Improving photocatalytic Rhodamine B degrading activity with Pt quantum dots on TiO2 nanotube arrays

Well-dispersed Pt quantum dots (QDs) with an average diameter of 2 nm were homogeneously decorated on TiO2 nanotube arrays (TNTAs) by a modified photo irradiation-reduction method. The effect of the precursor concentration between 0.3 mM and 2.0 mM on the decorated Pt QD content was investigated. The synthesized nanostructures with different Pt QD contents were characterized by XRD, SEM, TEM, XPS, UV-vis and PL. The Pt QDs, acting as electron sinks, reduced the recombination of electrons and holes and extended their lifetime, leading to a greatly enhanced photocatalytic performance. In a 1.0 mM concentration, the fabricated nanocomposite with excellent durability exhibited favorable photocurrent density and efficiency of degrading Rhodamine B. According to EPR analysis, the corresponding mechanism of the UV-driven photocatalytic process is proposed. Furthermore, the nanocomposite is easier to be recycled compared to the powder catalysts.