Knack behind the high performance CdS/ZnS-NiS nanocomposites: Optimizing synergistic effect between cocatalyst and heterostructure for boosting hydrogen evolution

Introducing co-catalyst and constructing heterostructure are two of the most promising strategies in improving the photocatalytic H2 evolution performance of semiconductors. However, it has always been a great challenge to develop a facile and low-cost system to facilitate the highly efficient synergistic effect between co-catalyst and heterostructure. Herein, co-catalyst NiS decorated ZnS/CdS heterostructure (CdS/ZnS-NiS) has been fabricated by using a facile one-pot hydrothermal procedure for the photocatalytic H2 evolution from water splitting. As a result, CdS, ZnS and NiS contact closely with each other at nano scale to assemble into fluffy porous nanocomposite, the optimized CdS/ZnS-NiS exhibits a high hydrogen evolution rate of 60.44 mmol·h-1g-1 without the addition of extra noble metal co-catalyst, which is about 22.3 times higher than that of pure CdS and much higher than that of 1% wt Pt decorated CdS/ZnS (52.36 mmol·h-1g-1). One-pot fabrication process allows the formation of intimate contacted interface between different components, contributing to the sufficient exposure of active reaction sites. Moreover, noble-metal-free co-catalyst NiS distributes uniformly in both surface and inner region of porous nanocomposite. The synergistic effect between the intimately contacted heterostructure and co-catalyst boosts the separation and utilization of photogenerated charge carriers, resulting in a dramatically enhanced H2 evolution ability. This work provides a facile pathway to uniformly introduce noble-metal-free co-catalyst in heterostructure and gives out a paradigm in constructing high active solar energy conversion system.