Ni-substituted LaMnO3 perovskites for ethanol oxidation

The B-site substitution of LaMnO3 perovskites by Ni was investigated under the oxidation of ethanol. Proper characterization techniques, including BET surface area measurement, XRD, FTIR, XPS, TPR, O-2-TPD, and FE-SEM experiments were performed to survey the physicochemical properties of perovskites. The results reveal that up to 25% of Mn can be replaced by Ni; beyond this limit, segregated NiOx can be synthesized. Inserting Ni into the solid solution of perovskite yields unique bridging lattice oxygen sites (Ni-O-Mn) in Ni-doped LaMnO3. Based on catalytic performance in ethanol oxidation, the Ni-O-Mn sites are likely to promote ethanol conversion and the oxidation of acetaldehyde to CO2 at low reaction temperatures. The abatement of intermediates over Ni-O-Mn sites is hypothesized and a plausible reaction pathway is proposed. Moreover, the time on-stream testing revealed that the interaction between Ni and Mn is likely to enhance perovskite's thermal stability in ethanol oxidation.