Non-thermal plasma CO₂ conversion enhanced by CeO₂-doped BaTiO₃ and internal electrode cooling

This work investigates the combined impact of using cerium oxide (CeO₂) as a catalyst and internal electrode cooling on CO₂ conversion into CO in a non-thermal plasma reactor packed with barium titanate (BaTiO₃). BaTiO₃ is successfully modified with CeO₂ via a wetness impregnation method, yielding samples with 0%, 3%, 17%, and 57% CeO₂ loadings. It is observed that a low CeO₂ loading of 3% increased the CO₂ conversion and energy efficiency by up to 38% compared to the undoped BaTiO₃, while higher loadings (17% and 57%) led to reduced performance. The use of a cooling strategy through the inner electrode, using air convection (passive cooling) or water flow (active cooling), increases both CO₂ conversion and energy efficiency by strengthening plasma generation and reducing the recombination of CO and O₂. Specifically, conversion increases from 18% without cooling to 36% with passive cooling, and further to 47% when combined with 3% CeO₂ doping and active water cooling. In parallel, the energy efficiency increases from 0.3 - 2% (undoped, uncooled) to 0.5 - 16% with 3% CeO₂ doping under both passive and active internal cooling.