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Title: Effect of Organic Cations on Hydrogen Oxidation Reaction of Carbon Supported Platinum

Effect of organic cations on hydrogen oxidation reaction (HOR) of carbon supported platinum (Pt/C) is investigated using three 0.1 M alkaline electrolytes, tetramethylammonium hydroxide (TMAOH), tetrabutylammonium hydroxide (TBAOH) and tetrabutylphosphonium hydroxide (TBPOH). Rotating disk electrode experiments indicate that the HOR of Pt/C is adversely impacted by time-dependent and potential-driven chemisorption of organic cations. In-situ infrared reflection adsorption spectroscopy experiments indicated that the specific chemisorption of organic cations drives the hydroxide co-adsorption on Pt surface. The co-adsorption of TMA + and hydroxide at 0.1 V vs. reversible hydrogen electrode is the strongest; consequently, complete removal of the co-adsorbed layer from Pt surface is difficult even after exposure the Pt surface to 1.2 V. Conversely, the chemisorption of TBP+ is the weakest, yet notable decrease of HOR current density is still observed. The adsorption energies, ΔE, for TMA +, TBA +, and TBP + on Pt (111) surface from density functional theory are computed to be -2.79, -2.42 and -2.00 eV, respectively. The relatively low adsorption energy of TBP + is explained by the steric hindrance and electronic effect. This study emphasizes the importance of cationic group on HOR activity of alkaline anion exchange membrane fuel cells.
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [1] ; ORCiD logo [1] ;  [3] ;  [3] ;  [4] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. National Inst. of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)
  3. Rensselaer Polytechnic Inst., Troy, NY (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States)
Publication Date:
Report Number(s):
LA-UR-16-26356
Journal ID: ISSN 0013-4651
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 163; Journal Issue: 14; Journal ID: ISSN 0013-4651
Publisher:
The Electrochemical Society
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Energy Sciences
OSTI Identifier:
1345940