Bismuth Doped PbO&lt;sub&gt;2&lt;/sub&gt; Coatings: Morphology and Electrocatalytic Properties

O Shmychkova,T Luk'Yanenko,A Velichenko

doi:10.13189/ujc.2013.010203

Abstract

Modified PbO2 anodes doped with bismuth were prepared by means of electrodeposition in methanesulfonate solutions. The influence of bismuth ions on morphological and electrocatalytic properties of obtained coatings was studied. Both XRD patterns and SEM micrographs demonstrated that incorporation of bismuth diminishes the size of crystal particles. It is shown, that oxygen overpotential on micromodified electrodes is sensibly higher than on non-modified PbO2-electrode. According to obtained results a hypothesis of a mechanism which include transfer of an increased number oxygen radical intermediates to Bi(III) to produce a sensible amount of Bi(IV) and Bi(V) that can participate in the O2 evolution process was proposed.

Highlights

Lead dioxide has attracted considerable attention owing to its use as a positive electrode in Red-Ox flow batteries, wastewater treatment, electrosynthesis, analytical sensors [1,2,3,4,5,6,7,8], due to a high overpotential for oxygen evolution, it is suitable for electrochemical processes at high anodic potentials such as ozone evolution [4,9,10,11,12]
In the present work we examine morphological and electrocatalytic properties of lead dioxide electrodeposited from methanesulfonate electrolytes containing bismuth ions
The scanning electron microscopy (SEM) microcraphs of undoped and doped PbO2 reported in Fig. 2 (a,b) show, in agreement with the XRD results, that Bi-PbO2 features a conspicuously different morphology with smaller size crystals

Summary

Introduction

Lead dioxide has attracted considerable attention owing to its use as a positive electrode in Red-Ox flow batteries, wastewater treatment, electrosynthesis, analytical sensors [1,2,3,4,5,6,7,8], due to a high overpotential for oxygen evolution, it is suitable for electrochemical processes at high anodic potentials such as ozone evolution [4,9,10,11,12]. The electrochemical properties of the electrodeposited PbO2 are strongly affected by doping species present in the deposition bath [5,12,13,14,15,16,17], especially such effects were observed when small amounts of ions like sulphate-, phosphate-, fluoride-, chloride-ions as well as iron, cobalt, arsenic and indium ions were present in the solution [13,14,15,18,19,20,21]. In the present work we examine morphological and electrocatalytic properties of lead dioxide electrodeposited from methanesulfonate electrolytes containing bismuth ions. PbO2-materials deposited from methanesulfonate electrolytes represent a considerable interest due to its high electrochemical stability and better mechanical properties in comparison with oxides, obtained from perchlorate, nitrate, acetate and alkaline solutions [9,16,17,22]. Despite a large number of publications [23,24,25,26,27,28], several issues on Bi effects remain to be explained to draw definitive conclusions about optimal conditions for deposition, correlation between type of deposit and its electrocatalytic reactivity

Methods

Results

Conclusion