Transition metal phosphide catalysts for hydrogen oxidation reaction

A series of transition metal phosphides consisting of tungsten (WP), cobalt (Col?), nickel (NiP), nickel-tungsten (Ni-WP), cobalt-tungsten (Co-WP) and cobalt-molybdenum (Co-MoP) was prepared by a temperature-programmed reduction process. Hydrogen oxidation activities for the phosphide compounds were studied. The hydrogen oxidation reaction (HOR) was determined using a half-cell rotating disc electrode in a 0.5 M H2SO4 electrolyte. In addition, the passivity of the phosphides in an acidic environment was studied by ICP. The Co-WP demonstrated the highest activity for the HOR based on chronoamperometry and the exchange current density. The single WP exhibited a low HOR activity, but the incorporation of Ni or Co enhanced the activity. In contrast, WP exhibited a high passivity, while NiP and Col? dissolved in the 0.5 M H2SO4. The high activities over Co-WP and Ni-WP were attributed to the role of WP in preventing the Co and Ni from corroding in the acidic media. (C) 2009 Elsevier BIN. All rights reserved.