Comparison of surface coverage values of tungsten-alumina catalysts determined by different methods

Abstract

Abs~a~Apparent surface coverage (ASC) of a series of ttmgsten-alumina catalysts was determined by the eloctrophoretic migration method (EM). A linear increase in W coverage with increasing W loading (up to 13.1 wt.% W) was observed. The results were in close agreement with those obtained previously by ion scattering spectroscopy (ISS) and low temperature CO adsorption.

Sol–gel La 2 O 3 –ZrO 2 mixed oxide catalysts for biodiesel production

“…The isoelectric point was calculated by the graphical representation of the zeta potential versus solution pH. The apparent surface coverage (ASC) of ZrO 2 by La 2 O 3 was calculated from equations previously validated by ion scattering spectroscopy (ISS) and XPS [43][44][45] as follows:…”

Insights in the mechanism of deposition and growth of RuO2 colloidal nanoparticles over alumina. Implications on the activity for ammonia synthesis

“…For ␥-Al 2 O 3 , the reference was obtained from the alumina used as support in the preparation of catalysts. Apparent surface coverage (ASC) of alumina, with RuO 2 or metallic Ru, was calculated from equations previously validated by XPS and ISS [20][21][22], as follows:…”

Slurry Impregnation of ZrO2 Extrudates: Controlled EggShell Distribution of MoO3, Hydrodesulfurization Activity, Promotion by Co

“…These values do not differ much from the value 2.1 (determined by the simplified mass titration method) of pure MoO 3 , and thus the surfaces of the prepared catalysts could be assumed to have been mostly covered by MoO 3 . This has alrady been assumed in the literature about monolayer MoO 3 /Al 2 O 3 [39], WO 3 / Al 2 O 3 [40], or V 2 O 5 /Al 2 O 3 [41] catalysts for example. The surfaces of the prepared MoO 3 monolayer catalysts were therefore negatively charged and the adsorption of dissolved Co cations from the slightly basic CoCO 3 /H 2 O slurry of pH 8.6 was favored.…”