Application of ultrasound in electrochemistry. An overview of mechanisms and design of experimental arrangement

• Published in: Ultrasonics 2011-02, Vol.51 (2), p.202-209
• Main Author: Klima, J.
• Format: Article
• Language: English
• Subjects: Acoustic streaming; Acoustics; Chemistry; Exact sciences and technology; Fundamental areas of phenomenology (including applications); General and physical chemistry; Mechanism of sonochemical effect; Microjets; Nonlinear acoustics, macrosonics; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Physics; Sono-electrochemical cell design; Sonoelectrochemistry; Ultrasonic chemistry; Underwater sound
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2010.08.004

An overview of possible mechanisms by which sonication can influence electrochemical processes is given. Four mechanisms are discussed: – acoustic streaming; – microstreaming and turbulence due to cavitation; – formation of microjets in the course of collapse of cavitation bubble; – shock waves; and possible effects are illustrated on several examples. The most effective process is formation of microjets, which can not only decrease diffusion layer thickness under 1 μm, but also activate (depassivate) electrode surface. Design of experimental arrangement with maximum participation of microjets is proposed. Two approaches are proposed: – focusing of ultrasound on the working electrode and reduction of energy losses by over-pressure; – “tuning” the reactor to obtain resonance, i.e. formation of stationary waves by activating reactor in its resonant mode.