Preparation of carbon spheres supported CdS photocatalyst for enhancement its photocatalytic H2 evolution

Abstract

In this work, we prepare a series of carbon spheres (CSs) supported CdS photocatalyst via simple co-precipitation combined aging method towards the photocatalytic hydrogen production under visible light irradiation. The synthesized photocatalysts are characterized by X-ray diffraction, UV–vis diffuse reflectance spectroscopy, Nitrogen adsorption–desorption measurement, scanning electron microscopy (SEM) and so on. The UV–vis diffuse reflectance spectroscopy shows that all of the CSs/CdS samples can respond more visible-light than pure CdS. The SEM and TEM images demonstrate that the 1% CSs/CdS sample have less aggregation than pure CdS, which can provide more reactive sites and benefit the photocatalytic reaction. The results of photocatalytic experiments prove that the CSs/CdS composites exhibit a significantly enhanced photocatalytic activity for H2 production compared with pure CdS under visible light irradiation. Especially for the 1% CSs/CdS sample, the average H2-production rate reaches 583μmol/h, nearly 1.8 times than that of pure CdS. The enhanced photocatalytic activity of the CSs/CdS composites can be attributed to the large surface area of CSs/CdS samples and good electroconductivity of CSs, which can effectively separate the photo-generated electron-hole pairs of CdS. This method effectively improves the photocatalytic activity of CdS. In addition, the possible photocatalytic mechanism of CSs/CdS composites for H2 evolution is proposed.