Two-in-One Integrated System—Solar Energy Activated Interfacial Collaborative Conversions of Photo-Chemical and Photothermal Coupling Reactions

Abstract

Realization solar energy driven photochemistry and photothermal coupling reaction is an efficient strategy to break through the limitation of traditional single function. In this paper, a two-in-one interfacial integrated system is constructed via in-situ self-assembly of 3DOM-TiO2/Cu2SnS3 composite into PVDF membrane. On the one hand, the integrated system possesses the strong sunlight capture ability in the whole UV-Vis-NIR region because of the narrow band gap characteristics of Cu2SnS3 and the three-dimensional ordered macroporous (3DOM) structure of TiO2, which exhibits the excellent photothermal conversion performance, accelerating interfacial water evaporation and realizing seawater desalination reaction in liquid-solid phase. On the other hand, 3DOM-TiO2/Cu2SnS3 composite produce electron-hole pairs under sunlight irradiation. The photogenerated holes could oxidize interfacial water vapor to release protons, and the photogenerated electrons could convert CO2 gas and protons into CO, which achieve photocatalytic CO2 reduction reaction in gas-solid phase. As a result, a collaborative conversion of photochemical and photothermal coupling reactions is achieved, with 27.36 μmol/g of product yield from CO2 reduction and 3.71 kg/cm2 of evaporation efficiency from seawater desalination after sunlight irradiation for 4 h. Furthermore, the integrated system exhibits the long-term stability and recyclable characteristic on the basis of PVDF supporter membrane, which would produce no secondary pollution and reduce the reaction cost. This integrated system exhibits the important application value in the co-production of CO2 resource utilization and seawater desalination.

Keywords: Integrated system, coupling reaction, photothermal seawater desalination, photocatalytic CO2 reduction, PVDF/3DOM-TiO2/Cu2SnS3