Recent advancements in Se- and Te-enriched cocatalysts for boosting photocatalytic splitting of water to produce hydrogen

One of the most significant boosts for reducing energy consumption and environmental pollution is expected to be the photocatalytic splitting of water, which is a cost-effective and ecologically beneficial method of hydrogen (H 2 ) production from water under sunlight irradiation. Researchers have studied various photocatalytic materials and systems for the last 50 years; however, there are still some challenges in enhancing the lifetime of photo-generated charge carriers, their efficient reactivity, and enabling the use of longer wavelengths of incident light for an efficient production of H 2 under sunlight irradiation. In this situation, recent studies have shown that selenium (Se)- and tellurium (Te)-enriched cocatalysts is crucial in photocatalytic systems for the efficient conversion of solar energy into H 2 production. They provide a variety of benefits, including efficient photo-generation of charge carriers and their efficient transfer, increase in the number of active sites, enhancement in the electronic conductivity, and optimization of cocatalyst-H ads bonds. In the present review, the advancements in photocatalytic H 2 evolution reactions (HER) using Se- and Te-enriched cocatalysts are discussed in detail. In particular, the construction of novel transition metal-based Se- and Te-enriched cocatalysts are summarized, followed by their benefits, comparison, and mechanisms to improve photocatalytic water splitting. Finally, as conclusions, a comprehensive outlook on the research development of Se- and Te-enriched cocatalysts is identified as a major challenge, and various ways to overcome the lower efficiency of photocatalytic HER are suggested by showing an appearance of cocatalysts enriched in Se and Te elements is one of the highlights in the photocatalytic HER research field.