Porous architectures based on halloysite nanotubes as photothermal materials for efficient solar steam generation

Solar steam generation assisted by photothermal materials has attracted extensive attention due to its advantages of excellent evaporation rate and high photothermal conversion efficiency. In this work, we report a simple method by employment of halloysite (Hal) nanotubes (HNT) and graphene oxide (GO) as raw materials to produce efficient solar photothermal materials (named as GO-HNT). The as-prepared GO-HNT has rich porosity, excellent 90% light absorption and good thermal insulation performance (thermal conductivity 0.162 W m −1  K −1 ). Based on these characteristics, GO-HNT can be used as a promising solar receiver. Correspondingly, the solar energy conversion efficiency of the GO-HNT solar receiver was measured to be 83.67%, 77.17% and 77.05% respectively under 1 sun, 2 sun and 3 sun irradiations. As a 1D nanocrystalline clay mineral, HNT have great advantages of environmentally friendly, cost-efficient and commercial availability with abundant reserves. In combination with its simple and scalable manufacture method, this GO-HNT-based solar receiver may hold great potentials for a broad range of applications, such as seawater desalination, distillation, sterilization, sewage treatment, etc.