Enhanced photocatalytic activity of kaolinite-TiO2-graphene oxide composite with a porous stacking structure

A kaolinite-TiO 2 -graphene oxide composite (KTG) photocatalyst with a porous stacking structure was synthesized through a “controlled-addition” strategy. By controlling the addition timing of kaolinite and graphene oxide (GO), TiO 2 nano particles could be formed on kaolinite first, and then on GO. The successively formed kaolinite-TiO 2 composite (KT) and GO-TiO 2 composite (GT) were further assembled into a porous stacking structure. The degradation tests of methyl orange (MO) showed that the photocatalytic performance of KTG increased with the amount of GO in the range of 1–4 wt%, and KTG4 with 4 wt% GO had the best photocatalytic performance (the rate constant is 1.76 times that of KT) and obvious cost-effective advantages compared with GT without kaolinite support. The further reference experiments and computer simulation revealed the role of GO additives, kaolinite support and formed stacking structure in photocatalytic reaction, respectively. Finally, the overall improvement mechanism of photocatalytic performance of KGT was proposed.