Studies on pore systems in catalysts II. The shapes of pores in aluminum oxide systems

摘要: Abstract Complete adsorption-desorption curves of nitrogen have been measured on aluminum oxide systems, including boehmites various origin and bayerite, as well aluminas obtained by dehydrating these starting materials heating at temperatures. The hysteresis loops can be described according to a classification given in an earlier study; they belong types A, B, or E, combinations them, that classification. conclusions with respect the shapes pores which drawn from are discussed. gelatinous boehmite it consist spaces between small fibrillar particles form sheets. At higher temperatures widen pore walls smoothen. Microcrystalline prepared hydrothermal conversion sheetlike 150 °C, is built up very irregularly shaped its formed particles. Hydrothermal treatment yields far more regularly platelets, forming approximately rectangular cross sections. Well-crystallized shows different system; narrow addition wide original ones, but disappear again Bayerite preparations behave less gibbsite, publication.