Black anatase-TiO₂ electrodes for sun-activated photocatalytic degradation of organic water contaminants

This study presents the synthesis of black anatase in air and its use for the fabrication of a reusable electrode for the photocatalytic degradation of Rhodamine B (RhB) under visible-light. Characterization techniques such as X-ray diffraction, Raman spectroscopy, and Transmission Electron Microscopy (TEM) were used to analyze the properties of black anatase. The immobilization of black TiO₂ on a glass substrate eliminates the need for post-treatment recovery of the photocatalyst. Enhancement of photocatalytic activity was achieved by depositing a 4 nm platinum layer on the black anatase TiO₂ electrode. Activation of the photocatalytic process (λ ≥ 400 nm) was conducted with a solar simulator, and the degradation of RhB was monitored through visible absorption and time-resolved fluorescence spectroscopy, revealing degradation efficiencies of 94 % and 89 % after 40 and 60 min, respectively. These results are attributed to the elevated levels of oxygen vacancies and the Schottky barrier formed between the platinum layer and black anatase. The methodology's simplicity and the significant photocatalytic efficiency suggest potential for widespread application in solar-driven photocatalytic degradation.