Electrocatalysis of Anodic Oxygen‐Transfer Reactions: Effect of Groups III A and VA Metal Oxides in Electrodeposited β‐Lead Dioxide Electrodes in Acidic Media

Abstract

The heterogeneous rate constant for the anodic oxidation of Mn(II) at PbO2-based mixed oxide electrodes in 1.0M HC104 was determined as a function of high doping levels by the oxides of Group IIIA and VA metals. Electrodes were prepared by electrodeposition from solutions containing Pb -~+ and the doping metal ions in 1.0M HC104. Doping with the Group IIIA metal oxides results in a slight decrease in the rate constant for Mn 2+ oxidation; however, doping with the Group VA metal oxides results in significant electrocatalysis of the anodic oxygen transfer reaction, as compared to a pure ~-PbO2 electrode. The rate constant at the mixed oxide deposited from a solution of 1.0 mM Bi~+/1.0 mM Pb 2+ was at least 25 times greater than for pure ~-PbO2, becoming virtually mass-transfer limited at the mixed oxide electrode to rotation rates of 3600 rev min-'. (mA -I ) 1.5 D m J J ~J f

Electrodeposited lead dioxide coatings

“…Lead dioxide anodes have also been used for the production of strong oxidising agents such as dichromate, 78,[111][112][113][166][167][168] manganese (III) 109,114,119,169,170 and cerium(IV). [169][170][171][172] Most commonly, these processes are used to regenerate the spent oxidising agent from the oxidation of organic compounds (e.g.…”

Environmental Electrochemistry

“…The publications dealing with anodic destruction of organics at metal-oxide electrodes can effectively be divided into two main groups: (1) those of Johnson and others [15][16][17][18][19][20][21][22][23], who concentrate on the modified PbO 2 electrode system; (2) those of Comninellis and others [24][25][26][27][28][29][30], who deal with the modified SnO 2 system. The reason for using high-oxygen overvoltage anodes is to drive the electrochemical reaction into a potential range where oxidation of the organics is possible (during galvanostatic anodic treatment); correspondingly, the extent of parallel oxygen evolution decreases during constant potential treatment.…”

“…The reason for using high-oxygen overvoltage anodes is to drive the electrochemical reaction into a potential range where oxidation of the organics is possible (during galvanostatic anodic treatment); correspondingly, the extent of parallel oxygen evolution decreases during constant potential treatment. In the extensive PbO 2 work of Johnson et al [15][16][17][18][19][20][21], the central idea is that incorporation of an alter-valent ion such as Bi(5+) into the oxide lattice greatly facilitates oxygen transfer to the solution species (R) to be treated. [When reading these papers, one should be aware that there were three procedures for doping the films with Bi: (1) anodic adsorption as Bi(5+) ad atoms onto β-PbO 2 before the oxygen-transfer experiment; (2) having Bi (3+) in the solution during the oxygentransfer experiment at the β-PbO 2 electrode; and (3) formation of the anode coating by deposition onto substrates such as gold from Bi(3+)/Pb(2+) solutions of varying ratios prior to the oxygen-transfer experiment.…”

Formation and growth of PbO2 inside TiO2 nanotubes for environmental applications

“…Therefore, other practical options for the preparation of PbO 2 anodes need to be considered. Different kinds of PbO 2 have been prepared: pure metal oxide [24][25][26][27], mixed with other metallic oxides [29], or doped with different ionic species [16,[30][31][32][33][34]. Often, PbO 2 is deposited on a metallic substrate such as Ti [35,36], Au [37,38] or Pt [39,40] in order to improve its mechanical properties and to preserve its catalytic properties [28,[41][42][43].…”