Catalyst Support – Materials & Composition

The nature of catalyst support phases can be established by XRD and changes monitored. Support characteristics of interest may include composition, heterogeneity, crystal structure, crystallite size and crystallite shape. Surface area, pore volume and pore size distribution are fundamental characteristics of the catalyst architecture. They can be measured by nitrogen adsorption methods. These parameters are often particularly useful for comparison of batches and deterioration through loading of active ingredients or through blockages in use.  Crystallite shape can be measured where this is likely to arise, e.g. zinc oxide or titanium oxide.

Catalyst support composition is often assumed but it is good practice to verify batches. Even when the elemental composition is known, the phase composition may not be obvious, e.g. ‘alumina’ can be one of several transition alumina types or the high temperature corundum phase, all having significantly different properties. Titanium oxide can be in the form of rutile, anatase or the much less common brookite.