Facile synthesis of IrO$_{2}$ nanoclusters and their application as catalysts in the degradation of azo dyes

摘要

A robust synthesis of iridium oxide (IrO$_{2})$ nanoclusters using methanol as a reducing agent via the chemical reduction method is reported in this article. Polyvinylpyrrolidone (PVP) and polyoxyethylene(23) lauryl ether (POLE) were used as stabilizers. The formation of IrO$_{2}$ nanoclusters was confirmed by the appearance of new absorption peak at 230 nm in UV-vis spectra. XRD and TEM were used to determine the degree of crystallinity and size of nanoclusters, respectively. Further characterization studies were carried out by FT-IR spectroscopy to investigate the coordination between IrO$_{2}$ nanoclusters and stabilizers. The size of the nanoclusters was found to be a factor of the ratio of solvent to reductant and precursor to stabilizer. It was found that PVP-stabilized IrO$_{2}$ nanoclusters are smaller in size with narrow distribution in contrast to POLE-stabilized IrO$_{2}$ nanoclusters. The catalytic activity of these nanoclusters was examined in the degradation of some azo dyes, acid orange 10 (AO 10), acid red 14 (AR 14), and acid red 26 (AR 26), in aqueous medium. PVP-stabilized IrO$_{2}$ nanoclusters are catalytically more efficient than POLE-stabilized IrO$_{2}$ nanoclusters, which was supported by the calculation of turnover frequencies. Thus, IrO$_{2}$ nanoclusters are expected to play an imperative role in the field of catalysis and environmental remediation.