Study On Performance Of Dielectric Barrier Discharge Plasma In CO₂ Decomposition

As a greenhouse gas,carbon dioxide（CO₂）has attracted worldwide attention.How to use CO₂ as a carbon resource to decompose and synthesize high value-added chemical products and fuels,such as carbon monoxide（CO）,methanol,ethanol and formaldehyde,has become a hot topic of research in many countries.At present,the main methods for converting CO₂ to CO mainly include thermal catalysis,electro-catalysis and plasma catalysis.Among them,the high-energy electrons in the plasma can break the carbon oxygen double bond of CO₂ and generate CO and O₂ in the process of contact with CO₂.However,this method always has the defects of low conversion and low energy efficiency.This paper mainly studies the application of dielectric barrier discharge（DBD）plasma in CO₂ decomposition process,especially the influence of packing material,packing mode and discharge parameters on CO₂ conversion and energy efficiency.The details are as follows:（1）Study on the performance of modified TiO₂ packing materials on CO₂ decomposition by DBD plasma.TiO₂ millimeter ball was successfully prepared as the packing material,the influence of doped substances such as CeO₂ and ZrO₂ on CO₂ decomposition by plasma was investigated,and the influence of discharge power and inlet flow rate on CO₂ conversion and energy efficiency was studied.The study found that TiO₂ millimeter ball can effectively improve the discharge degree of plasma,generate electron-hole pairs,promote the improvement of CO₂ conversion and energy efficiency,and doping ZrO₂ or CeO₂ can effectively improve the ability of plasma to decompose CO₂.Among them,when 5 wt% CeO₂/TiO₂ millimeter ball was used as the packing material,the effective discharge degree of the plasma reactor was the highest,and the CO₂ conversion reached 28.93%.（2）Study on the performance of packing method on CO₂ decomposition by DBD plasma.ZrO₂-CeO₂ millimeter ball was used as the packing material,different packing methods were designed,and the CO₂ conversion and energy efficiency under different conditions were investigated.It was found that the packing material with small particle size can increase the density of the contact points in the reactor,which is conducive to enhancing the discharge intensity in the reactor and increasing the probability of high-energy species to participate in the chemical reaction before quenching.The maximum CO₂ conversion and maximum energy efficiency reached 64.38% and 8.76% respectively.（3）Study on the performance of foamed metal materials on CO₂ decomposition by DBD plasma.The discharge mode of plasma,CO₂ conversion and energy efficiency under different conditions were investigated by using foamed metal materials with porous structure and conductive characteristics as the packing material.It is found that the foamed metal materials can change the discharge mode from filamentary discharge to the combination mode of filamentary discharge and surface discharge.The conductive property of the foamed metal can improve the conductivity of the entire discharge gap,increase the discharge current and energy utilization rate,and enhance the performance of CO₂ decomposition.When foamed Ti was used,the conversion and energy efficiency of CO₂ were as high as 46.61% and 8.85%.