Enhanced photocatalytic H2 production activity of CdZnS with stacking faults structure assisted by ethylenediamine and NiS

Abstract

In order to enhance the visible light-driven photocatalytic H2 production activity of CdZnS, an ethylenediamine-assisted hydrothermal pathway was used to synthesize CdxZn1-xS(en) with different Cd/Zn molar ratios. It was found out that the prepared Cd0.5Zn0.5S(en) possessed the highest photocatalytic H2 production rate of 13539.0 μmol h−1 g−1 that was higher than that of CdZnS. The key to this achievement could be ascribed to the stacking faults formation, the optimum band gap with conduction band position and small crystallite size. Based on this, Cd0.5Zn0.5S(en) was modified by NiS for further improving the activity. The obtained Cd0.5Zn0.5S(en)NiS with NiS loading content of 0.25 wt% exhibited much higher photocatalytic H2 production rate, reaching up to 38187.7 μmol h−1 g−1 that were among the highest efficiencies for semiconductor photocatalysts ever reported. It was confirmed that the nanosized NiS anchored on Cd0.5Zn0.5S(en) interface, acting as electron trapping sites, attributed to the spatial suppressions of electron-hole recombination. Meanwhile, the NiS loaded on the surface optimized the photogenerated electron transfer pathway between the semiconductor materials that gives rise to significantly enhanced photocatalytic activity. This study would put forward a facile method for developing high photocatalytic activity and low-cost catalytic material for H2 production, which provide a new thought to address the global energy crisis and the environmental contamination.