Effect of Cerium Promoters on an MCM-41-Supported Nickel Catalyst in Dry Reforming of Methane
Ahmed S. Al‐Fatesh, Rawesh Kumar, Samsudeen Olajide Kasim, Ahmed A. Ibrahim, Anis H. Fakeeha, Ahmed E. Abasaeed, Hanan Atia, Udo Armbruster, Carsten Kreyenschulte, Henrik Lund, Stephan Bartling, Yahya Mohammed, Yousef Abdulrahman Albaqmaa, Mahmud S. Lanre, Mayankkumar L. Chaudhary, Fahad S. Al‐Mubaddel, Biswajit Chowdhury
Abstract
0.1–3 wt % Ce-promoted MCM-41-supported nickel catalysts were prepared for dry reforming of CH4 (DRM) and characterized by surface area and pore analyses, powder X-ray diffraction , temperature-programed reduction with H2, temperature-programed CO2 desorption, X-ray photoelectron spectroscopy, thermogravimetric analysis, and scanning transmission electron microscopy using a high-angle annular dark field. Notably, 5Ni0.5Ce/MCM-41 has a bimodal distribution of NiO crystallites inside and outside the pores of MCM-41, the highest number of basic sites inducing profound CO2 interactions with the surface, and metallic nickel particles interacting with the support for facilitating CH4 dissociation. In addition, a thin surface layer of ceria provides surface oxygen species for carbon deposit oxidation. All these physiochemical properties ensured >90% conversion (H2/CO ∼ 1) over 330 min on stream and >80% conversion over 75 h of time on stream (H2/CO = 0.98) over the 5Ni0.5Ce/MCM-41 catalyst. A higher ceria loading than 0.5 wt % masked the active Ni sites with a ceria layer, which diminished the number of basic sites and deteriorated the catalytic performance.