Highly efficient solar water desalination systems based on plasmonic Ni nanoparticles embedded in mesoporous TiO2 scaffold as the photothermal material

Abstract

Solar water desalination through steam generation is a promising technique with several advantages over conventional methods of water purification. In this work, a low-cost, efficient, and low-carbon footprint solar steam generator is fabricated using a photothermal layer based on non-noble plasmonic nickel (Ni) nanoparticles (Ni NPs). In this regard, Ni NPs are embedded in the mesoporous network of TiO₂ NPs as the scaffold (Ni/TiO₂ scaff.) via a simple method. Then, Ni/TiO₂ scaff. is deposited on the surface of the Ni foam skeleton (named Ni/TiO₂ @NF), creating a hydrophilic structure with hierarchical pores. Using the Ni/TiO₂ @NF porous structure as the photothermal layer, the incident photons are harvested efficiently, resulting in a remarkable water evaporation rate of 1.43 kgm⁻²h⁻¹ and a photothermal conversion efficiency of 97 %. By incorporating plasmonic Ni into the TiO₂ network, light absorption and heat generation increase because of the localized surface plasmon effect. Remarkably, the devices show no change in their performance even after 8 cycles of operation in real seawater.