Graphitic carbon nitride (g-C3N4) loaded with gold nanoparticles (Au NPs) was first explored as a catalyst for the photoelectrooxidation of small organic molecules (SOMs) in this paper. Au/g-C3N4 nanocomposite possesses significantly enhanced photoelectrocatalytic activity under UV light illumination, compared with pure g-C3N4 and Au NPs. The prepared catalysts with different Au loading were characterized and compared by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectra (DRS) and electrochemical impedance spectroscopy (EIS). Close combination between g-C3N4 sheets and well-dispersed Au NPs is beneficial to the efficient separation of electron-hole pairs and charge transportation. The synergic effect of metallic Au NPs and polymeric g-C3N4 is responsible for the superior photoelectrocatalytic performance and is effective to mitigate the surface-poisoning species. (C) 2014 Elsevier BM. All rights reserved.