A pyridinic Fe-N4 macrocycle models the active sites in Fe/N-doped carbon electrocatalysts

Abstract Iron- and nitrogen-doped carbon (Fe-N-C) materials are leading candidates to replace platinum catalysts for the oxygen reduction reaction (ORR) in fuel cells; however, their active site structures remain poorly understood. A leading postulate is that the iron-containing active sites exist primarily in a pyridinic Fe-N 4 ligation environment, yet, molecular model catalysts generally feature pyrrolic coordination. Herein, we report a molecular pyridinic hexaazacyclophane macrocycle, (phen 2 N 2 )Fe, and compare its spectroscopic, electrochemical, and catalytic properties for ORR to a typical Fe-N-C material and prototypical pyrrolic iron macrocycles. N 1s XPS and XAS signatures for (phen 2 N 2 )Fe are…

• UD
  U.S. Department of Defense

  Award: DE-AC02-06CH11357
• UD
  U.S. Department of Energy

  Awards: AC02-06CH11357, DE-AC02, 06CH11357, DE-AC02-06CH11357, DE-AC02-
• OO
  Office of Science

  Awards: DE-AC02-06CH11357, DE-AC02, 06CH11357, AC02-06CH11357
• ND
  National Defense Science and Engineering Graduate
• BE
  Basic Energy Sciences

  Awards: DE-AC02, AC02-06CH11357, 06CH11357