This study presents a highly efficient approach to solar hydrogen production by pairing water electrolysis with the selective oxidation of biomass-derived glucose. Central to this advance is a copper-doped cobalt oxyhydroxide catalyst that guides glucose through a finely tuned cascade of α–C–C bond cleavages, producing up to 80% formate while simultaneously lowering the anodic potential by nearly 400 mV. This design enables hydrogen generation in a simple membrane-free reactor, achieving pr