Smart protection of surfaces during day-night by a novel composite self-cleaning coating with catalytic memory

For the first time this work reports a new idea to develop a round-the-clock self-cleaning coating which was successfully applied to preserve cultural heritage and modern artifacts under sunlight illumination and at night. To fabricate this structure, namely, H2:TiO2/WO3@Pt, soft templating and hydrogen treatment approaches were selected to enhance the performance of TiO2/WO3 photocatalyst, together with the addition of Pt plasmonic nanoparticles. The coating can be photochemically charged in the presence of sacrificial electron donors and keep its stability, benefiting from the remained electrons stock for over 10 h to clean the surface from aggressive pollution also at night, in absence of light. This transparent heterostructure with high surface area, proper interfacial contacts in TiO2/WO3@Pt system, and extended visible light absorption resulting from the synergistic interactions of the composite system (TiO2, WO3, and Pt) presents an efficient self-cleaning performance. The smart coated surface could clean the substrate benefiting from 70% pollutants photodegradation after irradiation followed by dark storage (2 and 6 h, individually), and superhydrophilic properties were maintained for hours in the dark, thanks to oxygen vacancies resulted from hydrogen treatment.