Sorption-desorption properties of dual oxide gels in the system BeO-In_O3

[摘要] Water vapor sorption-desorption isotherms at 2° and 12° have been obtained for a series of eleven heat-treated (2 hour periods) gels selected at every 10 mole per cent in the system Be0-1n203. Two zones of enhanced adsorption occur at compositions of about 40-60 and 90 mole per cent BeO, in a plot of specific adsorptive capacity at constant P/P0 as a function of composition. Plots of BET surface area as a function of composition lead to the same conclusion. The two zones of enhanced adsorptive capacity correspond to the zones of mutual protection against crystallization previously detected by x-ray diffraction methods. Isosteric differential heats of adsorption are likewise higher in the regions of mutual protection. The observed enhanced composition zones of amount of adsorption and the enhanced heats of adsorption confirm a prediction set forth in an earlier paper. The most frequent uncorrected. Kelvin pore radii computed from the desorption isotherms are 125 A for pure In203 and 25 A for pure BeO. As the amount of BeO is increased the pore radii decrease regularly, the greatest changes occurring at compositions of 10 and 90 mole per cent BeO.

[发布机构] Rice University