Solid state route for synthesis of YFeO3/g-C3N4 composites and its visible light activity for degradation of organic pollutants

Abstract

YFeO3/g-C3N4 composites with varying weight ratios were prepared following three different methods The optimum weight ratio and the method of preparation for enhanced visible photocatalytic activity towards the degradation of organic contaminants were identified. The successful formation of the composites was proven by XRD and IR measurements. XPS analysis shows that the inactive Y2O3 passive layer on the hexagonal YFeO3 (h-YFeO3) disappeared during the composite formation, resulting in a direct and intimate contact of h-YFeO3/g-C3N4 which is crucial for the photocatalytic activities. The loading of h-YFeO3 varied from 1 to 20% and the highest activity was achieved at 2.4%. At the optimum loading 80% degradation of methyl orange (MO) was obtained under 5 h visible light illumination. The composite photocatalyst shows also modest activity for the photodegrading of 4-chlorophenol (4-CP). Additionally the synthesized composites were characterized by high resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR) and diffuse reflection UV–vis spectroscopy (DR-UV–vis). In order to determine the relative band positions of the composite photocatalysts their flat band potentials were estimated from Mott-Schottky analysis. Improved charge separation in the composite is mainly responsible for the enhanced photoactivity and supported by photoluminescence experiments.