The effects of power ultrasound on electrochemical systems and important electrochemical parameters were originally demonstrated by Moriguchi[1] and then by Schmid and Ehert [2][3] when the researchers investigated the influence of ultrasound on concentration polarisation, metal passivation and the production of electrolytic gases in aqueous solutions.
In 1959, Penn et al.[5] demonstrated that sonication had a great effect on the electrode surface activity and electroanalyte species concentration profile throughout the solution.
In the early 1960s, the electrochemist Allen J. Bard[6] showed in controlled potential coulometry experiments that ultrasound significantly enhances mass transport of electrochemical species from the bulk solution to the electroactive surface.
In the range of ultrasonic frequencies [20 kHz – 2 MHz], ultrasound has been applied to many electrochemical systems, processes and areas of electrochemistry (to name but a few: electroplating, electrodeposition, electropolymerisation, electrocoagulation, organic electrosynthesis, materials electrochemistry, environmental electrochemistry, electroanalytical chemistry, hydrogen energy and fuel cell technology) both in academia and industry,[7] as this technology offers several benefits over traditional technologies.
To date, over 3,500 publications[10] inc. patents, technical, research and review articles have been written on the subject with the vast majority being published post-1990 after a review paper from Mason et al.[11] entitled 'Sonoelectrochemistry' highlighting the extraordinary effects of sonication on enhancing mass transport, aiding solution degassing, improving electrode surface cleaning, producing radical species (via sonolysis) and increasing electrochemical products and yields.