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

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 C₂H ₄ formation, while weak interaction leads to C₂H ₄ 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, C ₂H₄ and CO. However, when the interaction between Pt and supports is weak, more coke is formed especially from acetone, C ₂H₄ and CO. When the interaction is strong, no coke formation is observed due to high oxygen storage capacity of the catalyst.