Defect‐Induced Self‐Cleaning Solar Absorber with Full‐Spectrum Light Absorption for Efficient Dye Wastewater Purification

Abstract

Solar steam generation is considered a promising approach to provide the solution for water scarcity. To solve the problem of organic pollutions’ enrichment on traditional solar absorbers, herein, a self‐cleaning absorber, which consists of CsXWO3 nanorods‐anchored hydrogenated TiO2−X nanowires based on a flexible Ti mesh (H‐TiO2−X/CsXWO3), is proposed. The well‐designed H‐TiO2−X nanowires grown on Ti mesh contain a rational concentration ratio of surface oxygen vacancies (OV) to bulk OV, and the introduced W5+ and OV in CsXWO3 nanorods are also demonstrated. The defects in H‐TiO2−X/CsXWO3 endow it with a superior photocatalytic activity and light absorption in the full spectrum. Importantly, the enrichment of organic molecules, both on the surface of solar absorbers and in bulk water is carefully studied during solar steam generation. Compared with the spatially separated evaporation device without photocatalytic activity, the multifunctional H‐TiO2−X/CsXWO3 composite can not only accomplish a high evaporation rate of 1.46 kg m−2 h−1, but also prevent the surface enrichment of dye after continuous 12 h evaporation or after 20 cycle tests. Integrating photocatalysis into solar‐driven water evaporation optimizes the performance and broadens the application field.