Performance of Ca1-xSrxTiO3 as barriers in dielectric barrier discharges with different Sr content

Plasma assisted catalytic technology, which uses synergetic technologies between the catalyst and plasma, has attracted much attention over the past several years. Theoretically, permittivity of a dielectric barrier influences the transferred charge of a microdischarge; thus high permittivity can improve the plasma reaction in a dielectric barrier discharge (DBD) plasma reactor. Despite the increased interest in the chemical processes, very little has been reported concerning the influence of materials of a dielectric barrier on DBD plasma reactions, since a high permittivity barrier generally exhibits low fracture strength and low dielectric strength making it break down under strong current pulses. In the present study, Ca1-xSrxTiO3 ( 0.1 <= x <= 0.4) which possesses a high permittivity and a high fracture strength was prepared by liquid phase sintering and was used as a dielectric barrier for the destruction of carbon dioxide by a DBD plasma reaction. The permittivity of Ca1-xSrxTiO3 ( 0.1 <= x <= 0.4) increased with increasing SrTiO3 content; however, the observed CO2 conversion became greatest using Ca0.8Sr0.2TiO3 and then decreased with increasing SrTiO3 content. These results imply that the reactivity of CO2 destruction does not monotonously increase with increased permittivity of the Ca1-xSrxTiO3 barriers. Both amplitude and density of the current pulses ignited by Ca0.8Sr0.2TiO3 were much greater than that of Ca0.6Sr0.4TiO3. Further, it was confirmed that a plasma reaction uniformly proceeded using the Ca0.8Sr0.2TiO3 barrier, but proceeded non-uniformly using the Ca0.6Sr0.4TiO3 barrier by observing the carbon deposition profiles on the surfaces of the barriers.