Standard Article

O2 reduction and structure-related parameters for supported catalysts

Electrocatalysis

The oxygen reduction/evolution reaction

  1. S. Mukerjee1,
  2. S. Srinivasan2

Published Online: 15 DEC 2010

DOI: 10.1002/9780470974001.f205039

Handbook of Fuel Cells

Handbook of Fuel Cells

How to Cite

Mukerjee, S. and Srinivasan, S. 2010. O2 reduction and structure-related parameters for supported catalysts. Handbook of Fuel Cells. .

Author Information

  1. 1

    Northeastern University, Boston, MA, USA

  2. 2

    Princeton University, Princeton, NJ, USA

Publication History

  1. Published Online: 15 DEC 2010

Abstract

Supported electrocatalysts starting with the initial patent by Petrow and Allen opened up a new horizon in the field of fuel cell electrocatalysis. Choice of new chemical dispersion methods and choice of carbon support materials led to a quantum jump in the performance of low and intermediate temperature acid and alkaline fuel cells. Among the advantages realized early were: (i) lowering overpotential losses in the activation, mass transport and ohmic polarization regions; (ii) mitigating corrosion and sintering problems; and (iii) increased catalyst utilization and hence decreased cost of noble metals by one or two orders of magnitude. This chapter reviews the fundamental and technological progress in the research on supported electrocatalysts for both phosphoric acid fuel cells (PAFCs) and polymer electrolyte fuel cells (PEMFCs). Early developments in the realization of particle size effects and the interplay between electronic and short range atomic order has been chronicled for the more kinetically difficult oxygen reduction reaction, until the advent of Pt alloy electrocatalysts. The effect of carbon support is also examined from the perspective of possible catalyst-support synergy both in terms of imparting improved electrocatalysis but also in terms of increased stability (resistance to sintering). Methods of dispersing metals on carbon support are chronicled along with some new developments. In addition, newer techniques involving synchrotron X-ray techniques are presented in terms of elucidating the true nature of electrocatalysis of oxygen reduction reaction. Some new perspectives on the continued use of these supported electrocatalysts are presented, especially in the emerging field of new synthesis routes for making tailored Pt alloy electrocatalysts.

Keywords:

  • agglomeration/sintering;
  • corrosion;
  • Ostwald ripening (dissolution/precipitation);
  • particle size effect;
  • amorphous/preferred orientation;
  • electronic factors;
  • short range order;
  • alloy electrocatalysts;
  • surface composition changes;
  • effect of geometric and electronic factors;
  • performance degradation in PAFCs and PEMFCs;
  • high surface area carbons;
  • corrosion;
  • pretreatment (heat/chemical);
  • adhesion of electrocatalysts;
  • amorphous/preferred orientation;
  • carbides/oxides;
  • electronic conductivity;
  • stability