AuPd bimetallic nanoparticles decorated graphitic carbon nitride for highly efficient reduction of water to H2 under visible light irradiation

In this work, a new AuPd bimetallic cocatalyst decorated graphitic carbon nitride (g-C3N4) photocatalysts with high H-2 evolution activity was synthesized via an in situ chemical deposition method. The physical and photophysical properties of the as-prepared AuPd/g-C3N4 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscope (TEM), Ultraviolet-visible diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR) and surface photovoltage spectroscopy (SPV). The photocatalytic H-2 evolution experiments indicate that the AuPd bimetallic co-catalysts can effectively promote the separation efficiency of photo-generated charge carriers in g-C3N4, and consequently enhance the H-2 evolution activity. The 0.5 wt% AuPd/g-C3N4 catalyst shows the highest catalytic activity, and corresponding H-2 evolution rate is 326 mu mol h(-1) g(-1), which are enhanced by 3.5 and 1.6 times compared with that of pristine Au/g-C3N4 and Pd/g-C3N4 under visible light irradiation. The photocatalyst can maintain photocatalytic activity after 4 cycles. A possible photocatalystic mechanism of AuPd bimetallic nanoparticles (NPs) on the enhancement of visible light performance is proposed to guide further improvement for other desirable functional materials. (C) 2015 Elsevier Ltd. All rights reserved.