Ozone Synthesis Based on Dielectric Barrier Discharge Coupled Catalyst: Research Status and Future Perspectives.

Efficient ozone synthesis has always been the pursuit of ozone workers and the foundation for the industrial application of ozone reactors. Recently, with continuous breakthroughs in materials and catalyst research, as well as the rapid development of advanced characterization technologies, introducing catalysts into dielectric barrier discharge (DBD) to build a DBD-catalyst coupled system has developed into an advanced means of improving ozone synthesis and attracted widespread attention. This review aims to provide a systematic summary for the research status of the DBD-catalyst coupled system in the field of ozone synthesis. Firstly, the structure of DBD reactors (type and shape of the electrode, etc.), catalyst types and the coupling method of DBD and catalysts (such as catalyst packing, catalyst coating/film) for the DBD-catalyst coupled system are discussed. Subsequently, the relevant mechanisms involving plasma gas-phase reactions and gas-solid interface reactions for elevating discharge ozone synthesis through coupling catalysts with DBD are summarized and analyzed. Afterwards, the research status of the DBD-catalyst coupled system in the field of ozone synthesis is surveyed. At present, the optimal ozone synthesis performance of the reactor with packed catalyst in air plasma (γ-Al2O3 sphere) is 0.96 g/Nm3 and 103 g/kWh, and in oxygen plasma (SiO2 particle) is 130 g/Nm3 and 91 g/kWh, respectively. For the reactor coupled with a catalyst coating, the performance reaches 19.3 g/Nm3 and 320 g/kWh in oxygen plasma (TiO2). Then, advanced plasma parameter detection techniques (i.e., optical emission spectroscopy and two-photon absorption laser-induced fluorescence) are expatiated to observe the changes in plasma parameters within the discharge system and then provide strong support for further in-depth research and analysis of the enhancement mechanism of coupling catalysts on ozone synthesis. Finally, a short conclusion, together with the current challenges and future opportunities of the DBD-catalyst coupled system in improving ozone synthesis, are proposed.