Synthesis of SnO2-Ag nanocomposites via thermal decomposition method and their application for catalytic reduction of 4-nitrophenol and photocatalytic degradation of congo red

Abstract

The discharge of untreated effluents containing toxic chemicals such as dyes into an aquatic environment disrupts ecological balance. Metal oxide-based nanocomposites can be used as photocatalyst to effectively remove organic dyes from waste water. In the present study, using a novel thermal decomposition approach, synthesis of SnO2-Ag nanocomposites has been achieved using tin chloride pentahydrate and silver salicylate ([Ag(HSal)]) as precursors. The particle size of Ag in the SnO2-Ag nanocomposites could be controlled by changing the amount of [Ag(HSal)] used during the synthesis. The presence of SnO2 and Ag nanoparticles in the SnO2-Ag nanocomposites was confirmed using powder X-ray diffraction (XRD). The purity of SnO2-Ag nanocomposites was proved by Fourier transform infrared (FT-IR) spectroscopy. The presence of Sn4+, Ago, surface hydroxyls and lattice oxygen was confirmed by XPS studies. The SnO2-Ag nanocomposites absorb in UV and visible regions. The SnO2-Ag nanocomposites perform as better catalyst for the photocatalytic degradation of congo red (CR) compared to the constituents. The nanocomposites show faster kinetics (within 30 minutes) as compared to the previously reported SnO2 based systems in the literature. The SnO2-Ag nanocomposites were also explored for catalytic degradation of 4-nitrophenol (4-NP) in an aqueous solution.