The latter exhibit greater redox ability of the manganese species and a higher density of active surface oxygen species with respect to the perovskite precursor. In the light of the experimental results, such performances can be related to the formation of a meso/macro-porous structure conferring high surface area and good accessibility of the active surface sites. Superior catalytic properties of ε-MnO 2 were observed toward HCHO oxidation as well as a good catalytic stability with respect to other macro-mesoporous counterparts. In our case, this soft process allowed us to obtain the ε-MnO 2 phase with hierarchical porosity without any template. Specifically, extending the acid etching duration promotes the surface area and pore volume of the materials while developing interconnected macro-mesoporous networks. Strength and oxidizing properties of the acid used as modifying agent strongly impact textural and redox surface properties of the resulting materials. About Guillaume Richard - GEDCOM Source R-2138817487 Public Member Trees Online publication - Provo, UT, USA: The Generations Network, Inc., 2006.Original data - Family trees submitted by Ancestry members. This transformation proceeds through a soft-chemical process involving the dissolution of trivalent lanthanum and manganese from the perovskite structure and the dismutation of Mn 3+ cations into MnO 2 and Mn 2+ species. Guillaume Rochard, 49 ans, est diplômé de la Toulouse Business School et auditeur de la 59 e session nationale de l’Institut des hautes études de défense nationale (IHEDN). The LaMnO 3 transformation was fully investigated using ICP, XRD, N 2 physisorption, TPR, TPD, SEM, TEM/EDS and XPS. Promotion of the HCHO oxidation over gold supported on Co-promoted ceria catalysts can be related to the higher concentration of oxygen vacancies and an improvement in the redox properties, which can contribute to the better activation of O 2 and an enhancement of the oxygen mobility.A simple template-free method, based on a mineral acid etching process using manganite perovskite (LaMnO 3) as precursor, was successfully developed to obtain a series of 3D meso/macro-porous materials. Furthermore, no marked changes were found in gold dispersion upon adding cobalt. Guillaume Rochard is Executive Vice President Strategy, Partnerships and Institutional Affairs at Naval Group. X-ray photoelectron spectroscopy (XPS) characterization of the fresh catalysts indicated that the Au species were mainly in a slightly ionic δ + valence state, but did not exclude the possibility of metallic gold. Hierarchical porous -MnO2 from perovskite precursor. Based on the HCHO amount (in μmol) converted into CO 2 per gram of gold per second after 40 h on stream, the 1.5Au/CeCo catalyst demonstrated the best activity (∼3.9) as compared to the other catalysts (≤2.0). Yin Xu, Jrmy Dhainaut, Guillaume Rochard, Jean-Philippe Dacquin, Anne-Sophie Mamede, et al. The 3 wt% Au catalysts demonstrated a higher HCHO conversion than their low-gold counterparts (1.5 wt% Au), a remarkable improvement in the HCHO conversion was observed using Co-promoted ceria (9 mol%). All of the supported Au catalysts exhibited HCHO oxidation into CO 2 at 25 ☌ and demonstrated a great stability for the time on stream (40 h). The fresh supported Au catalysts were characterized using several techniques in order to investigate their morphological, structural and redox properties before being tested for formaldehyde (HCHO) total oxidation. Au catalysts with loadings of 1.5 and 3 wt% were dispersed over CeO 2 and Co (9 12 mol%) promoted CeO 2, using the deposition–precipitation method, followed by calcination at 350 ☌.
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