Carbon-Supported Nano Tungsten Bronze Aerogels with Synergistically Enhanced Photothermal Conversion Performance : Fabrication and Application in Solar Evaporation

Solar interfacial evaporation is an effective and sustainable strategy to solve the shortage of fresh water. Nowadays, fully converting the near-infrared light with significant thermal effect, and reducing the energy loss in evaporation stage are the key factors to achieve higher evaporation rate. Herein, the nano cesium tungsten bronze (Cs0.32WO3) with exceptional near-infrared absorption property was loaded on reduced graphene oxide-carbon nanotubes (rGO-CNTs) composite aerogel, drastically enhancing the photothermal conversion efficiency from 61.0% to 85.9%, which can be explained by the remarkable synergistic effect between rGO-CNTs and nano Cs0.32WO3 in improving the thermal energy output performance. As a result, the solar evaporators assembled by the fabricated rGO-CNTs-Cs0.32WO3 aerogels and corn straw grooves achieved an evaporation rate of 1.93 kg×m-2×h-1, exceeding the previously-investigated carbon aerogels/foams, natural plants and tungsten-based compound systems. The characterization results reveal that the partial thermal energy generated by the local surface plasma resonances (LSPR) effect of nano Cs0.32WO3 can be transferred to the surrounding rGO-CNTs, improving the transition frequency of ground state electrons and corresponding relaxation effect in rGO-CNTs. Meanwhile, the rGO-CNTs provide more oxygen vacancies and carriers for Cs0.32WO3, which further enhances the LSPR effect. Significantly, the hydrophilic functional groups and excellent wettability of composite aerogel and corn straw play crucial effect in accelerating water transport, activating water molecules and reducing evaporation energy consumption. In a word, the unique construction of rGO-CNTs-Cs0.32WO3 aerogels presents a novel approach for the design of solar-driven freshwater production system, the application expansion of nano tungsten bronze and carbon aerogels