Effect of nanotube diameter on the photocatalytic activity of bimetallic AgAu nanoparticles grafted 1D-TiO2 nanotubes

Abstract

One-dimensional (1D) titanium dioxide (TiO2) nanostructures have enormous attention for next-generation renewal energy resources. In reference to that, present work reports the effect of different voltages (40 V and 60 V) on the structural and morphological properties of 1D-TiO2 nanotubes (TONTs) and their hybrids by grafting of bimetallic nanoparticles (BiMNPs) of AgAu. The growth at different voltages affects the morphology and diameters of TONTs as imaged using field emission scanning electron microscopy (FESEM). The variation in anodization voltage from 40 to 60 V increases the diameter of TONTs that offers a larger active surface area of TONTs. It is further revealed that the crystallinity and crystallite size of TONTs is increased after increasing the anodization voltage. Furthermore, TONTs are integrated with AgAu BiMNPs to form the hybrid structures. The AgAu-TONT hybrid forms a modified interface and induces less compressive strains that improve the charge separation at the interface and hence improve the electronic structure, as investigated by X-ray photoelectron spectroscopy (XPS) and X-ray Diffraction (XRD). On further exploring the 1D-TONTs and AgAu-TONTs for photocatalytic studies, it is observed that the photocatalytic activity of AgAu-TONTs is better than TONTs-40 V and TONTs-60 V. The improved photocatalytic activity in the AgAu-TONTs is due to the large surface area, charge carrier generation, and lesser compressive strain present at the interface.