Effect of the non-thermal plasma treatment on the structure and SCR activity of vanadium-based catalysts

Abstract

A catalyst V-Ce-Ni/TiO2 was synthesized using the ultrasound-assisted impregnation, and the catalysts V-Ce-Ni/TiO2-NP and V-Ce-Ni/TiO2-HP were prepared by N2 and H2 non-thermal plasma-treatment, respectively. The structure and catalytic activity of the catalysts was characterized and evaluated in the study. BET results indicated that the specific surface area over V-Ce-Ni/TiO2-NP catalyst (50 m2·g−1) was higher than that of untreated catalyst (49 m2·g−1). And the characterization results of XRD, TEM, SEM and EDS showed that the plasma treated catalysts have smaller particle size, higher dispersion and better uniform distribution of active sites on the catalyst surface than the untreated catalyst. Besides, the results of XPS and NH3-TPD revealed that non-thermal plasma treatment generated more oxygen vacancy on the catalyst surface than the untreated catalyst, and then increased the amount of acid sites. H2-TPR results suggested that the interaction between active components and support (TiO2) of V-Ce-Ni/TiO2-HP was stronger than that of V-Ce-Ni/TiO2-NP. The results of NH3-SCR (selective catalytic reducing of NO with ammonia) showed that above 90% of NO conversion was obtained over V-Ce-Ni/TiO2-HP catalyst in the temperature ranging from 195 °C to 414 °C, and 100% of NO conversion was maintained in the temperature regions of 230 °C to 350 °C. The catalytic activity of the catalysts of non-thermal plasma treatment was enhanced at low temperature (below 260 °C), and the operating temperature window (T90) of the catalysts was widened.