A process for increasing the hydrogenation activity, particularly the carbon monoxide hydrogenation activity, of a catalyst or catalyst precursor comprised of a particulate solids support component and a catalytic metal, or metals component, preferably cobalt; cobalt alone or cobalt and an additional metal, or metals added to promote or modify the reaction produced by the cobalt. Treatment of the catalyst, or catalyst precursor is conducted at low temperature ranging from ambient to about 275° C. sufficient to form on the surface of a catalyst precursor, e.g., a cobalt catalyst precursor, a cobalt metal hydroxide, low valence cobalt metal oxide, or mixture of cobalt metal hydroxide and low valence cobalt metal oxide. Sometimes also metallic metal, e.g., cobalt, is also formed, and dispersed on the surface of the support. On reduction, as may be produced by contact and treatment of the catalyst or catalyst precursor with hydrogen, the oxidized metal, or metals component of the catalyst or catalyst precursor is reduced to elemental or metallic metal, and the activity of the catalyst thereby increased. A catalyst, activated or produced in this manner, is a useful composition of matter, the catalyst being particularly useful for efficiently conducting carbon monoxide hydrogenation reactions, especially F-T synthesis reactions, to provide a variety of useful products.