Demonstration of the Use of 3D X-ray Tomography to Compare the Uniformity of Catalyst Coatings in Open-Cell Foams

Coating open-cell foams by a catalytic layer is a necessary step to obtain structured catalytic foam reactors. The dip-coating method, consisting of immersing the foam in a suspension or in a sol-gel, is generally used to obtain the coating. The excess of liquid has to be evacuated from the foam to obtain a thin layer. Different methods to remove this excess of liquid have been investigated in the present work. The objective was to show that 3D X-ray tomography coupled to image analysis could be a tool to discriminate the methods by analysing the spatial localisation of the catalyst layer throughout the whole foam samples. A simple blowing by air in every direction seems to not be appropriate to obtain uniform coatings.