Novel alumina-supported cobalt nitride catalysts with Co loading ranging from 1 to 10 wt% prepared by NH(3)-temperature-programmed reaction were investigated as potential catalysts for preferential CO oxidation (PROX) in excess H(2) at high temperatures. The formation of the CO(4)N phase was confirmed by a combination of XRD and XPS, and the Co 2p binding energies of CO(4)N reported previously were corrected to 798.2 +/- 0.2 and 782.5 +/- 0.2 eV. We observed that the catalytic activities of these nitrided Co/gamma-Al(2)O(3) catalysts were greatly related to their Co loadings. The nitrided 3 wt% Co/gamma-Al(2)O(3) catalyst showed the best PROX performance in temperature range of 200-220 degrees C, which was quite different from Co oxide precursor but was similar to Pt-group metals. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.