Photoelectrochemical water splitting with engineering aspects for hydrogen production: Recent advances, strategies and challenges

A potentially successful method for absorbing solar energy and preventing climate changes brought on by the burning of fossil fuels is the production of solar hydrogen. Despite enormous potential for future uses, solar energy is seen to be the most alluring and sustainable of the renewable energy sources powering water splitting. Photovoltaic (PV), photocatalytic (PC) and photo-electrochemical (PEC) are the three primary methods for producing hydrogen from solar energy. For the production of direct solar hydrogen, the PEC water splitting holds promise. Numerous advantages of PEC water splitting include its comparatively high solar to chemical energy conversion, simple and safe product collection, high reliability, and sustainability in a massive generation. The main objective of this review is to provide a thorough analysis of the engineering aspects of the PEC method that are readily available for stimulating hydrogen production with main challenges and advances. In the first part, an overview of recent advancements in solar H2 generation, along with the fundamental operating principles, reactor design, efficiency and durability are discussed. This review also explores and analyses solar technologies based on solar-to-hydrogen (STH) efficiency, resilience, commercial affordability, and environmental sustainability to compare them to the present industrial H2 generation methods. The efficiency trend indicates that PV-EC systems have the highest STH efficiency (32%), preceded by PEC (19%) and PC systems and solely PV−EC systems can ensure over a decade of long-term durability for feasible solar production of hydrogen. Although the PEC system's estimated LCOH is 8.43 $/kg H2, this research shows that it is improbable that the system will produce hydrogen at a cheaper price or with greater application flexibility. Lastly, the challenges and prospects for additional PEC technology research are explored.