A game-changing design of low-cost, large-size porous cocatalysts decorated by ultra-small photocatalysts for highly efficient hydrogen evolution

Photocatalytic hydrogen production from water splitting has received considerable attention in recent years. The bottle-neck issue for hydrogen production efficiency is the relative slow charge separation and efficient hydrogen evolution. Currently, the major strategy for developing catalysts is to anchor small noble-metal cocatalysts onto relatively large photocatalysts. In this study, extremely small photocatalysts of TiO2 quantum dots were loaded onto the low-cost micro-sized cocatalysts of porous NiO/NiS2 nanosheets, promoting the rapid charge separation of photogenerated electrons from small-sized photocatalysts to large-sized cocatalysts. The size of cocatalysts is three orders of magnitude larger than that of photocatalysts. The hydrogen production of designed catalysts is ∼ 16 times higher than that of pure TiO2 photocatalysts, clearly demonstrating the critical role of large-sized porous cocatalysts. Our game-changing strategy provides a distinctive approach to design new kinds of photocatalysts with rapid charge separation and highly efficient hydrogen evolution.