Dielectric barrier discharge coupled with oxygen-vacancy-rich NiO-CeO2 for efficient and low-energy degradation of SF6

How to achieve low energy consumption and high degradation efficiency (DRE) under mild conditions is an important issue in the field of sulfur hexafluoride (SF 6 ) treatment. In this work, a new route of SF 6 degradation promoted by Ni-doped ceria (NiO-CeO 2 ) in a packed bed dielectric barrier discharge (PB-DBD) was proposed. The effects of Ni/Ce molar ratio, input power, SF 6 concentration and flow rate on the DRE of SF 6 were investigated. Compared with DBD or CeO 2 -DBD alone, the combination of DBD and NiO-CeO 2 can significantly promote the SF 6 degradation at lower input power. The Experimental results show that when the dosage of catalyst 1.5NiO-CeO 2 (Ni/Ce mole ratio is 1.5%) is 5 g, DBD input power is 50 W and SF 6 (1.5% SF 6 /98.5% Ar) flow rate is 100 ml·min −1 , the highest DRE can reach 97.7% and the energy yield can reach 11.5 gSF 6 ·(kWh) −1 . Adjusting the catalyst dosage according to the flux of SF 6 ( e.g., using 10 g catalyst to degrade SF 6 with a concentration of 1.5% and a flow rate of 80 ml·min -1 ), the DRE of nearly 99% can be achieved for a long time, which is crucial for industrial application. The mechanism deduction shows that the rich surface and mesopores of the catalyst are beneficial to the adsorption of SF 6 and intermediates, while the doping of Ni can significantly increase the content of oxygen vacancies to improve the degradation. Meanwhile, when NiO-CeO 2 is activated by DBD, the free O· can further promote the degradation. It is this coupling effect that leads to the high efficiency and low energy consumption of SF 6 degradation under mild conditions. It can be expected that this coupling technology route will have a good application prospect in the field of SF 6 treatment.