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

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.