Nanostructured ceria supported Pt and Au catalysts for the reactions of ethanol and formic acid

Authors: Aysegul Ciftci, D.A.J. Michel Ligthart, Pietro Pastorino, Emiel J.M. Hensen

Abstract:
Decomposition reactions of ethanol and formic acid were studied over a series of Au and Pt nanoparticle catalysts. CeO₂ nanorods and nanocubes served as model supports representing the {1 1 0} and {1 0 0} surfaces of CeO₂ nanocrystals. Pt was more active than Au in low temperature (below 400^◦C) steam reforming, oxidation and decomposition (without an oxygen source) of ethanol. Similar trends were observed in the WGS reaction. Different from Au, for Pt the initial step of ethanol dehydrogenation to acetaldehyde is followed by the cleavage of the C–C bonds of acetaldehyde to CH₄ and CO due to thehigher Pt–C bond strength when compared to that of Au–C. The catalysts supported on nanorod-shaped ceria were more active than those derived from nanocube-shaped ones in ethanol steam reforming and WGS reactions due to the abundance of OH species formed by activation of water on the oxygen vacancies in the CeO₂{1 1 0} surfaces of ceria nanorod supported catalysts. Complete oxidation of ethanol to CO₂ and H₂O was observed over the Pt and Au supported CeO₂ (rod) catalysts. For the former, complete oxidation took place starting from temperatures as low as 150^◦C. These catalysts were active for decomposition offormic acid starting from near-ambient temperatures (T > 50 ◦C) up to 200^◦C, at which temperature formic acid was completely converted over all the catalysts. Au was more active and it selectively dehydrogenated formic acid into CO₂ and H₂. The intrinsic activity of the CN-leached Au/CeO₂(rod) catalyst containing highly dispersed sub-nanometer Au clusters was higher than the parent catalyst. Pt, on the other hand, showed lower selectivity toward the dehydrogenation pathway due to its higher activity in WGS reaction and enhanced Pt–O bond strength resulting in decarbonylation of formic acid. 

Keywords:
Gold
Platinum
Ceria
Ethanol conversion
Formic acid decomposition

Published in: Applied Catalysis B: Environmental (Volumes 130–131, Pages 1-336, 7 February 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Nanostructured ceria supported Pt and Au catalysts for the reactions of ethanol and formic acid

Bình luận của bạn

*

*

*

*

 Captcha

Gửi bình luận nhập lại