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

Abstract

Recently, nanosized titanium oxides have attracted much attention for the technology of interfacial solar driven water evaporation (ISDWE). Various titanium oxides, such as TiO 2 nanocage, Ti 2 O 3 nanoparticle, and TiO 2 nanotube, are favorable to provoke high water evaporation performance. In this work, ultrathin TiO 2 nanosheets coated Ti plates were developed and applied on ISDWE. The ultrathin TiO 2 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 TiO 2 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 TiO 2 -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 TiO 2 nanosheets coated square Ti plate showed a higher water evaporation rate than other shapes. Lastly, the enhanced photocatalytic activity of C, N co-doped TiO 2 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 TiO 2 nanosheet in the application of ISDWE on water purification. • TiO 2 nanosheet revealed notable high solar driven water evaporation rate. • Nanosheet structure ensured excellent light absorbility and water pumping ability. • C, N-doping can weaken the interaction energy of water-water and water-TiO 2 . • Perimeter-area ratio of Ti plate affects solar driven water evaporation rate. • Purification on unevaporated water was attained by TiO 2 nanosheet.