A significant support effect was observed for the aqueous-phase reforming (APR) of glycerol over a series of Pt- and PtRe-loaded ceria-, ceria–zirconia-, zirconia-, and titania-supported catalysts. Glycerol conversion rates decreased in the order Pt/TiO2>Pt/ZrO2>Pt/CeZrO2>Pt/CeO2. Upon addition of Re, APR activities of all the Pt catalysts increased. Re promotion for glycerol APR was strongest for PtRe/CeO2. Pt/CeO2 was least active because of the incomplete reduction of Pt. Pt was more easily reduced in PtRe/CeO2 because of the strong Pt–Re interaction. On comparison with previous data on Pt/C and PtRe/C, the oxide-supported catalysts were more active in the WGS reaction, with the titania-supported catalyst as the most active, which was a result of the activation of water on the titania support. The acidity of these groups also resulted in increased CO cleavage rates of Pt/TiO2 relative to the rates of Pt/C in APR. A more detailed comparison of Pt(Re)/C and Pt(Re)/TiO2 is made. Monitoring acetaldehyde decomposition to determine the rate of CC bond cleavage evidenced a strong promoting effect of Re on the supported Pt catalysts. All catalysts produced carbon monoxide, methane, and ethanol during acetaldehyde decomposition; notably, Pt(Re)/TiO2 also formed products such as ethylene, ethane, propylene, and propane, indicative of a mechanism also involving ethanol dehydration and olefin coupling to CHx surface intermediates derived from acetaldehyde. The activity in overall glycerol conversion in APR decreased in the order PtRe/C>PtRe/TiO2>Pt/TiO2>Pt/C.
If you can't find a tool you're looking for, please click the link at the top of the page to "Go to old article view". Alternatively, view our Knowledge Base articles for additional help. Your feedback is important to us, so please let us know if you have comments or ideas for improvement.