Sol–Gel Synthesis of $\hbox{Au/Cu-TiO}_{2}$ Nanocomposite and Their Morphological and Optical Properties

A facile single-step method was adopted to synthesize gold-modified copper-doped titania nanocomposites. Physicochemical properties of the synthesized material were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy, photoluminescence (PL), and TEM-based techniques. Our characterizations show that the material consisted of anatase-phase qausi-spherical titania nanoparticles (NPs), with 3-4-nm gold particles anchored on titania surface. According to diffuse UV-visible spectroscopic analysis, gold-modified copper-doped titania shows enhanced absorption in the visible-light spectrum compared with copper-doped titania and pure titania. Furthermore, a decrease in PL emission intensity is observed, and this is due to decreased electron-hole recombination, which is an attribute desired for the enhancement of photocatalytic activity. Our present results highlight that these nanocomposites could be used as a photocatalyst for various applications in conjunction with visible solar radiation. The surface modifications make this material for many applications such as gas sensing and photodetection.