XPS studies of NO selective reduction catalysts after SO₂ poisoning

Abstract

The effect of an SO,-water vapour-air mixture on the structure of Fe3+-, Cuz+-, Coz+-or Ni*+-active carbon catalysts used for selective catalytic reduction of NO with ammonia was studied by low-temperature argon sorption and XPS. Active material reacted with oxidation products of SO, to form appropriate sulphates. The reaction rate, expressed as surface sulphur-to-cation ratio, depended on the distribution of active material on the starting samples. The distribution of Fe3+, Cu2+, NiZ+ and Coz+ changed during the reaction as a result of movement of the cations into the porous system and was accompanied by some decrease in specific surface area and partial blocking of micropores.

Effect of Activated Carbon Surface Oxygen- and/or Nitrogen-Containing Groups on Adsorption of Copper(II) Ions from Aqueous Solution

“…The binding energy (BE), the relative peak area (rpa), and the full width at half-maximum (fwhm) for separate peaks were estimated and collected. According to the literature data, [22][23][24][25][26][27][28][29][30][31] the XPS Cu 2p 3/2 lines calibrated with standard samples were found at binding energies (BE) of 932.4, 933.4, and 934.8 eV for copper in oxidation states 0, +,1, and +2, respectively. Beyond the difference in energy shift, another important feature of the copper(II) XP spectrum is the presence, or absence, of a satellite peak at 942.5 eV.…”

Effect of manganese substitution on the structure and activity of iron titanate catalyst for the selective catalytic reduction of NO with NH3

“…8A. Two characteristic peaks ascribed to Fe 2p 3/2 at 711.4 eV and Fe 2p 1/2 at 724.9 eV appeared for each Fe-containing sample, indicating that the iron species in these samples was in Fe 3+ oxidation state [46]. It was reported in our previous study that the iron species in iron titanate catalyst possessed higher binding energies than that in pristine Fe 2 O 3 due to the strong interaction between iron and titanium species [6], and the substitution of partial Fe by Mn did not change this situation.…”

Catalytic conversion of syngas to mixed alcohols over CuFe-based catalysts derived from layered double hydroxides

“…44 After calcination, the obtained S 2 -CuFeMg-MMO sample shows two distinguishable main peaks at B711.2 (Fe 2p 3/2 ) and B724.3 eV (Fe 2p 1/2 ), indicating the presence of the Fe 3+ cation. 45 After reduction, the Fe 2p 3/2 peak shifts towards lower binding energy, coupled with the appearance of a peak at 710.6 eV, which can be identified as Fe 3 O 4 . 43 An inconspicuous peak observed at 706.94 eV implies the presence of Fe 0 on the surface.…”