XAFS study on Mn-Ni/Al₂O₃ catalyst for carbon dioxide reforming of methane

Abstract

As an effective catalyst for carbon dioxide reforming of methane, manganese-promoted Ni/Al2O3 catalyst was studied with XAFS. The catalysts after the reduction above 1073 K contained the metallic nickel, and several phases of manganese were shown by XANES and EXAFS. Results of EXAFS curve fitting indicated that the surface of large metallic nickel particles was partly covered with patches of MnO and metallic Mn. Radial structure function (RSF) of Mn K-edge showed the peaks due to Mn-Ni scattering without Mn-Mn scattering, indicating that the metallic manganese was attached to nickel in a highly dispersed state. Separate manganese phase was also formed without interaction with nickel.

Tar Reforming in Model Gasifier Effluents: Transition Metal/Rare Earth Oxide Catalysts

“…Either or both ways, the picture is purely of “doped” REO and/or Al 2 O 3 . While the shape of the XANES spectrum (Figure ) is similar to Mn0.8/Al and MnAl 2 O 4 , the pre-edge and crest energies for Mn0.2/Ce/Zr/Al are shifted to higher energies for Mn0.2/Ce/Zr/Al (Figure ), suggesting a structure different than for Mn/AlO x . Therefore, the only things we can conclude from the XANES itself are that there are both Mn 2+ and Mn 3+ present, and there are both lower and higher coordination numbers associated with these oxidation states.…”

Adsorption of rare earth metals (Sr2+ and La3+) from aqueous solution by Mg-aminoclay–humic acid [MgAC–HA] complexes in batch mode

“…29 Furthermore, the O interaction in [MgAC-HA] complexes with Sr 2+ and La 3+ by extended X-ray absorption ne structure (EXAFS). 30 In detail, X-ray absorption ne structure (XAFS) was measured at 8C nano-probe XAFS beamline (BL8C) of Pohang Light Source (PLS-II) in the 3.0 GeV storage ring, with a ring current of 320 mA. The radiation source of BL8C is a tapered invacuum-undulator.…”