Effect of Annealing Temperature on the Photocatalytic Activity of ZnxCd1-Xs Photocatalyts

The Zn_xCd_1-xS photocatalyst arrays were prepared by a dispensing system and then annealed under Ar atmosphere at temperatures from 100 to 500°C to investigate the change in microstructure and the effect on the photocatalytic activity. Scanning electrochemical microscopy (SECM) with a scanning optical fiber was used to rapidly identify the best composition of Zn_xCd_1-xS photocatalyst. Among these arrays, the pure CdS at 200^oC annealing temperature exhibits the highest photocurrent under both UV-visible and visible illumination. The physic-chemical and optical properties of the potential photocatalyst were investigated by using X-ray diffraction (XRD), X-ray photoelectron spectrometric (XPS), UV-visible absorption spectra, AC impedance and incident photon to converted electron (IPCE). A possible mechanism induced by the annealing temperature to affect the photocatalytic performance of the CdS was studied in detail.