Titanium Oxynitride Spheres with Broad Plasmon Resonance for Solar Seawater Desalination

The facile production of hollow and solid nitridized submi-crometer titania spheres has been successfully realized, with potential for massproduction. The nitridation process gives submicrometer titanium oxynitridespheres, which possess a strong and broadband light absorption property.Interband-transition-induced resonance and plasmon resonance have beenfound to coexist in titanium oxynitride spheres through single-particle dark-fieldscattering measurements. Theoretical modeling has further confirmed that theexcellent light absorption properties of the oxynitride spheres originate from thesupported dual-mode optical resonance. A highly efficient, easy-to-build, andself-sustainable device is rationallydesigned for solar-driven seawaterdesalination, where the titanium oxynitride spheres function as photothermaltransducers. The hollow spheres possess a higher water evaporation rate thanthe solid ones as the inner surface of the hollow spheres also provides surfacesites for interaction with water molecules. Given the outstanding light absorption capability and the unique morphology of thehollow spheres, a water evaporation rate of similar to 1.49 kg m-2h-1with a solar-to-thermal conversion efficiency of similar to 89.1% has beenachieved under the illumination of simulated solar light (1 sun, 1 kW m-2). This marks the record performance among reportedplasmon-based solar seawater desalination systems.

Automated summary

The facile production of hollow and solid nitridized submicrometer titania spheres with strong and broadband light absorption properties has been achieved, allowing for mass production. These spheres have been used in a solar-driven seawater desalination system with record-breaking performance.