Volume 4, Issue 1 (2024) – 12 articles
Cover Picture: Photoelectrochemical (PEC) water splitting facilitates the conversion of solar energy into storable and transportable hydrogen fuel. To address challenges related to freshwater scarcity, an alternative approach involves harnessing atmospheric humidity for hydrogen production. This mini-review article highlights recent advancements in vapor-fed PEC systems, specifically designed to utilize water vapor as a hydrogen resource. The PEC system utilizes a proton exchange membrane (PEM) as a solid polymer electrolyte, along with gas-diffusion photoelectrodes comprised of fibrous conductive substrate. Following the introduction of solar hydrogen production using semiconductor electrode materials and atmospheric humidity, the article delves into the development of porous oxide photoanodes employing titanium felt as a conductive substrate featuring a macroporous structure. The recent progress in the vapor-fed PEM-PEC cell is explained, focusing on the rational design of the gas-diffusion photoanodes and the triple-phase interface concept under gas-phase conditions. The porous photoanode and cathode catalyze oxygen and hydrogen evolution reactions, respectively. Finally, the article concludes by providing suggestions for future work to enhance the solar-to-hydrogen energy conversion efficiency of the PEM-PEC system. This article contributes to the Special Issue "Interface Engineering in (Photo)electrochemical Systems".
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