Characterization and catalytic properties of nanosized cobaltate particles prepared by in situ synthesis inside mesoporous molecular sieves
Bulk lanthanum cobaltate (LaCoO3) with perovskite-like structure and LaCoOx supported onto the mesoporous MCM-41 molecular sieve were synthesized by the conventional citrate method. The prepared samples were characterized by XRD, nitrogen BET measurements, H2-temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), XAFS and SEM-energy-dispersive X-ray (EDX) techniques. The turnover frequency of the supported cobaltate in methanol oxidation is two orders of magnitude larger than that of the bulk perovskite material. Based on the characterization results, it is concluded that the supported cobaltate does not form species of LaCoO3 short-range order in MCM-41. The high activity is related to a highly disordered, oxygen-deficient Co oxide phase, which is probably stabilized by the La ions present.
Journal: Applied Catalysis A: General - Volume 312, 8 September 2006, Pages 59–66