Research Interests
Non-Thermal Plasma technology holds significant potential for activating CH4 and CO2 molecules, enabling their conversion into H2 and other valuable chemicals under mild conditions. However, conventional thermal catalysts which are primarily heat responsive often lack compatibility with non-thermal plasma environment, where reaction mechanisms and dominant species differ considerably. Moreover, as CO2 has a higher bond dissociation energy than CH4, there is a necessity to design a catalyst that can enhance CO2 dissociation kinetics to improve overall DRM efficiency. This study integrates ferroelectric materials into plasma catalytic systems enhancing energy transfer to reactant molecules, increasing electron density in discharge regions, and elevating average electron energy – key factors critical to increasing the conversion rates of both CH4 and CO2 in plasma-assisted DRM. Perovskite oxides synthesized via the Pechini method were categorized into three classes: titanates (BaTiO3, CaTiO3, SrTiO3), zirconates (BaZrO3, CaZrO3, SrZrO3), and niobates (KNbO3, NaNbO3, KNaNbO3), each exhibiting distinct curie temperatures and ferroelectric properties. Niobate-based ferroelectric catalysts, particularly KNbO3 and NaNbO3, demonstrated the highest CH4 conversions of 71.7% and 71.9%, CO2 conversions of 62.4% and 60.5%, H₂ yield of 33.6% and 33.3%, and CO yield of 33.5% and 32.9%, respectively. KNbO3 resides in its orthorhombic ferroelectric phase at 800 V and 5 kHz enabling sustained polarization and enhanced surface charge effects. To further enhance performance and stability of traditional supports, ferroelectric KNbO3 was incorporated into Al2O3 and SiO2 using a co-precipitation method. This integration further improved CH4 and CO2 conversions to 75.5% and 54.6% with Al2O3, and 81.7% and 64.6% with SiO2. To study the effect of loading active metal, nickel (5 wt%) was introduced via incipient wetness impregnation. However, its addition to ferroelectric catalysts such as KNbO3-Al2O3 and KNbO3- SiO2 led to reduced CH4 and CO2 conversions and a shift in product selectivity towards CO, highlighting the pivotal role of spontaneous polarization in directing plasma induced reaction pathways. In contrast, paraelectric perovskites exhibited poor catalytic performance due to their inability to maintain polarization under plasma conditions either due to inherently non-ferroelectric structures or low curie temperatures. Overall, among all tested catalysts, ferroelectric KNbO3 based catalysts demonstrated superior control over electric field interactions at the catalyst surface, promoting localized micro-discharges, enhancing CO₂ dissociation, and reducing energy losses.