Adsorption of CO2 at T = 298 K and Pressures up to 6 MPa on Quasi Nonporous Al13Fe4

Al13Fe4 is a complex metallic alloy known as an active and selective semi hydrogenation catalyst. However, it is also a representative of aluminum compounds often used in the field of lightweight construction, mainly for the manufacturing of laminates. In this context, adsorption of solvents or atmospheric components on the metal surface can have a negative impact on the adhesion properties. We take CO2 as an example and report its adsorption on quasi nonporous Al13Fe4 particles at T = 298 K and pressures up to 6 MPa. Investigation of such low-adsorptive materials requires small measurement uncertainty, not achievable with commercial instruments. Hence, measurements were conducted using an optimized gravimetric sorption analyzer. Different surface-modified Al13Fe4 samples were studied with a combined expanded uncertainty (k = 2) in adsorption capacity ranging (from 0.001 to 0.025) mmol·gsam−1. Two differently treated samples showed a significant increase in maximum adsorption capacity compared to the untreated material. Further surface-functionalization of Al13Fe4 through hydrophobic coating using the trimethylsilylester of phenylphosphonic acid reduced the maximum adsorption capacity for each treated sample. Thermophysical and other physical properties of Al13Fe4 are presented. In particular, adsorption capacities are related to the specific surface areas of the samples that were determined with a volumetric apparatus.