S-scheme heterojunction photocatalysts for hydrogen production: Current progress and future prospects

A technological breakthrough and substances that offer real solutions to ecological problems are essential for societal growth in the future. Besides, the challenging technique has turned up hydrogen production by solar photocatalysts in the pace of lacking sustainable energy without carbon exhaust to provide an environmentally friendly and feasible progress. Numerous studies and initiatives were made to improve the conversion of energy production into green fuel utilizing the photocatalytic method. Developing an alternative hydrogen fuel using solar driven water splitting plays a crucial role in achieving carbon neutrality and environmental management. Understanding the photocatalytic pathways is crucial for building an appropriate semiconducting heterojunction, and the problems of solar water splitting are dedicated to this. This review briefly discusses the different types of hydrogen production methods. In this framework, the principles of photocatalysis were defined with their varying homogeneous and heterogeneous catalytic combinations. Further, various scheming of photocatalysts such as Z-scheme and S-scheme were described in detail. S-scheme photocatalysts have recently been researched hotspots, due to their excellent redox activity, charge carrier separation, and capacity to act under visible light. In this review, the evolution of S-scheme photocatalysts was described and evaluated, beginning with Z-scheme photocatalysts, and ending with S-scheme photocatalysts. The benefits of S-scheme photocatalysts are also thoroughly examined, covering the design concepts and construction methodologies, and charge transfer mechanisms. Various characterization techniques for determining the S-scheme photocatalysts were discussed. The most recent innovations in their applications in the production of hydrogen evolution were also discussed. To conclude, the future prospects of S-scheme photocatalysts were discussed.