Sulphur,nitrogen-doped TiO2/graphene oxide composites as a high performance photocatalyst

Sulphur (S), nitrogen (N)-doped TiO₂/graphene oxide (GO) composites were environmentally friendly synthesised using thiourea (CS(NH₂)₂) as a binary-element doping reagent by a simple colloidal blending method. The S, N-doped TiO₂/GO composites show higher photocatalytic degradation rates on methyl orange (MO) compared to TiO₂. The average value of k (the apparent rate constant) for the S, N-doped TiO₂/5%GO (k?=?0.035?min^?1) was found to be eight times higher than that of TiO₂ grown in solution (k?=?0.0038?min^?1) and four times higher than that of P25 (k?=?0.008?min^?1). The investigation showed that the contribution of GO to the high photocatalytic activities of the composites come from its high specific surface area, oxygen-containing functional groups and large aromatic domains that were inclined to be bound by conjugated MO molecules via π–π stacking. The doping of S and N can increase the numbers of photo-generated electrons and holes, which produce more charge carriers to form reactive species, and thus promote the degradation of MO. This work could offer a route to improve the photocatalytic activities of TiO₂ and facilitate their application in reality.