▎ 摘　　要

CdS modified with reduced graphene oxide (RGO) has been widely demonstrated to be effective in the field of solar-energy conversion. However, the inherent mechanism of this superior property is still not thoroughly understood. Thus the photoelectrochemical method was employed to systemically investigate the synergetic effect between CdS and RGO. The result shows that the photoelectrochemical properties of RGO/CdS samples are sensitive to the relative ratio of RGO to CdS, and the photoelectrode with 1.0wt% ratio of RGO possesses the best photoelectrochemical performance. Further investigation demonstrates that the synergetic effect between CdS and RGO directly influences the charge-transport property and band-structure of the composite, which is also supported by the X-ray photoelectron spectroscopy data and first-principle simulation, respectively.