The present disclosures and inventions relate to a catalyst composition for the selective conversion of a hydrogen/carbon monoxide mixture (syngas) to C2+ hydrocarbons. The composition includes a catalyst having the formula CoMnxSiyOz, wherein the molar ratio of x is from about 0.8 to about 1.2; wherein the molar ratio of y is from about 0.1 to about 1.0; and wherein the molar ratio of z is a number determined by the valence requirements of Co, Mn, and Si wherein the catalyst has a Scherrer crystallite size of less than about 40 nm, wherein the Si is silica.