Efficient photocatalytic degradation of methylene blue by using GO/hemin/TiO2 nanocomposite under visible irradiation

A hybrid photocatalyst with high photocatalytic activity under visible light was developed. The photocatalyst - graphene oxide (GO)/hemin/titanium dioxide (TiO2) nanocomposite was prepared by a simple method via adsorption at room temperature within 3 h, and was characterised using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV-Vis spectroscopy. The results show that TiO2 nanoparticles were dispersed on the surface of GO sheets uniformly, and the crystal structure remained the same as original anatase TiO2 phase in the presence of GO and hemin. Extended absorption of the nanocomposite into the visible region is benefit for the novel hybrid photocatalyst to utilise visible light more efficiently in the photocatalytic reaction. The photocatalytic activity increased about 70% in the presence of GO and hemin (96%) comparing to pure TiO2 (26%). The nanocomposite catalyst could stably adsorb and degrade methylene blue of different concentration without H2O2 or sacrificial electron donor at a relatively wide range of pH values within 3 h. As well as, the prepared GO/hemin/TiO2 nanocomposite shows good stability and reusability in the photocatalytic reaction, enabling it a potential application in wastewater treatment.