Full-Spectrum Solar Harvesting and Desalination Enabled by Supra-Nano Amorphous Ruthenium Dioxide – Mineral Composites

Breaking crystalline symmetry reveals new photonic capabilities for solar-driven technologies. Herein, a mineral-based supra-nano amorphous ruthenium dioxide composite (a-Ru_0.5-AM) is constructed. Benefiting from a defect-mediated photon-capturing mechanism in amorphous ruthenium dioxide, a-Ru_0.5-AM effectively overcomes the near-infrared absorption limitations of rutile-phase ruthenium dioxide (r-Ru), achieving an average absorption of 97% over the entire solar spectrum. Meanwhile, under one sun illumination, a-Ru_0.5-AM reaches a mean steady-state temperature of 87.91 ± 0.32 °C, and exhibits a thermal buffering effect conducive to efficient thermal confinement. In addition, surface functionalization significantly enhances the utilization efficiency of ruthenium—at equivalent Ru content, the bulk volume of a-Ru_0.5-AM is ≈10 times larger than that of r-Ru. The integrated a-Ru_0.5-AM evaporator shows an evaporation rate of 3.37 kg m⁻² h⁻¹ under one sun, with a photothermal conversion efficiency of 97.54%, while showing excellent salt-resistance, long-term stability, multifunctional water purification capability, and outstanding biocompatibility, making it suitable for diverse applications, including ecologically sensitive areas. Overall, this study endows conventional Ru-based materials with novel photothermal functions through defect engineering and surface functionalization, providing a new material design strategy and theoretical basis for applying platinum-group metals in solar steam generation, seawater desalination, and other clean water technologies.