skip to main content

DOE PAGESDOE PAGES

Title: Insights on the extraordinary tolerance to alcohols of Fe-N-C cathode catalysts in highly performing direct alcohol fuel cells

Direct alcohol fuel cells (DAFCs) represent the best alternative to batteries for portable and auxiliary power units application due to the high energy density of short chain alcohols. Currently, the utilization of the best platinum group metal (PGM) cathode catalysts is limited, not only by a high cost and scarce resources, but also by the inefficient oxygen reduction reaction (ORR) when permeated alcohols adsorb on the catalytic active sites. In this work, a highly active Fe-N-C catalyst derived from the pyrolysis of nicarbazin (a nitrogen charge transfer organic salt) and an iron precursor has been investigated to get insights on the extraordinary tolerance to the presence of alcohols (methanol and ethanol) of such a PGM-free catalyst. Density functional theory (DFT) calculations demonstrate for the first time that Fe-N 4 and Fe-N 2C 2 active sites preferentially adsorb oxygen with much higher energy than methanol, ethanol and products of partial ethanol oxidation (0.73–1.16 eV stronger adsorption), while nitrogen-carbon related sites (pyridinic and graphitic nitrogen) are much less selective towards ORR. Half-cell electrochemical characterization showed that the Fe-N-C catalyst overcomes Pt ORR activity in acidic medium with methanol or ethanol concentrations as low as 0.01 M. The feasibility of DAFCs operation basedmore » on high methanol (up to 17 M) and ethanol (up to 5 M) concentration thanks to the utilization of Fe-N-C cathode catalyst is demonstrated. Lastly, a new strategy is proposed for DAFCs where using Pt only at the anode and Fe-N-C at the cathode allows extending the device energy density compared to PGM-based catalysts at both electrodes.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [2] ;  [1] ;  [1]
  1. Istituto di Tecnologie Avanzate per l'Energia "Nicola Giordano" (ITAE), Messina (Italy)
  2. Univ. of New Mexico, Albuquerque, NM (United States)
  3. Univ. of New Mexico, Albuquerque, NM (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-16-29215
Journal ID: ISSN 2211-2855
Grant/Contract Number:
AC52-06NA25396; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Nano Energy
Additional Journal Information:
Journal Volume: 34; Journal Issue: C; Journal ID: ISSN 2211-2855
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
CMEM, University of New Mexico; USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 30 DIRECT ENERGY CONVERSION; Material Science
OSTI Identifier:
1345169
Alternate Identifier(s):
OSTI ID: 1396401