Pore Structure−Chemical Composition Interactions of New High Surface Area Manganese Based Mesoporous Materials. Materials Preparation, Characterization, and Catalytic Activity

Abstract

The present article deals with pore structure−chemical composition interactions of new high surface area manganese based porous mixed oxides (MANPOs). These mixed oxidic materials were prepared by the dropwise addition of a solution containing metal nitrate into an acetonic solution containing the trinuclear complex of manganese [Mn3O(CH3COO)6(pyr)3]ClO4, which is water sensitive. The CPSM model (corrugated pore structure model) was employed in pore structure investigations of the MANPO materials containing Al, Fe, La, La + Ce, and La + Sr. Successful CPSM simulations of nitrogen sorption hysteresis loops for the MANPO solids enabled the evaluation of intrinsic pore size distributions (PSDs) and tortuosity factors. The latter vary over the approximate range τCPSM = 3.0−5.7 (i.e. τCPSM≈ 3 for materials containing Al or Fe and τCPSM = 4.7−5.7 for those containing La, La + Ce, or La + Sr). These values are typical of porous catalysts and are higher than those reported for MCM-41 materials (ca. τCPSM = 1.00−2...