TiO₂ quantum dots for the photocatalytic degradation of indigo carmine dye

In this work, we report the synthesis of TiO₂ quantum dots using a simple sol–gel, template free method. The synthesized quantum dots were further studied for their crystalline, morphological, chemical and photo-luminescent properties by using various techniques. The detailed studies revealed that the synthesized TiO₂ quantum dots possess well-crystalline pure anatase phase and exhibited good photo-luminescent properties. Further, the catalytic behavior of synthesized quantum dots was monitored by photo-catalytic degradation of aqueous solution of Indigo carmine dye under UV-light irradiation. The reaction conditions were varied so as to optimize catalyst dose, initial dye concentration, pH and reaction temperature. It was found that reaction was facilitated with optimum catalyst dose of 0.75 g/L, low dye concentrations, acidic pH and ambient reaction temperature condition of 25 °C. The reaction kinetic was studied and it was found that the indigo carmine dye photo catalytic degradation followed pseudo first order reaction kinetics with rate constant, k of 0.023 min⁻¹. - Highlights: • Synthesis of well-crystalline TiO₂ quantum dots. • Excellent morphological, crystalline and photoluminescent properties. • Efficient photocatalyst for the photocatalytic degradation of indigo carmine dye.