Some positive effects of introducing Pt4+ and Fe3+ to the MnMo-oxide anode deposited on IrO2/Ti substrate for best oxygen evolution efficiency during electrolysis in 0.5 M NaCl solution

• Main Authors: R.M. Abou Shahba, E.M. Attia, N.M. Deiab
• Format: Article
• Language: English
• Published: Elsevier 2013-06-01
• Series: Egyptian Journal of Petroleum
• Subjects: NaCl electrolysis; Electro-deposition; Oxygen evolution efficiency
• Online Access: http://www.sciencedirect.com/science/article/pii/S1110062112000475

NaCl solution (0.5 M) of pH 2 was electrolyzed at 1000 Am−2 at room temperature. Addition of Pt4+ and Fe3+ to the prepared MnMo-oxide anode deposited on IrO2/Ti substrate, significantly improves the performance of anode for the oxygen evolution reaction (OER) during NaCl electrolysis. After 2000 h of electrolysis, the oxygen evolution efficiency (OEE) is in the order of MnMoPt-oxide > MnMoFe-oxide > MnMo-oxide anodes with 100%, 99%, and 93.2% OEE, respectively. The loss in weight of MnMo-oxide is reduced from about 13% to 3.2% and 0.0% by addition of iron and platinum cations, to the deposition electrolyte. The mean average grain size of MnO2, MnMo-, MnMoFe- and MnMoPt-oxide deposits prepared in electrolytes of pH 0.0 are in the range of 25.5, 16.22, 13.5 ∼ 16.5 and 13 ∼ 17.5 nm, respectively. The physicochemical properties of the deposits were characterized using X-ray diffraction spectroscopy (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and electrochemical techniques. EDX analysis illustrates that IrO2/Ti is stable during the deposition process and behaves only as conductive substrate. SEM illustrates that, all elements constituting MnMoPt- and MnMoFe-oxide deposits are homogeneously distributed in the oxide surface.