Biomolecule-assisted hydrothermal synthesis of ZnxCd1−xS nanocrystals and their outstanding photocatalytic performance for hydrogen production

To achieve scalable applications in solar hydrogen production, it is necessary to develop visible-light-responsive photocatalysts that are highly efficient, cost-effective, stable and environmentally-benign. Here narrow bandgap Zn-Cd-S solid solution photocatalysts (Eg = 2.11-2.53 eV) were prepared via a facile and green hydrothermal strategy under mild conditions. Amazingly, over the naked Zn0.5Cd0.5S photocatalyst, an extraordinarily high H2 production activity in Na2S-Na2SO3 aqueous solution is achieved up to 18.3 mmol h−1 g−1 with an apparent quantum efficiency of 73.8% per 50 mg under 420 nm light irradiation, which, to our knowledge, outperforms cocatalyst-free metal sulfide photocatalysts previously reported to date. Such super high performance arises from the enhanced visible-light-absorption capacity, suitable conduction and valence band potential together with the facilitated charge transport in Zn-Cd-S solid solutions. This work may open an avenue for the green preparation of inexpensive photocatalysts for solar H2 production.