Modeling of bimetallic Pt-based electrocatalyst on extended-surface support for advanced hydrogen compression and separation

Electrochemical hydrogen compression (EHC) process can be used to purify and separate hydrogen from its mixtures. In this regards question of carbon monoxide (CO) tolerance of electrocatalyst, used in such a process (e.g., Pt), becomes extremely relevant. One of the approaches to increase CO toleran...

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Bibliographic Details
Published in:International journal of hydrogen energy 2014-05, Vol.39 (15), p.7805-7810
Main Authors: Tokarev, A., Bessarabov, D.G.
Format: Article
Language:English
Subjects:
Adsorption
Alternative fuels. Production and utilization
Applied sciences
Carbon monoxide
CO tolerance
Compressing
Density functional theory
Electrocatalysts
Energy
Exact sciences and technology
Extended-surface support
Fuels
Hydrogen
Molecular dynamics
Platinum
Stretching
Surface chemistry
Tolerances
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Summary:Electrochemical hydrogen compression (EHC) process can be used to purify and separate hydrogen from its mixtures. In this regards question of carbon monoxide (CO) tolerance of electrocatalyst, used in such a process (e.g., Pt), becomes extremely relevant. One of the approaches to increase CO tolerance is to add ruthenium metal to platinum electrocatalyst. Results of density functional theory modeling of CO adsorption on Pt–Ru alloy slabs and edges are presented in this paper. It was found that Pt2Ru alloy has higher CO adsorption energy difference on Ru and Pt atoms, ECO(Ru)–ECO(Pt), than that of PtRu2. Effect of contraction and stretching of support on CO adsorption was also investigated: stretching increases CO adsorption energy, while contraction has opposite effect. We also found that 110 surface and edges of electrocatalyst have higher CO adsorption energy than 111 surface. Finally, we considered an elementary nano-object of the modeled extended surface, whiskerette. Using molecular dynamics with Sutton-Chen potential, we simulated annealing of platinum whiskerette at 800 K and calculated trend of CO coverage: number of CO active sites increases with temperature, and after cooling, it does not reach the initial level. •CO adsorption on Pt–Ru alloys was modeled.•CO tolerance of Pt2Ru alloy is higher than that of PtRu2.•110 or stretched slab, edge have higher CO adsorption energy than 111 slab at equilibrium.•Annealing increases number of CO active sites.
ISSN:0360-3199
1879-3487
DOI:10.1016/j.ijhydene.2014.03.138