Polycrystalline TiO2 particles synthesized via one-step rapid heating method as electrons transfer intermediate for Rhodamine B removal

Abstract

In this work, a one-step rapid heating method for the synthesis of polycrystalline TiO2 particles was demonstrated. By rapid and direct transfer of heat into the precursor solution, coupled with proper control of heating duration; polycrystalline TiO2 particles have been successfully synthesized in 45 min. TEM and XRD analyses demonstrated the polycrystalline nature of the TiO2 particles synthesized at 45 min composes of a mixture of 74% anatase phase (29.40 nm) and 26% brookite phase (21.07 nm). These polycrystalline TiO2 particles degraded 80% of Rhodamine B (RhB) after 60 min of visible light irradiation. The self-sensitization of RhB and crystal defects in polycrystalline TiO2 particles (electron donors), had produced more electrons in the conduction band of TiO2. These electrons then reduced the oxygen molecules to •O2− free radicals. Both electrons and •O2− free radicals were the main reactive species that degraded the RhB molecules as verified by scavenger tests. The promising photocatalytic performance together with the simple and low cost synthesis method, have provided a feasible alternative in the development of visible light active photocatalyst for organic dye removal.