Low Surface Area Cerium Oxide Thin Film Deposition on Ceramic Honeycomb Monoliths

Abstract

In this work, the development of acid-free stable oxide dispersions has been studied to obtain thin oxide layers onto substrates of complex geometry to obtain structured catalysts and reactors for process intensification. In particular, attention has been paid to syngas production in steam reforming process using CeO2-based oxides. For this purposes commercial cerium oxide (3 m2 g-1) was selected as model of low surface area catalyst precursor and dip-coating as deposition technique. Ceramic monoliths were used as structured supports (diameter 1 cm, length 1.5 cm). A slurry formulation, including the powder, glycerol, polyvinyl alcohol and distilled water allowed to obtain the proper rheological behavior and stability of the suspension. The addition of a relatively small PVA quantity changes dispersion properties, allowing to properly tune viscosity. Results were evaluated in terms of coating load and adhesion performance. Final coating loads of about 18 %wt. were obtained performing multiple depositions. A good homogeneity of the washcoat layers was found, accompanied by a quite good adhesion (6% wt of coating loss after ultrasound treatment).