Highly Efficient Visible-Light-Driven Photocatalysis of Rose Bengal Dye and Hydrogen Production Using Ag@Cu/TiO2 Ternary Nanocomposites

Abstract

In this work, an Ag@Cu/TiO2 ternary nanocomposite was synthesized by a simple chemical methodology and subsequently studied for the photocatalytic degradation of rose bengal (RB) dye under visible light as well as its hydrogen production. The shape, size and topographical analysis by scanning and transmission electron microscopy revealed that all the constituents are well intercalated and are in the nano range. The energy dispersive X-ray analysis of the Ag@Cu/TiO2 showed the presence of Ti, O, Cu and Ag and the absence of any other impurities, while the mapping analysis showed their uniform distribution. The X-ray photon spectroscopy also showed successful interaction between the components. Furthermore, the changes in the chemical state of Ti2p were examined. The band gap of Ag@Cu/TiO2 using the Tauc plot relations was found to be the lowest at 2.86 eV in comparison to pure TiO2 (3.28 eV), binary Ag/TiO2 (3.13 eV) and Cu/TiO2 (3.00 eV). The Ag@Cu/TiO2 displayed the lowest photoluminescence intensity, suggesting the highest degradation efficiency and lowest recombination rate. The application of Ag@Cu/TiO2 toward the photocatalytic degradation of RB dye exhibited a degradation rate of ~81.07%, which exceeds the efficiency of pure TiO2 by 3.31 times. Apart from this, the hydrogen production of Ag@Cu/TiO2 was found to be 17.1 μmol h−1 g−1, suggesting that copper and silver synergistically contributed, thereby resulting in the increased hydrogen production of pure TiO2.