Stepwise photoassisted decomposition of carbohydrates to H2

Biomass reforming by harvesting solar energy can provide green hydrogen. Current biomass photoreforming provides H2 erratically and in limited yield although efficiently, owing to intermittent features of solar light and incomplete degradation of biomass C–C bonds. Here, we detour the flaws by prioritizing conversion of carbohydrates to liquid hydrogen carriers (LHCs, consisting of HCOOH and HCHO), appropriate for transportation. Subsequently, the LHCs are fully decomposed, releasing only H2 and CO2. This stepwise process enables complete scission of carbohydrate C–C bonds, affording 44 g of H2 per kg of glucose thereof. Intermittent solar light provides the photoenergy and heat to split glucose carbons to produce LHCs (2.5 mmol h−1) in a flow apparatus. This work demonstrates hydrogen production and storage by emphasizing the complete scission of biomass C–C bonds.