Photocatalytic reduction of methylene blue induced by a commercial titanium precursor in homogeneous phase

Abstract

This work evaluates the photocatalytic activity of titanium(IV) bis(ammonium lactate) dihydroxide (TiBALDH), an inexpensive commercial precursor and potential alternative to TiO2 nanostructures in heterogeneous photocatalysis, to reduce methylene blue in an aqueous medium. Results show that the titanium precursor without further preparation (other than dilution) shows a high activity for degrading the dye within a few seconds, even at 0.5 mM. The photocatalytic activity is dependent on the concentration, type of radiation, and pH, suggesting the presence of two main concentration-dependent photoreactive species, most likely oxoclusters. Additionally, the homogeneous system is not limited by adsorption processes, as is the case in heterogeneous systems with TiO2 nanoparticles, and it offers greater reusability while avoiding catalyst poisoning. This approach shows the potential for efficient advanced oxidation processes in homogeneous solutions by exploiting the chemical equilibrium of titanium lactate complexes in aqueous solution.