2D mesoporous ultrathin Cd0.5Zn0.5S nanosheet: Fabrication mechanism and application potential for photocatalytic H2 evolution

Two-dimensional mesoporous ultrathin Cd0.5Zn0.5S nanosheets with a thickness of similar to 1.5 nm were fabricated using a multistep chemical transformation strategy involving inorganic-organic hybrid ZnS-ethylenediamine (denoted as ZnS(en)(0.5)) as a hard template. Inorganic-organic hybrid ZnS(en)(0.5), Cd0.5Zn0.5S(en)(x), and Cd0.5Zn0.5S nanosheets were sequentially fabricated, and their transformation processes were analyzed in detail. The fabricated Cd0.5Zn0.5S nanosheets exhibited high photocatalytic hydrogen evolution reaction activity in the presence of a sacrificial agent. The Cd0.5Zn0.5S nanosheets exhibited remarkably high H-2 production activity of similar to 1395 mu mol.h(-1).g(-1) in pure water with no co-catalyst, which is the highest value reported thus far for bare photocatalysts, to the best of our knowledge. The high activity of these nanosheets is attributed to their distinct nanostructure (e.g., short transfer distance of photoinduced charge carriers, large number of unsaturated surface atoms, and large surface area). Moreover, ternary NiCo2S4 nanoparticles were employed to facilitate the charge separation and enhance the surface kinetics of H-2 evolution. The H-2 production rate reached -62.2 and -2436 mu mol.h(-1).g(-1) in triethanolamine and pure water, respectively, over the NiCo2S4/Cd0.5Zn0.5S heterojunctions. The result indicated that the Schottky junction was critical to the enhanced activity. The proposed method can be used for fabricating other highly efficient CdZnS-based photocatalysts for solar-energy conversion or other applications. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

Two-dimensional mesoporous ultrathin Cd0.5Zn0.5S nanosheets with high photocatalytic hydrogen evolution reaction activity were fabricated, exhibiting remarkably high H-2 production activity in pure water. Ternary NiCo2S4 nanoparticles were utilized to facilitate charge separation and enhance the surface kinetics of H-2 evolution over NiCo2S4/Cd0.5Zn0.5S heterojunctions, with the Schottky junction being critical to the enhanced activity.