Enhancing photocatalytic performance by constructing ultrafine TiO2 nanorods/g-C3N4 nanosheets heterojunction for water treatment

Abstract

Photocatalysis is considered to be a clean, green and efficient method to purify water. In this report, we first developed a highly efficient ultrafine TiO2 nanorods/g-C3N4 nanosheets (TiO2 NR/CN NS) composites via a simple hydrothermal method. Tiny TiO2 nanorods (diameter: ∼1.5 nm and length: ∼8.3 nm) were first loaded in situ on the CN NS by adding graphitic carbon nitride (g-C3N4) to the reaction solution. The TiO2 NR/CN NS composites present high charge separation efficiency and broader light absorbance than P25 TiO2. Furthermore, we illustrate that the TiO2 NR/CN NS catalyst possesses high performance for the photocatalytic degradation of the common and stubborn pollutants in water, such as the rhodamine B (RhB) dye and phenol. Under visible light (λ > 420 nm) irradiation, the apparent rate of the TiO2 NR/CN NR is 172 and 41 times higher than that of the P25 TiO2 and TiO2 NR, respectively. Additionally, we speculated that the heterojunction formed between TiO2 NR and CN NS, which is the basis for the experiments we have designed and the corresponding results. We demonstrated that reactive oxidative species such as superoxide anion radical and holes play critical roles in the degradation, and the hydroxyl radical contributes nothing to the degradation.