Catalytic Degradation Of Methyl Orange Research Articles

Preparation of Pt–Fe 2O 3 nano-electrode array on gold nano-wires and its application to the catalytic degradation of methyl orange

A novel method to prepare Pt–Fe 2O 3 nanoparticles (NPs) for organic matter degradation was developed in this study. The main feature of this study was to prepare a gold nano-wire substrate through integration of holographic lithography, microfabrication techniques and electrochemical co-deposition methods. The catalytic gold nano-wire substrate was used for the electrochemical co-deposition of Pt–Fe 2O 3 NPs. The surface morphology of the prepared Pt–Fe 2O 3 NPs was characterized by scanning electron microscope imaging. It was found that the Pt–Fe 2O 3 NPs formed upon the Au nano-wire surface and in the gap between the adjacent nanowires. The X-ray photoelectron spectrum analysis showed that Pt and Fe 2O 3 were the main chemical components of the NPs. The Pt–Fe 2O 3 NPs exhibited a high electrochemical catalytic activity toward methyl orange (MO) degradation under neutral condition, with 93.5% of MO degraded within 6 h at the voltage of −1.5 V. It demonstrated a high potential to be used for degradation of azo dyes under neutral conditions without the addition of any chemical agent and causing any further pollution problem.

Preparation, electrocatalytic and photocatalytic performances of nanoscaled CuO/Co3O4 composite oxides

Cu-Co composite oxides with different Cu/Co atomic ratios were prepared by the calcination of the precursors synthesized via a co-precipitation method. The samples were characterized by XRD, SEM and TEM, respectively. The XRD analysis revealed that only spinel structure of Cu-Co composite oxide was confirmed with lower Cu/Co ratio (<1:2). The sizes and morphologies of samples are controlled significantly by the Cu/Co atomic ratios. The electrocatalytic activity for p-nitrophenol reduction in a basic solution with the samples decorated on glassy carbon (GC) electrodes was tested by cyclic voltammetry (CV). The results showed that the sample with Cu/Co ratio of 2:8 exhibited the highest catalytic activity for p-nitrophenol reduction. The photocatalytic performances of the samples for the degradation of methyl orange under irradiation of visible light were investigated. The samples with Cu/Co ratios from 5:5 to 10:0 all showed better photocatalytic activities for methyl orange degradation, but the sample with Cu/Co ratio of 9:1 exhibited much higher catalytic activity. The catalyst with Cu/Co ratio of 9:1 also exhibited excellent repeatability for the catalytic degradation of methyl orange.

Visible light active TiO2 films prepared by electron beam deposition of noble metals

Abstract TiO 2 films prepared by sol–gel method were modified by electron beam deposition of noble metals (Pt, Pd, and Ag). Effects of noble metals on the chemical and surface characteristics of the films were studied using XPS, TEM and UV–Vis spectroscopy techniques. Photocatalytic activity of modified TiO 2 films was evaluated by studying the degradation of methyl orange dye solution under visible light UV irradiation. The result of TEM reveals that most of the surface area of TiO 2 is covered by tiny particles of noble metals with diameter less than 1 nm. Broad red shift of UV–Visible absorption band of modified photocatalysts was observed. The catalytic degradation of methyl orange in aqueous solutions under visible light illumination demonstrates a significant enhancement of photocatalytic activity of these films compared with the un-loaded films. The photocatalytic efficiency of modified TiO 2 films by this method is affected by the concentration of impregnating solution.