalysts for promoting both the cathodic hydrogen evolution and anodic oxygen evolution reactions. We report a hybrid catalyst constructed by iron and dinickel phosphides on nickel foams that drives both the hydrogen and oxygen evolution reactions well in base, and thus substantially expedites overall water splitting at 10 mA cm(-2) with 1.42 V, which outperforms the integrated iridium (IV) oxide and platinum couple (1.57 V), and are among the best activities currently. Especially, it delivers 500 mA cm(-2) at 1.72 V without decay even after the durability test for 40 h, providing great potential for large-scale applications.

Transition metal phosphides have been investigated heavily as hydrogen evolution reaction (HER) catalysts. One of the most active transition metal phosphides, CoP, has been tested for its stability and operability under mild conditions that it may be exposed to in its applications (photoelectrochemistry and artificial photosynthesis). Surface-interrogation scanning electrochemical microscopy (SI-SECM) revealed that CoP HER catalyst is vulnerable to oxidation (by oxygen and chemical oxidants). The degradation mechanism was shown to be surface oxidation by dioxygen, followed by acid etching of the oxidized layer. The compositional integrity (unity ratio of cobalt and phosphorus) was maintained throughout the film decomposition progress.

The development of efficient water oxidation catalysts based on inexpensive and Earth-abundant materials is a prerequisite to enabling water splitting as a feasible source of alternative energy. In this work, we report the synthesis of ternary cobalt manganese phosphide nanoparticles from the solution-phase reaction of manganese and cobalt carbonyl complexes with trioctylphosphine. The CoMnP nanoparticles (ca. 5 nm in diameter) are nearly monodisperse and homogeneous in nature. These CoMnP nanoparticles are capable of catalyzing water oxidation at an overpotential of 0.33 V with a 96% Faradaic efficiency when deposited as an ink with carbon black and Nafion. A slight decrease in activity is observed after 500 cycles, which is ascribed to the etching of P into solution, as well as the oxidation of the surface of the nanoparticles. Manganese-based ternary phosphides represent a promising new system to explore for water oxidation catalysis.

Transition metal phosphides exhibit promising catalytic performance for the hydrogen evolution reaction (HER); however their surface structure evolution during electrochemical operation has rarely been studied. In this work, we investigate the surface reconstruction of CoP nanosheets by an electrochemical activation method. After remodeling, CoP nanosheets experience an irreversible and significant evolution of the morphology and composition, and low-valence Co complexes consisting of Co(OH) species are formed on the surface of CoP nanosheets, and they largely accelerate the dissociation of water. Benefiting from the synergistic effect of CoP and Co(OH), the working electrode shows a remarkably enhanced HER activity of 100 mV at 10 mA cm with a Tafel slope of 76 mV dec, which is better than that of most transition metal phosphide catalysts. This work would provide a deep understanding of surface reconstruction and a novel perspective for rational design of high performance transition metal phosphide electrocatalysts for water related electrolysis.

A simple one-pot method has been used to prepare uniform single-crystalline CoP nanowires with a high aspect ratio by the thermal-decomposition reaction of cobalt(II) acetylacetone with long-chain alkylphosphonic acid in the presence of hexadecylamine (HDA) and trioctylphosphine oxide (TOPO) at high temperature. The crystal morphology of the resulting nanowires can be influenced by the ratio of HDA and TOPO.