Influence of Mg Addition on the Catalytic Activity of Alumina Supported Ag for C3H6-SCR of NO

Abstract

The influence of different magnesium (Mg) weight percentages (1, 2.5, 5, 7.5 and 10) over silver (3 wt%) impregnated alumina (SA) catalyst was investigated for the reduction of NO by C 3 H 6 . Mg doped SA catalysts were prepared by conventional impregnation method and characterized by XRD, BET-SA, ICP-MS, XPS, SEM, UV-DRS, H 2 -TPR and O 2 -TPD. The existence of MgO and MgAl 2 O 4 phases on Mg doped SA catalysts were observed from XRD and XPS analyses. Existence of high percentage MgAl 2 O 4 phase on 5% Mg doped SA catalyst (Mg (5) SA) enhances the dispersion and stabilization of silver phases (Ag 2 O). Mg (5) SA catalyst shows a 51% of high selectivity (NO to N 2 ) in presence of SO 2 (80 ppm) at low temperatures (350°C) and maintained high selectivity's with a wide temperature window (350-500°C). An optimal high surface availability of Ag 0 and Ag ? species were observed from XPS analysis over Mg (5) SA catalyst. H 2 -TPR analysis shows high temperature reduction peak over Mg (5) SA compared to SA catalyst. XPS analysis confirms the high percent availability of MgAl 2 O 4 species over Mg (5) SA catalyst. DRIFTS study reveals the molecular evidences for the evolution of enolic species during NO reduction over the highly active Mg (5) SA catalyst at low temperatures. It also confirms further transformation of enolic species into -NCO species with NO ? O 2 and finally into N 2 and CO 2 .

Development of Active and Stable Low Nickel Content Catalysts for Dry Reforming of Methane

“…Besides, Mg.Al.700 and Mg.Al.800 show reflections (2θ = 31.3°; 37°; 45°; 55.5°; 59°; 65°) assigned to the formation of the MgAl2O4 phase (ICDD file No. 00-021-1152) at higher calcination temperatures [27]. At 1000 °C, no reflection of the solid solution can be observed while peaks assigned to periclase MgO and MgAl2O4 phases are sharp and characteristic, indicating the high crystallinity of those phases.…”

“…Besides, Mg.Al. 700 [27]. At 1000 • C, no reflection of the solid solution can be observed while peaks assigned to periclase MgO and MgAl 2 O 4 phases are sharp and characteristic, indicating the high crystallinity of those phases.…”

Development of Highly Stable Low Ni Content Catalyst for Dry Reforming of CH4‐Rich Feedstocks

“…01‐071‐1176) and MgAl 2 O 4 (ICDD file No. 00‐021‐1152) crystalline phases (Figure a). The corresponding catalysts Ni/Mg 1.3 AlO x .1000 and La.Ni(CA)/Mg 1.3 AlO x .1000 display patterns close to that of the support, suggesting the formation of finely dispersed La 3+ and Ni 2+ species that are not detectable by XRD .…”

Effects of synthesis method on cation distribution and optical properties of Co/Cr co-doped MgGa2O4 nanoparticles

“…For Mg 1s spectra, peaks at ~1306 eV and ~1305 eV are assigned to Mg 2+ ions in octahedral and tetrahedral sites, respectively [15,16]. The fraction of octahedrally coordinated Mg 2+ ions is 0.62 for the sample synthesized by SG, and decreases to 0.32 for the sample synthesized by SSR.…”