Energy & Fuels, Vol.34, No.11, 14598-14610, 2020
Heterojunction of CdS Nanocapsules-WO3 Nanosheets Composite as a Stable and Efficient Photocatalyst for Hydrogen Evolution
CdS based nanocomposites are well reported for photocatalytic hydrogen evolution reactions because of their favorable band edge potentials. The preparation of well dispersed photocatalyst plays an important role in the enhancement of H-2 production efficiency. Among all the other morphologies of CdS, nanorods gained considerable attention due to their channeled charge carrying ability and improved surface area. Herein, CdS nanocapsules, which offer short and extensive charge carrier transport and enlarged surface area, were synthesized via the solvothermal method. Poly(vinyl pyrrolidine) was used as a capping agent for size control and better dispersion. Tungsten oxide nanosheets were synthesized via the hydrothermal route, and CdS nanocapsules were incorporated on the tungsten oxide nanosheets via the wet impregnation method. Photocatalytic hydrogen generation under solar light and simulated solar light irradiations with lactic acid as a sacrificial agent employing the prepared nanocomposite gave impressive and enhanced results, and furthermore the catayst was efficient and stable. The optimized photocatalyst showed a hydrogen production rate of about 146.2 mmol.h(-1) .g(cat)(-1). This is the highest rate reported yet for the combination of CdS and WO(3.)The Z-scheme heterojunction formation between two different morphologies plays a key role in the enhancement of H-2 generation.