Novel Ce-modified cobalt catalysts supported over α-Al2O3 open cell foams for lean methane oxidation

A series of CeO2-modified Co3O4 catalysts supported over α-Al2O3 foams was prepared by solution combustion synthesis and examined for the lean methane oxidation. Two different fuels were used namely, urea and glycine, with varying fuel/oxidiser (Φ) ratio. The catalysts were characterised by SEM-EDX, STEM-HAADF coupled to EDX mapping, ICP-AES, WDXRF, N2 physisorption, XRD, HRTEM, Raman spectroscopy, XPS, H2-TPR and CH4-TPRe, and their activity in the abatement of methane was analysed under realistic conditions. The use of glycine produced catalysts with significantly better morphological and structural properties. Likewise, a favoured insertion of cerium cations into the Co3O4 spinel lattice was observed, which caused a significant distortion of the spinel structure, thereby leading to a higher amount of mobile oxygen species capable of oxidising methane. These beneficial structural alterations were more pronounced with higher Φ ratios.