Medium-entropy engineering of layered double oxides enables efficient photo-thermal hydrogen production from NaBH4 hydrolysis

A major challenge in photo-thermal catalytic hydrogen production from NaBH 4 hydrolysis is developing catalysts that are efficient, stable, and cost-effective. Here, we report a medium-entropy photo-thermal catalyst, Co 6 FeAlNi x -LDO, with tunable Ni doping. Ni incorporation transforms the morphology from nanosheets to hierarchical flower-like structures, increasing surface area and enhancing broadband light absorption (200-800 nm) and photo-thermal conversion. Under visible light without external heating, Co 6 FeAlNi 2 -LDO achieves a hydrogen evolution rate of 12,791.7 mL min −1 ·g −1 , nearly ten times higher than undoped Co 6 FeAl-LDO. The catalyst also shows excellent durability, retaining 98% activity after five cycles, with easy magnetic recovery. Mechanistic studies reveal that photo-generated holes (h + ) and hydroxyl radicals (•OH) are the dominant active species, while synergistic interactions among Co, Fe, Al, and Ni improve surface reactivity, charge carrier density, and charge transfer, resulting in enhanced hydrogen production.