Electrophoretic deposition of Co–Me/ZnO (Me = Mn,Fe) ethanol steam reforming catalysts on stainless steel plates

A procedure for coating metal plates with powder catalysts was developed based on electrophoretic deposition (EPD), and tested to deposit three different Co-based catalysts for the steam reforming of ethanol on stainless steel plates. The catalysts contained 10 wt% Co and 1 wt% of Mn or Fe supported on ZnO, and were prepared by co-precipitation (Co–Mn/ZnO–P and Co–Fe/ZnO–P) and impregnation (Co–Mn/ZnO–I). EPD was performed suspending the powder catalysts in isopropanol, using a voltage of 100 V and a distance between electrodes of 2 cm. Polyethyleneimine (PEI, 1 g/L) was used as binder. Deposition time was fixed at 5 min, which gave a thickness of the catalyst layer from around 30–45 μm, depending on the catalyst. The activity of the catalyst plates was tested at 773 K using steam to carbon ratios of 3 and 4, under incomplete conversion conditions. All catalysts favored ethanol dehydrogenation to acetaldehyde, and steam reforming. Ethanol dehydration to ethylene and acetaldehyde cracking to methane and carbon monoxide were not favored, and the selectivity towards those products was very low.