Synergistic effect of superhydrophilic skeleton decorated with hierarchical micro/nanostructures and graphene oxide on solar evaporation

Abstract

Solar evaporation is considered as a sustainable and environment-friendly technology to produce the fresh water. However, the significant improvement in the solar evaporation efficiency is limited by the low energy utilization rate of evaporator, unreasonable design and/or complex manufacturing processes. Herein, the innovative solar vapor generator has been manufactured by the simple chemical oxidation and physical precipitation, consisting of the copper foam and graphene oxide (GO) as matrix. The copper foam skeleton of the innovative solar evaporator decorated with micro/nanostructure limits the heat to the evaporation interface for in-situ heating, effectively generating the vapor and minimizing the heat loss. The superhydrophilic structure and oxygen-containing groups of GO play a positive role in promoting the continuous wetting and water transport. The wetting state of unfilled pores provides sufficient space for the diffusion of vapor from the evaporation interface. Findings demonstrate that the evaporation rate and efficiency of superhydrophilic copper foam solar vapor generator deposited with 1.5 mg/mL GO (SHiCF-GO-1.5) are 1.25 kg/(m2·h) and 88.9% under 1-sun irradiation, respectively. The innovative solar evaporator makes full use of skeleton to expand solar absorption and evaporation interfaces to the whole 3D structure, playing a dominant role for enhancing solar evaporation efficiency.