Preparation of Cu2O Nanoparticles as a Catalyst in Photocatalyst Activity Using a Simple Electrodeposition Route

In order to obtain inexpensive and effective application of catalyst for photodegradation, Cu2O powder was prepared by the simple and inexpensive electrodeposition method using surfactants such as glycerin (GLY), polyvinyl alcohol (PVA), poly(N-vinylpyrrolidone) (PVP) that helped the growth and nucleation of suspended particles. These particles were distinguished by atomic force microscopy (AFM), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). Diameter size of these obtained particles was found to reach to about 40 nm. In order to demonstrate the photodegradation efficiency of the copper oxide in the removal of organic malachite green oxalate (MG) dye, the catalyst was used both in calcination at 300 ℃ and without calcination. Parameters such as the amount of catalyst, the concentration of dye, the pH of dye sol, and the temperature were calculated. Pseudo first order reactions according to Langmuir-Hinshelwood kinetics could be obtained from the result of photocatalytic reactions. Parameters such as energy activation (Ea), enthalpy of activation (ΔH0), entropy of activation (ΔS0) and free energy of activation (ΔG0) were calculated. The activation energy was equal to 11.719 ± 1 and 11.083 ± 1 kJ/mol for MG dye in the presence of Cu2O nanoparticles in both two cases of calcination and without calcination respectively

Cyclic Voltammetry Study for MnO2 Nanoparticles Modified Carbon Paste Electrode

An electrical method was prepared for the measurement of Mn with trace amount in drugs and for the assessment of a sensitive method in comparison with spectrometric and atomic analyzer by a new carbon paste electrode modified with MnO2 nanoparticles. The method was used to study the electro oxidation of manganese ions in solution by cyclic voltammetry (CV) method. The modified electrode displayed strong resolving function for the overlapping voltammetric response of Mn-ion into one well-defined peak. The potential difference between Epa and Epc was > 200 mV; this range referred to the quise-reversible mechanism. The kinetic of electrode was studied at the temperature range from 15 – 35 ℃; the data of voltamograms showed the increase of temperature caused increase of negative shift, which suggested the diffusion electron transferred in the redox process of Mn-ion oxidation. Diffusion coefficient was calculated from the Randles-Sevcik equation and was equal to 1×10-7; the rate constant K was equal to 5.3×10-5; the peak current of Mn-ion increased linearly with its concentration at the range of 0.5 – 4.5 ppm

Zinc Metal at a New ZnO Nanoparticles Modified Carbon Paste Electrode: A Cyclic Voltammetric Study

A new carbon paste electrode modified with ZnO nanoparticles was prepared and used to study the electro oxidation of zinc ions in solution by cyclic voltammetry (CV) method. The modified electrode displayed strong resolving function for the overlapping voltammetric response of zinc into one well-defined peak. The potential difference between Epa and Epc was > 200 mV, the range of which referred to the quasi-reversible mechanism. The kinetic of electrode was studied in the range of temperature 15-30 ℃. The data of voltamograms showed the negative shift increased with increase of temperature, the result of which referred to the diffusion electron transfer in redox process of zinc oxidation. Diffusion coffining was calculated from Sevcik-Randles equation and thus equaled to 1.01×10-7. The rate constant was equal to 5.2×10-8 and 3.3×10-8 for oxidation and redaction respectively. And the peak current of zinc increased linearly with its concentration in the range of 2.0-20.0 ppm