Hosseini, SaharTorres, Juan F.2026-07-032026-07-030038-092XORCID:/0000-0002-3054-8638/work/219172788ORCID:/0000-0003-3701-3975/work/219178399https://hdl.handle.net/1885/733812757Concentrating solar power (CSP) is a renewable energy technology that converts concentrated sunlight into thermal energy. Central-receiver (solar-tower) systems are a CSP configuration whose efficiency and longevity depend on the performance of solar absorber coatings. These coatings degrade due to various factors, including soiling from sandstorms in desert environments that reduce their solar absorptance. This study investigates the impact of severe artificial soiling on the optical degradation of two types of coatings: Pyromark 2500 and a hierarchical coral-structured coating. To achieve this, the coatings were exposed to 50 mg of China sand dust, a standard sand deposited on the coating as a contaminant. Their absorptance, chemical composition and morphological changes were analysed before and after 400 h of ageing at 800 and 900 °C. The results indicate that the extent of the sand coverage influences absorptance degradation, which is more pronounced in the coral-structured coatings as the sand particles fill the gap between macro-scale protrusions, reducing the light-trapping performance induced by multiple reflections. Furthermore, the effect of temperature on absorptance degradation is less significant at 900 °C due to the likely structural changes in sand dust at higher temperatures. This work elucidates the impact of sand soiling on the performance of both conventional and advanced solar absorber coatings.Ms Kaoru Tsuda from Nano Frontier Technology provided the coral-structured coating samples. This research was funded in part by a Research Pilot Project Grant from the NSW Space Research Network, an initiative of the New South Wales Government in Australia.enPublisher Copyright: © 2025 The AuthorsAbsorptance analysisSoilingSolar absorber coatingsSolar thermal energy conversion202510.1016/j.solener.2025.114035105017861689