Catalysis Letters, Vol.150, No.9, 2688-2694, 2020
Enhancement of Low-Temperature NH3-SCR Catalytic Activity and H2O Resistance Ability Over MnOx/TiO2 Catalyst by Expanded Graphite
A combination of large void volume and rich microporous structure enables expanded graphite (EG) to possess excellent adsorption properties. Furthermore, it is discovered to be hydrophilic with the capability of adsorbing NOx. The ball milling method was applied in preparation of the MnOx/TiO2 modified by expanded graphite catalysts with the aim to improve SCR activity and resistance to H2O and SO2. An optimal SCR performance was obtained over the catalysts with 5 wt% EG doping. Subsequently, an investigation was conducted by XPS, NH3-TPD, H-2-TPR into the understanding of the SCR catalytic performance of MnOx/TiO2 at low-temperature. As revealed by the investigation results, the catalyst modified by EG had more Mn4+ species and could absorb more oxygen, which allowed it to present more surface acid sites that could boost SCR activity. In addition, it was discovered that the introduction of EG could facilitate the improvement on the resistance to H2O and SO2. Graphic Expanded graphite (EG) has used to improve the SCR activity and resistance to H2O and SO2 over the MnOx/TiO2. The catalyst with the addition of 5% EG was found to have more surface acid sites, surface adsorbed oxygen and Mn4+ species. [GRAPHICS] .