Scalable solar-driven reforming of alcohol feedstock to H2 using Ni/Zn3In2S6 photocatalyst

• The photocatalyst-substrate specificity in alcohol photoreforming is uncovered. • Ni/Zn 3 In 2 S 6 efficiently converts benzyl alcohol to H 2 and benzaldehyde under sunlight. • A 0.5 m 2 -scale slurry photoreactor achieves an areal activity of 139 mmol h −1 m −2 . • Techno-economic assessment identifies key factors for feasibility. Organic photoreforming represents a promising pathway for solar H 2 generation with the coproduction of valuable byproducts. However, its development has been limited by separate studies on photocatalysts or photoreactors, with little focus on cost and scalability. Here we integrate photocatalyst design, upscaled photoreactor engineering, and cost analysis for the solar-driven reforming of alcohol feedstock to H 2 . The process was optimized by examining various alcohol compounds and Ni cocatalyst impact on Zn 3 In 2 S 6 photocatalytic activity. Strong interactions between Zn 3 In 2 S 6 and both aromatic benzyl alcohol substrate and Ni intensified H 2 evolution and benzaldehyde formation, achieving an apparent quantum yield of 63.8 % at 420 nm and an areal H 2 evolution activity of 278 mmol h −1 m −2 under simulated sunlight. Using the optimum conditions established in a laboratory environment, an upscaled slurry photoreactor prototype was designed and operated under natural sunlight with a 0.5 m 2 light receiving area. The upscaled solar-driven reforming of benzyl alcohol over Ni/Zn 3 In 2 S 6 delivered a H 2 production rate of 1.67 normal L h −1 , corresponding to an areal H 2 evolution activity of 139 mmol h −1 m −2 , with benzaldehyde as the major organic byproduct. A pathway for commercially viable large-scale solar-driven organic reforming was defined through techno-economic assessment. The findings are a crucial advancement in scaling photoreforming towards commercialization.