Steam Reforming of Ethanol on Copper Catalysts Derived from Hydrotalcite-like Materials

Steam reforming of ethanol (SRE) and sorption enhanced steam reforming of ethanol (SE-SRE) on Cu,Zn,Al materials was studied in the temperature range between 200 and 600 degrees C for hydrogen production. Precursors with different structures, such as a hydrotalcite-like compound (CuZnAl-HT), zincian malachite derivative (CuZnAl-REF, a reference catalyst precursor for the synthesis of methanol) and amorphous material with embedded copper particles (CuZnAl-ECP), were employed to obtain the active phases. Among the three samples used, the CuZnAl-HT catalyst shows the highest activity (ethanol and water conversion) and selectivity (hydrogen yield). This material also shows a satisfying stability, as the ethanol conversion only decreases around 20% at 400 degrees C during 12 h of lifetime test. In addition, carbon dioxide uptake during the transient period of SRE was found on the CuZnAl based materials. Especially for the CuZnAl-HT catalyst a SE-SRE phenomena was perfectly observed at 400 degrees C due to a relative good interaction of carbon dioxide formed in the initial transient period of reaction and the ZnO phase present in the catalyst. Probably, also retained traces of the hydrotalcite-like precursor structure on the CuZnAl-HT catalyst used are responsible for the observed SE-SRE phenomena. Breakthrough tests were performed with the CuZnAl-HT catalyst. This material shows a carbon dioxide adsorption capacity from 0.11 to 0.18 mol/kg, which is a prerequisite for SE-SRE.