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

Abstract

In this work, a new AuPd bimetallic cocatalyst decorated graphitic carbon nitride (g-C3N4) photocatalysts with high H2 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 H2 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 H2 evolution activity. The 0.5wt% AuPd/g-C3N4 catalyst shows the highest catalytic activity, and corresponding H2 evolution rate is 326μmolh−1g−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.