Catalyst characterisation testing and analysis.
Intertek provides a wide range of Catalyst Characterisation laboratory testing expertise and services.
Catalyst Characterisation Analysis:
Catalyst Surface Composition:
XPS provides composition to a depth of 3nm, along with chemical species identification. SIMS identifies molecular species lifted off the outermost layer of the surface but is not quantitative. STEM analysis complements this when used to analyse the edge of particles of individual phases within a catalyst.
Catalyst Metal Crystallite Compositions:
These are often most effectively measured on a crystallite-by-crystallite basis by high resolution analytical STEM. In some cases different compositions will result in changes in the metal lattice parameters that can be measured by XRD.
Catalyst Pore Systems and Blockage:
Porosity can be characterised by adsorption isotherms, usually with nitrogen. Apart from closed pores and macropores (>50 nm), total pore volume and pore size distribution can be measured. Catalyst size distribution ensures efficient transport of reactants and products to and from the active surface. In some catalyst systems, smaller sizes are also used to limit unwanted reactions. Reaction byproducts and feedstock impurities result in loss of loss of activity through pore blockage. Pore volume and size distribution analysis detects these processes by comparing used catalysts with fresh.
Catalyst Surface Segregation:
Data from catalyst bulk composition analysis, TEM/STEM analysis of sub volumes, XPS and SIMS provide data over a wide range of length scales from which surface segregation effects in complex multiphase systems can be deduced.
Catalyst fouling will typically result in porosity reduction and narrowing of pores. These can be investigated by nitrogen adsorption methods (BET surface area, pore size and pore size distribution).
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