| How to improve the quantum efficiency of H2-evolution has been a focus of huge interest in the field of photocatalyttic water splitting.Considering the suitable bandgap and sufficiently negative conduction band position to thermodynamically drive the water reduction reaction,Zn-Cd-S solid solution is an ideal photocatalyst with potential applications in solar hydrogen production.Unfortunately,the requirement of noble metals cocatalysts together with the utilization of poisonous sulfur sources restricts its commercial application.This work focuses on the fabrication and assembly of nanostructured metal sulfide photocatalysts with high efficiency and stability by a facile and green strategy,which is environmental-friendly and inexpensive.?1?Narrow bandgap hexagonal Zn-Cd-S solid solution photocatalysts?Eg=2.11-2.53eV?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 represents a significant advance in the green synthesis of metal chalcogenides,which can be used directly?cocatalyst-free?for highly-efficient solar H2production.?2?Cubic ZnxCd1-x S nanocrystals with the band energy of 2.11-3.19 eV were fabricated at a moderate temperature by a L-cystine-assisted hydrothermal approach.Specially,cocatalyst-free Zn0.9Cd0.1S in an aqueous solution containing S2-and SO32-ions shows a super high H2-production activity of 8346.9 umol h-1 g-1,corresponding to a Q.E.of 33.7%at 420nm. |
PDF Full Text Request