Intrinsic properties of active sites for hydrogen production from alcohols without coke formation

Abstract

The detailed reaction pathway and coke formation mechanism over Pt/metal oxide nanoparticles during the steam reforming of ethanol (SRE) at 300 °C were studied. The catalysts were prepared by incipient wetness impregnation method and were characterized with CO pulse chemisorption, BET surface measurement, oxygen adsorption, ethanol-TPD, NH3-TPD, and TPO. The SRE activity of the catalysts with steam/ethanol molar ratio of 3/1 was tested using a continuous fixed-bed reactor. Strong interaction between Pt and supports causes lower H2 production temperatures and no C2H4 formation, while weak interaction leads to C2H4 formation and strong bonded CO on Pt particles during ethanol-TPD. H2 production over Pt-based catalysts is mainly resulted from the decomposition and dehydrogenation of ethanol, and decarbonylation of acetaldehyde. Meanwhile, coke can be formed from acetaldehyde, acetone, C2H4 and CO. However, when the interaction between Pt and supports is weak, more coke is formed especially from acetone, C2H4 and CO. When the interaction is strong, no coke formation is observed due to high oxygen storage capacity of the catalyst.