NOVELTY - Catalyst precursor comprises: a microporous support; a non-noble metal precursor; and a pore-filler. Micropores of the microporous support are filled with the pore-filler and non-noble metal precursor so that the micropore surface area of the catalyst precursor is substantially smaller than the micropore surface area of the support when the pore-filler and non-noble metal precursor are absent.    USE - The catalyst precursor is useful to produce a catalyst, which is useful: as an oxygen reduction catalyst (preferred), a catalyst for the disproportionation of hydrogen peroxide or a catalyst for the reduction of carbon dioxide (all claimed); in cathode of fuel cells including acid or alkaline polymer electrolyte membrane fuel cells or direct alcohol fuel cells; and in metal-air batteries e.g. zinc-air batteries.    ADVANTAGE - The catalyst precursor provides: inexpensive non-precious metal catalysts for oxygen reduction reactions, thus offers an alternative to platinum-based catalysts; and commercial viability of polymer electrolyte membrane fuel cells. The catalyst obtained using the pyrolysis procedure has 10-100 times higher activity in a fuel cell than the catalyst obtained by simple adsorption or impregnation on carbon.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a catalyst comprising the catalyst precursor, where the catalyst precursor has been pyrolyzed so that the micropore surface area of the catalyst is substantially larger than the micropore surface area of catalyst precursor, provided that the pyrolysis is performed in the presence of a gas that is a nitrogen precursor when the microporous support, non-noble metal precursor and pore-filler are not nitrogen precursors;    (2) producing a catalyst precursor, comprising: providing a microporous support, a non-noble metal precursor and a pore-filler; and filling the micropores of the microporous support with the pore-filler and the non-noble metal precursor; and    (3) producing a catalyst, comprising: providing the catalyst precursor; and pyrolyzing the catalyst precursor.