Study On CO₂ Decomposition Via Dielectric Barrier Discharge Plasma Synergistic Catalysis

Utilization of carbon dioxide it has great significance for solving environment pollution and energy crisis. Due to the stable thermodynamic properties of carbon dioxide, carbon dioxide utilization conversion has always been a hot spot and key point in the environmental protection.The low-temperature plasma generated by high-energy electrons collidsion with gas molecules can occur or atomic reaction section collision response range of gas molecules or atoms, which can promote are difficult or impossible chemical methods. The non-thermal plasma providing a new technical plan for decomposition and transformation carbon dioxide. At present, the study of decomposition and transformation of carbon dioxide has been paid increasing attention in the field of the non-thermal plasma.Recently relevant work is focused on the study of the decomposition CO₂ by the non-thermal plasma. The main results are as follows:1. Firstly, we designed a self-cooled dielectric barrier discharge reactor compared with the traditional cylindrical dielectric discharge reactor. we found that using circulating water to do grounding can make more uniform discharge in a timely manner, withdrawal the heat generated by the reaction. The influence factors includes the discharge frequency, the circulating water temperature and electrical conductivity.2. The catalytic decomposition of CO₂ in the plasma of zirconia and glass beads was investigated. The result showed that:（a） The packing dielectric mainly affects CO₂ in the dielectric barrier discharge plasma electron impact dissociation reaction through the influence of the energy distribution of electrons in the plasma. The conversion of CO₂ increased from 26.1% to 32.9% and 52.1% in glass beads and zrconia pellets packed reactor compared with no paking materials.（b） Filling medium with the larger the pore volume can get a smaller decomposition rate of CO₂. The result showed that a large amount of CO₂ is adsorbed in the pore channels of the filled medium, and the discharge occured on the external surface of the medium.（c） The acid-base properties of packing dielectric affected decomposition reaction through the chemisorption of CO₂ on surface basic sites.（d） CO oxidation reaction is the main adverse reaction of CO₂ decomposition reaction. It is also one of the main factors affecting CO₂ decomposition. The experimental results showed that plasma filling medium played a great role in the decomposition of CO₂.3. The catalytic decomposition of CO₂ in the plasma packing with TiO₂、γ-Al2O3 and MgO was investigated. In the TiO₂-packed and MgO-packed reactor, the conversion of CO₂ increased from 26.1% to 32.6% and 31.4%, respectively. The synergistic effect is mainly manifested in the introduction of the catalyst, which improves the decomposition rate of CO₂, and the interaction between the plasma and catalyst causes the change of the reaction process. Such as the change of electron and electron hole generation, plasma induced adsorption and desorption, reaction gas adsorbed on the catalyst surface caused by the residence time, discharge status change caused by the dielectric constant of the catalyst.