Enhancing catalyst dispersion on carbon supports

The separate roles of the surface and solution chemistry in promoting the dispersion of carbon-supported catalysts has been investigated. Using an aqueous molybdenum precursor solution for illustration, it was shown that it is not only the quantity, but also the quality, of the oxygen functional groups that control, upon their chemical activation, the extent of catalyst dispersion. In order to produce highly dispersed Mo/C catalysts, two conditions must be simultaneously met: (a) the carbon surface must yield upon TPD a high CO/CO₂ evolution ratio, and (b) the pH of the impregnating solution must be low enough to activate the Mo precursor adsorption sites.