Ethanol Steam Reforming on Rh Catalysts: Theoretical and Experimental Understanding
Zhang, J.; Zhong, Z.; Cao, X.; Hu, P.; Sullivan, M.B.; Chen, L.
ACS Catalysis 4(2): 448-456
2014
ISSN/ISBN: 2155-5435 DOI: 10.1021/cs400725k
Accession: 083752808
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Summary
Through combined theoretical and experimental efforts, the reaction mechanism of ethanol steam reforming on Rh catalysts was studied. The results suggest that acetaldehyde (CH3CHO) is an important reaction intermediate in the reaction on nanosized Rh catalyst. Our theoretical work suggests that the H-bond effect significantly modifies the ethanol decomposition pathway. The possible reaction pathway on Rh (211) surface is suggested as CH3CH2Oh → CH3CH2O → CH3Cho → CH3Co → CH3 + Co → CH2 + Co → Ch + Co → C + CO, followed by the water gas shift reaction to yield H2 and CO2. In addition, we found that the water-gas shift reaction, not the ethanol decomposition, is the bottleneck for the overall ethanol steam reforming process. The Co + Oh association is considered the key step, with a sizable energy barrier of 1.31 e V. The present work first discusses the mechanisms and the water effect in ethanol steam reforming reactions on Rh catalyst from both theoretical and experimental standpoints, which may shed light on designing improved catalysts.