Sub-nm titanium dioxide clusters: efficient photocatalysts for clean SOx conversion under visible light irradiation

In this study, the hydrolysis of TiCl4 was utilized to synthesize titanium dioxide clusters (TiO2 NCs) at a sub-nanometer scale. Precise control over the synthesis process resulted in the production of stable particles with well-defined size distributions. These TiO2 NCs were specifically developed to facilitate the conversion of SOx into organo-sulfonic acid derivatives under visible light irradiation. Various characterization techniques such as TEM, EDX, XRD, UV-Vis-DRS, Raman, and FTIR were employed to analyze the formed photocatalysts, including TiO2 nanoparticles (NPs) and NCs. The efficiency of catalytic SOx removal depended significantly on the particle size and surface area of the nanocatalysts, as well as the presence of thymol or naphthol (1,2). These materials (1,2) proved to be highly effective in removing SOx from flue gas under ambient conditions, specifically at room temperature. The conversion of thymol or naphthol involved a combination of adsorption and catalytic oxidation-reduction reactions. This photocatalytic approach for SOx conversion offers several advantages, including high performance, elimination of the need for high temperature or pressure, and rapid catalytic removal within a short reaction time of 10 min. TiO2 NCs demonstrate high efficiency in SOx removal, offering a promising solution for pollution control. Unlike some other methods, TiO2 nanoparticles can be potentially regenerated and reused, making them a more sustainable approach.