A novel non-noble electrocatalyst with an average particle size of approximately 4 nm was prepared by heat-treating carbon-supported molybdenum tetraphenylporphyrin in a flow NH3 atmosphere. The effects of heating time and temperature on its electrocatalystic properties were investigated. The samples obtained were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and EDX. The results show that the synthesized catalyst has the same composition as that of MoN. This carbon-supported catalyst displays a strong activity towards oxygen reduction reaction (ORR) and a methanol-tolerant property. The catalyzed ORR proceeds by an approximate four-electron reduction pathway from O-2 directly to H2O. (C) 2007 Elsevier B.V All rights reserved.