A pure Co metal target was sputtered onto carbon paper and heat treated in an NH3 environment to fabricate Co-based electrocatalysts for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFC). A 100 nm-thick Co-based electrocatalyst sample showed the highest current density among the samples examined. It was determined that the optimal level of Co needed to yield content for maximum current density is directly related to the formation of ligands between Co and carbon paper when linked by nitrogen. Unfortunately, lower levels of Co in carbon paper are not able to form sufficient ligands while excessive amounts of Co will in fact hinder the formation of ligands. Although the catalytic activity observed is not comparable to that of Pt/C catalysts yet, sputtered Co-based electrocatalysts show potential as non-precious metal electrocatalysts in fuel cell. (C) 2012 Elsevier B.V. All rights reserved.