In situ synthesis of CdS/CdWO₄ nanorods core-shell composite via acid dissolution

The prevention of photocorrosion in photocatalysts allows for the use of a wide variety of visible-light-responsive photocatalysts, leading to highly efficient photocatalytic reactions. This study aimed to avoid the photocorrosion issues associated with pure CdS, a known photocorrosive photocatalyst, by forming a stable CdWO₄ shell on the surface of a CdS core. The CdS/CdWO₄ core-shell composite was formed using a unique method based on CdS elution under acidic conditions. An optimal CdWO₄ nanorod shell was formed at a pH of 0.8, a reaction time of 30 min, and a calcination temperature of 400 °C, where the core remained intact and was sufficiently coated. The prepared CdS/CdWO₄ core-shell composite was shown to be stable when exposed to light irradiation in pure water. Furthermore, it was successfully used in water splitting with an oxidation reaction side photocatalyst. This core-shell synthesis method based on core dissolution was easily and highly controlled, and is suitable for use in other similar core-shell composite applications.