Investigation of Structure and Photocatalytic Degradation of Organic Pollutants for Protonated Anatase/Titanate Nanosheets during Thermal Treatment

Abstract

The mesoporous protonated TiO2-derived nanosheets were fabricated through an alkaline hydrothermal method. The samples with a higher specific surface area of 378 m2/g are proven to consist of anatase and titanate phases. The X-ray diffraction studies and Raman spectroscopy techniques are employed for investigating structural transformation of the nanosheets caused by thermal treatment. During the thermal treatment from room temperature to 550 °C, the titanate phase gradually transformed to anatase phase, resulting in the destruction of the nanosheet structure. Particularly, the anatase phase is not observed to grow at the temperatures below 300 °C. The pore volume and specific surface area decrease under thermal treatment, which is ascribed to dehydration. The efficiency of gaseous- and liquid-phase-based photocatalytic activity of the materials is assessed by employing the photodegradation of gaseous benzene and rhodamine B (RhB), respectively. The photocatalytic activities of the samples are strongly influenced by conversion of the phase structure, pore volume, and specific surface area during the thermal treatment. This shows a significant impact on the efficiency of separation and transfer of photogenerated charge carriers.