Controllable oxygen doping and sulfur vacancies in one dimensional CdS nanorods for boosted hydrogen evolution reaction

Abstract

Photocatalytic hydrogen evolution reaction (HER) on semiconductor surface has attracted a great attention in recent years for their abundant applications in solar energy conversion and environmental remediation. Even though a number of materials have been designed for HER, still suffer from little photocatalytic activity which restricts the practical applications. Introducing the vacancies and doping is an effective approach to control the electronic bandstructures of materials which in turn results the improved photocatalytic activity. In this study, we have synthesized one dimensional CdS nanorods by a solvothermal method and then developed a low temperature heating strategy to incorporate the O-doping and S-vacancies simultaneously into CdS towards visible photocatalytic H2 evolution reaction. The heat treated samples with controlled O-doping and S-vacancies offer enhanced visible light absorption and improved photogenerated charge carriers’ separation. Moreover, the S-vacancies also acted as traps to retard the electron-hole recombination rate. As a result, CdS sample treated at 200 °C for 2 hr showed a high photocatalytic H2 evolution activity of 377 μmol/g/h which is 22 times higher than 18 μmol/g/h for pure CdS sample. This work validates a simple thermal treatment method to produce S-vacancies and O-doping for the fabrication of efficient photocatalysts for solar hydrogen production.