Ultrasonic-microwave assisted synthesis of GO/g-C3N4 composites for efficient photocatalytic H2 evolution

Abstract

There has been increasing interest in the study of photocatalysis technology application in hydrogen production by splitting water because of environmental pollution and energy utilization. In this study, a high efficiency of the photocatalytic H2 production was achieved via graphene oxide (GO) and graphitic carbon nitride (g-C3N4) composite photocatalysts (GO/g-C3N4). The GO/g-C3N4 photocatalysts possessed enhanced activities for hydrogen production than pure g-C3N4 under visible light irradiation. The structural and optical properties of all the synthesized photocatalysts were successfully characterized by XRD, FTIR, XPS, UV–vis spectra, TEM, SEM, N2 adsorption-desorption and photoluminescence spectra techniques. Experimental results indicated that GO/g-C3N4 photocatalysts can reach a high H2-production rate of 224.6 μmol/h (nearly 12 times of that obtained from pure g-C3N4) at GO content of 0.5 wt % and Pt 1 wt % under visible light irradiation. The enhanced photocatalytic activity of GO/g-C3N4 is ascribed to the ability of GO in accepting and transporting electrons from excited g-C3N4, which promotes the charge separation. This work highlights that the affordable and abundant carbon material can be a good candidate for an electron attracting collector and transporter to efficiently lengthen the lifetime of the photogenerated charge carriers in the field of photocatalytic hydrogen production.