Acetaldehyde behavior over platinum based catalyst in hydrogen stream generated by ethanol reforming

• Published in: International journal of hydrogen energy Vol. 35; no. 24; pp. 13200 - 13205
• Main Authors: de Lima, Adriana F.F., Colman, Rita C., Zotin, Fátima M.Z., Appel, Lucia G.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2010; Elsevier
• Subjects: Acetaldehyde; Alternative fuels. Production and utilization; Applied sciences; Bonding; Carbon monoxide; Catalysts; Decarbonylation; Energy; Ethyl alcohol; Exact sciences and technology; Fuel cells; Fuels; Hydrogen; Hydrogen storage; Platinum; Pt based catalyst; Scission; Pt based catalyst; Decarbonylation; Fuel cells; Acetaldehyde; Measurement; Methane; Greenhouse effect; Purification; Ethanol; Hydrogen; Reforming; Condensation; Electrocatalysis; Dehydrogenation; Platinum; Catalysis; Carbon monoxide; Proton exchange membrane fuel cells; Catalyst; Fuel cell; Hydrogen production; Low temperature
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2010.09.030

Due to the greenhouse effect, hydrogen production from bioethanol reforming is a very important subject in heterogeneous catalysis research. Pt based catalysts are employed in H 2 purification processes and also as electrocatalysts of PEM (“Proton Exchange Membrane”) fuel cells. Hydrogen obtained from ethanol reforming may contain, as contaminants, acetaldehyde and small amounts of CO. This aldehyde can be decarbonylated on Pt based catalysts generating carbon monoxide and methane, rendering the hydrogen purification more challenging. Moreover, acetaldehyde might also change the electrocatalyst behavior. Therefore, this contribution aims at studying the acetaldehyde behavior in the presence of platinum based catalysts in hydrogen atmosphere. The Pt/SiO 2, Pt/USY catalysts and an electrocatalyst were characterized by n-butylamine, H 2 and CO 2 adsorption, ATG/DTG measurements and cyclohexane dehydrogenation reaction. It was observed that the acid–basic properties of the supports promote condensation reactions. When in contact with Pt based catalysts, acetaldehyde undergoes C–C and C O bond scissions. The former occurs at a wide range of temperatures, whereas the latter only at low temperatures (<200 °C). The C–C bond scission (decarbonylation) produces methane and CO. The C O bond scission generates carbon residues on the catalyst as well as oxygen species, which in turn is able to eliminate CO from the catalytic surface. The data also show that decarbonylation is not a structure-sensitive reaction.