Synthesis of a visible-light active V2O5–g-C3N4 heterojunction as an efficient photocatalytic and photoelectrochemical material†
Abstract
A new V2O5–g-C3N4 nanocomposite was synthesized via a wet impregnation method using V2O5 and g-C3N4, obtained from citric acid and urea. The phase purity, crystallite size and strain were ascertained by powder X-ray diffraction (XRD) analysis. Furthermore, the synthesized photocatalysts were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS) and photoluminescence spectroscopy (PL). The efficiency of the photocatalysts was evaluated by the photodegradation of direct red 81 (DR81), a target textile pollutant, under visible light irradiation. The photocatalytic experiments demonstrated that the V2O5–g-C3N4 composites showed much better photocatalytic degradability of DR81 than bulk V2O5 and g-C3N4, when used individually. The enhancement of photocatalytic degradation is attributed to the efficient charge carrier separation of photogenerated electron–hole pairs. PL and electrochemical impedance spectroscopic (EIS) results also support the above statement. Different mol% ratios (1, 2 and 3%) of V2O5 loaded composites have been prepared and a 1% loaded composite was found to show optimal efficiency. A possible mechanism has been proposed for the photocatalytic degradation using V2O5–g-C3N4.