Building of multifunctional and hierarchical HxMoO3/PNIPAM hydrogel for high-efficiency solar vapor generation

Solar distillation is a sustainable and promising technique to generate fresh water. However, the solar vapor generation is a high energy consumption process, resulting in a low water yield under natural sunlight. Hence, developing of advanced evaporators that can simultaneously reduce the energy requirement of water vaporization and accelerate solar water evaporation remains a great challenge. In this study, we report the fabrication of a multifunctional hydrogel of H x MoO 3 /PNIPAM with PNIPAM as hydratable skeleton and H x MoO 3 as the light-absorbing unit for solar water evaporation. The experimental results demonstrate that the as-prepared hydrogel owns excellent photothermal activity. Accurately, the fabricated hydrogel -based solar evaporators achieved high water evaporation rate of 1.65 kg m −2  h −1 with the energy conversion efficiency of 85.87% under 1 kW m −2 irradiation. The enhanced photothermal activity of H x MoO 3 /PNIPAM hydrogel can be attributed to the synergistic effects of the components composed in this hierarchical architecture that change the water state and further speed up water evaporation. The H x MoO 3 /PNIPAM evaporators indicate its great potential for practical implementation of solar water evaporation.