Electrode characteristics for ozone production: a case study using undoped and doped PbO2 on porous platinised titanium substrates

Abstract

The primary aim of this paper is the study of the stability and electrochemical activity of PbO 2 electrodeposited onto porous, platinised Ti substrates. The evolution of O 2 from H 2 O oxidation, on as-prepared electrodes, results in the opening of large pores that effectively work as gas channels for removing O 2 generated inside the porous structure, thus favouring the reaction penetration deeper into the pores. A serious problem that limits the utilisation of the internal pore surface is the instability of PbO 2 towards corrosion at high positive potentials or currents. Occlusion of pores by corrosion products is clearly demonstrated by SEM analysis of electrodes after operation as O 2 evolving anodes. Doping PbO 2 with Fe 3+ and Co 2+ yields anodes that resist corrosion up to relatively high anodic potentials/currents; this extends the anode lifetime by decreasing amorphisation of the electrocatalyst and its partial detachment caused by a high pressure of O 2 formed inside the pores during water electrolysis. This is an important result since stability of electrodes is as important as their electrochemical activity for practical applications.In the domain of high positive potentials, PbO 2 doping by Fe 3+ and Co 2+ results in a significant increase of the current efficiency of ozone generation. The magnitude of the observed increase depends on the individual characteristics of the doping cation and of the electrolyte employed. Possible involvement of higher oxidation states of cobalt and iron in the reaction mechanism is discussed on the basis of published literature.

Tailoring the d‐Band Centers of Perovskite Oxides for Electrochemical Ozone Production

“…Herein, we attempt to find active and durable ABO 3 ‐type perovskite oxides electrocatalysts by replacing the A‐site with lanthanum elements, whereas Co is locked as B‐site due to its high electrical conductivity and loosely bonded d electrons [37,38] . As previously studies reported, doping PbO 2 with Co atom resulted in a significant increase of ozone generation than pure PbO 2 [39,40] . In general, appropriate valence state of Co can promote *O generation and inhibit the desorption of O 2 [37,41] .…”

“…[37,38] As previously studies reported, doping PbO 2 with Co atom resulted in a significant increase of ozone generation than pure PbO 2 . [39,40] In general, appropriate valence state of Co can promote *O generation and inhibit the desorption of O 2 . [37,41] Therefore, how to change the valence state of Co by changing A element is significant to improve the current efficiency of ozone generation.…”

Fabrication and Enhanced Electrocatalytic Activity of Three-Dimensional Sphere-Stacking PbO2Coatings Based on TiO2Nanotube Arrays Substrate for the Electrochemical Oxidation of Organic Pollutants

“…The EIS simulation results are showed in Table II. In the equivalent circuit, R s is the solution resistance, R ct and the constant phase element (CPE) are associated with charge transfer and the real double-layer capacitance, 42 respectively, and the W represents the Warburg impedance. It was found from Table II that the R s , R ct and W values of 3D-sphere PbO 2 electrode were less than that of flat-PbO 2 , which suggested that better electrical conductivity of 3D-sphere PbO 2 electrode.…”

Preparation and Photoelectrocatalytic Performance of Ti/PbO2 Electrodes Modified with Ti4O7

“…Whether or no, the activity and stability of obtained Ti/PbO 2 still needs to be improved for its practical application. To further improve its electrocatalytic activity and stability, many researchers have done a great deal of research on the modification of PbO 2 electrode, including doping of various ions (F − , Bi 3+ , Ce 3+ , Ru 3+ , Ag + , Co 2+ , Sn 4+ and Fe 3+ ) and incorporation of additives in PbO 2 coatings (TiO 2 , CeO 2 , polytetrafluoroethylene (PTFE), polyeth‐ ylene glycol (PEG), carbon nanotube (CNT)). Based on previous reports, it is found that the reasonable modification is beneficial for improving of electrocatalytic performance of PbO 2 electrode.…”