Electrochemical redox processes involving soluble cerium species

Abstract

Anodic oxidation of cerous ions and cathodic reduction of ceric ions, in aqueous acidic solutions, play an important role in electrochemical processes at laboratory and industrial scale. Ceric ions, which have been used for oxidation of organic wastes and off-gases in environmental treatment, are a wellestablished oxidant for indirect organic synthesis and specialised cleaning processes, including oxide film removal from tanks and process pipework in nuclear decontamination. They also provide a classical reagent for chemical analysis in the laboratory. The reversible oxidation of cerous ions is an important reaction in the positive compartment of various redox flow batteries during charge and discharge cycling. A knowledge of the thermodynamics and kinetics of the redox reaction is critical to an understanding of the role of cerium redox species in these applications. Suitable choices of electrode material (metal or ceramic; coated or uncoated), geometry/structure (2-or 3-dimensional) and electrolyte flow conditions (hence an acceptable mass transport rate) are critical to achieving effective electrocatalysis, a high performance and a long lifetime. This review considers the electrochemistry of soluble cerium species and their diverse uses in electrochemical technology, especially for redox flow batteries and mediated electrochemical oxidation.

Pressure drop through platinized titanium porous electrodes for cerium‐based redox flow batteries

“…Three‐dimensional (3‐D) platinized titanium (Pt/Ti) structures are the preferred electrodes for the conversion of cerium ions in electrochemical flow reactors . Following its use in mediated electrosynthesis, nuclear decommissioning, and disposal of hazardous organics, the Ce(III)/Ce(IV) redox couple has received attention in the field of electrochemical energy storage.…”

Mass transport and active area of porous Pt/Ti electrodes for the Zn-Ce redox flow battery determined from limiting current measurements

“…The second and third electroplating procedures were performed galvanostatically at 100 mA cm -2 until the consumption of dissolved Pt was verified. The distribution and coverage of platinum in the Pt/Ti micromesh and Pt/Ti felt electrodes is subject of discussion in a related work [42].…”

“…Such an approach allows laboratory and pilot-scale flow cells as well as different electrode materials (including carbon felt under different degrees of compression in all-V RFBs) to be compared. As discussed in a recent review [27], the performance of Pt/Ti electrodes is also important to diverse industrial electrochemical processes reliant on anodic generation of Ce(IV). Electrode optimization is desirable to increase space-time yield and minimize electrolyte material, electrolytic cell potential and energy consumption.…”

Editors' Choice—Electrodeposition of Platinum on Titanium Felt in a Rectangular Channel Flow Cell

“…Ce(III) − e − → ← Ce(IV) E o = +1.74 V vs SHE [1] The manufacture of Pt/Ti planar and mesh electrodes often involves the repeated immersion of titanium sheets in a solution followed by the thermal decomposition of the precursor in a furnace. 16 Dimensionally stable anodes (DSA) for the chlor-alkali process can be manufactured on a large scale in this fashion while industrial Pt/Ti electrodes are often produced by electrodeposition of platinum on titanium after the application of a noble metal oxide inter-coating, typically IrO x .…”

“…The electrochemical redox of cerium ions in aqueous methanesulfonic acid (MSA) for industrial 1 and energy storage 2 applications requires porous, flow-through platinized titanium (Pt/Ti) electrodes. These electrodes encompass high catalytic activity, corrosion resistance and low cost (in comparison to bulk platinum electrodes).…”