Review Paper
Revisiting why DBDs can generate O3 against the thermodynamic limit
Hyun-Ha Kim 1, *,
Ayman A Abdelaziz1, 2,
Yoshiyuki Teramoto1,
Tomohiro Nozaki3,
Dae-Young Kim3,
Ronny Brandenburg4,
Milko Schiorlin
* The author to whom correspondence should be addressed.
1 National Institute of Advanced Industrial Science and Technology (AIST), Environmental Management Research Institute, Tsukuba, Japan
2 Assuit University, Assuit, Egypt
3 Tokyo Institute of Technology, Tokyo, Japan
4 Leibniz Institute for Plasma and Technology, Greifswald, Germany
5 Comenius University, Bratislava, Slovakia
6 Korea Institute of Machinery and Materials (KIMM), Daejeon, Korea
7 Toyohashi University of Technology, Toyohashi, Japan
Abstract
This short review provides a general perspective on ozone formation and includes a brief history of the great German inventor Werner von Siemens, who invented the prototype ozonizer. The main structure of Siemens ozonizer still serves as the de facto model in large-scale applications. This review places particular focus on the thermodynamic aspect of ozone formation in dielectric barrier discharge (DBD), which is fundamental but puzzling to newcomers in plasma chemistry. As is often mentioned in the chemistry of nonthemal plasmas, non-equilibrium reactions initiated by highenergy electrons allow for the dissociation of oxygen molecules at ambient temperature, even though it is a highly endothermic process. Once atomic oxygen is formed, it spontaneously combines with oxygen molecules to form ozone with a heat release. This elaborate coupling of the non-equilibrium with equilibrium processes, as well as exothermic and endothermic processes, makes the DBD reactor an efficient and effective method for O3 formation against the thermodynamic limits. Understanding the interplay of these elementary processes in the DBD reactor is essential in comprehending how ozone is generated, and it sheds light on further development. This review aims to provide valuable insights into the thermodynamic mechanisms behind ozone formation and some noticeable applications of ozone, assisting newcomers in plasma chemistry to grasp the underlying principles of this crucial process.
Keywords - Ozonizer, dielectric barrier discharge (DBD), ozone, thermodynamic limit, non-equilibrium.