Polytype wurtzite-nH ZnS (n = 2 and 8): facile synthesis and photocatalytic hydrogen production under sacrificial reagents

Abstract

Zinc sulfide, as an excellent catalyst, has attracted a lot of attention from scholars owing to its photocatalytic hydrogen evolution from water splitting in the ultraviolet (UV) region. In this work, polytype wurtzite-nH ZnS (n = 2 and 8) was synthesized successfully using thiourea (SCN₂H₄) as the sulfur source by hydrothermal and solvothermal methods. Compared with ZnS nanosheets and ZnS nanowires (2H), the ZnS hollow nanosphere (8H) photocatalysts exhibited the best light capturing ability, longest electric charge lifespan and highest electron (e⁻) and hole (h⁺) separation efficiency, which contributed to the superior photocatalytic hydrogen production activity. The photocatalytic hydrogen evolution rate (10.35 mmol h⁻¹ g⁻¹) of ZnS hollow nanospheres (8H) with good photostability was measured under the support of solar-light irradiation, and the highest apparent quantum efficiency (AQE) of 6.4% was recorded. This work not only presents the effects of the morphology and stacking order of crystal forms on the hydrogen production performance of photocatalysts, but also provides new insights into the construction of solar-light-driven catalysts for H₂ production from H₂O splitting.