Bi-function of photocatalytic Cr(VI) removal and monitoring acetone gas by one-dimensional hierarchical TiO2 @polyoxometalates@MoS2 tandem heterojunctions

Abstract

Disposal and monitoring pollutions in water and air are very important for human health and ecological environment. Therefore, developing photocatalysts and gas sensors with high-performance is more necessary and urgent. In this paper, a group of novel one-dimensional hierarchical TiO2 @polyoxometalate(PW12)@MoS2 tandem heterojunction nanofibers was firstly designed and constructed using electrospinning-hydrothermal method. The morphology, structure, and photocatalytic properties were explored. The optimized sample (TiO2 @1%PW12 @MoS2) exhibits a 79.02% degradation rate of Cr(VI), which is 27% enhancement than PW12-free TiO2 @MoS2 (62.22%). Moreover, gas sensing properties to VOC gases were also explored. It has good selectivity and sensitivity to acetone. The response to 100 ppm acetone is 10.17, which is 4.21 times that of TiO2 @MoS2. The improvement in photocatalytic and gas sensing properties can be attributed to the formation of one-dimensional TiO2/PW12/MoS2 tandem heterojunctions. PW12 can act as electron acceptors and promote carriers migration. The one-dimensional structure provides a pathway for electrons transfer. The incorporated MoS2 nanosheets can improve specific surface area. This design strategy provides a new idea for the application of polyoxometalate in environmental treatment including disposal and monitoring pollutions.