Design of ultrathin TiO2 nanosheets coated Ti plate for enhanced interfacial solar driven water evaporation performance

Recently, nanosized titanium oxides have attracted much attention for the technology of interfacial solar driven water evaporation (ISDWE). Various titanium oxides, such as TiO2 nanocage, Ti2O3 nanoparticle, and TiO2 nanotube, are favorable to provoke high water evaporation performance. In this work, ultrathin TiO2 nanosheets coated Ti plates were developed and applied on ISDWE. The ultrathin TiO2 nanosheet was obtained through hydrothermal treatment of Ti plate in aqueous NaOH solution, and C, N co-doping was realized through adding methionine in the solution. As the formation of nanosheet and C, N co-doping, the TiO2 nanosheets coated Ti plate exhibited enhanced solar light absorbility, water pumping ability, and specific surface area. Molecular dynamics simulations also indicated that the water-water and TiO2-water interactions can be weakened by C, N co-doping. Owning to the above reason, a notable high water evaporation rate of 1.57 kg•m−2•h−1 was achieved. Furthermore, the shape of Ti plate also affected the ISDWE performance, C, N co-doped TiO2 nanosheets coated square Ti plate showed a higher water evaporation rate than other shapes. Lastly, the enhanced photocatalytic activity of C, N co-doped TiO2 nanosheets coated Ti plate also enabled purification of unevaporated water and stable water evaporation rate during ISDWE experiment on RhB solution. This report highlights the advantages and potential of TiO2 nanosheet in the application of ISDWE on water purification.