TiO2/reduced hydroxylated graphene nanocomposite photocatalysts: Improved electron–hole separation and migration

Abstract In the catalytic process of semiconductor, the rapid recombination of electron-holes greatly reduces the catalytic activity of the semiconductor catalyst. In this study, a low-defect reduced hydroxylated graphene (RGOH) was used as a carrier material to prepare TiO2/reduced hydroxylated graphene (T/RGOH) nanocomposite photocatalyst by one-step hydrothermal method. The nanocomposite photocatalysts were used to degrade methylene blue (MB). The degradation efficiency of MB catalyzed by T/RGOH nanocomposite photocatalyst was about 48.5% higher than that of the pure TiO2, and about 19.7% higher than that of the TiO2/reduced graphene oxide (T/RGO) nanocomposite photocatalyst. This was because the electrical conductivity of RGOH was much higher than that of RGO, which greatly improved the separation and migration efficiency of photogenerated electron-holes. At the same time, there might exist the Ti–O–C bond in the T/RGOH, which was advantageous to transfer photogenerated electrons through this bond to the RGOH flakes and prevented rapid recombination of photogenerated electron-holes. This study indicated that the preparation of catalyst nanocomposites using RGOH as carrier was an effective method to improve the catalytic performance of semiconductor catalysts.