Enhancement of pollutant degradation and solar-driven water evaporation by architecting hierarchical 1D/2D TiO2 @ MoS2 core–shell networks

Abstract

Solar absorbers with a wider absorption range are attracting extensive interest in the fields of photocatalysis and solar-driven water evaporation. Here we designed hierarchical TiO2 nanowire arrays (TiO2 NWAs) in situ grown on Ti mesh, and utilizing the microstructure engineering strategy, ultrathin MoS2 nanosheets were further decorated on the surface of TiO2 NWAs (TiO2 NWAs @ MoS2). The multistage 1D TiO2 NWAs @ 2D MoS2 core–shell networks enhanced the light trapping in the full solar spectrum in comparison to bare MoS2 nanosheet arrays (MoS2 NSAs), which benefitted photocatalysis and solar-driven water evaporation. The number of photogenerated charge carriers on the surface of TiO2 NWAs @ MoS2 increased, which dramatically enhanced the photocatalytic rate constant by over an order of magnitude relative to MoS2 NSAs. As for solar-driven water evaporation, TiO2 NWAs @ MoS2 achieved a light absorption of 96.5% and a water evaporation rate of 1.42 kg m–2h−1 under one sun. In addition, the self-supporting solar absorber with favorable stability overcame the intractable recovering of photocatalysts from treated water. This study provided a pathway for designing efficient semiconductor-based solar absorbers used in solar energy conversion.