Silver-Based Colorant on Self-Supported Nanoporous Titanium for Reversible Surface Printing

Color-switching materials have broad applications in diverse fields. Integrating these materials onto metal surfaces unlocks responsive optical functionalities, expanding the potential of traditional metals. In this study, we present a versatile approach to developing a robust color-switching system on titanium surfaces by integrating a self-supported nanoporous TiO2 framework with silver-based colorants. The reversible color-switching process is driven by ultraviolet (UV) light-induced reduction of silver ions to silver nanoparticles, followed by oxidation with hydrogen peroxide to restore the original appearance. This system leverages the high surface area and stability of nanoporous TiO2 to achieve a uniform silver ion loading and efficient photocatalytic reduction/H2O2 oxidation. Our system demonstrates rapid, reversible, and tunable color changes with excellent durability over multiple cycles. These properties make the material a promising candidate for applications including reversible surface printing and other applications where responsive or adaptive metal surfaces are required.