(460h) Hydrogen Production From Ethanol Steam Reforming Over Supported Cobalt Catalysts

Authors: 
Lin, S. S., Northwestern University


Hydrogen production was carried out via ethanol steam reforming over supported cobalt catalysts. Wet incipient impregnation method was used to support cobalt on ZrO2, CeO2 and CeZrO4 followed by temperature-programmed reduction to attain supported cobalt catalysts. It was found that the non-noble metal based 10 wt.% Co/CeZrO4 is an efficient catalyst to achieve ethanol conversion of 100% and hydrogen yield of 82% (4.9 mol H2/ mol ethanol converted) at 450 oC , which is superior to 0.5 wt.% Rh/Al2O3. However, the activity of Co/CeZrO4 catalysts was significantly influenced by the reduction process. Based on the results, when supporting cobalt, CeZrO4 gives the synergic effect of CeO2 and ZrO2 to promote ethanol conversion while suppress methanation, which is leading to a high hydrogen yield at low temperature. Under the high space velocity (56,000 h-1), the hydrogen yield was found to gradually decrease 30% in 6 hours possibly due to the coke formation on the catalyst.

In this study, in situ X-ray diffraction (XRD) was used to investigate the crystallographic evolution of Co/CeZrO4 in various reduction processes. In addition, thermogravimetry-mass spectroscopy (TG-MS) was used to identify the coke-inducing species in the product steam, which might help to elucidate the deactivation mechanism over Co/CeZrO4 catalysts.