Bimetallic Ni–Mo alkoxide was synthesized and exploited as the single-source precursor for the solution-processed deposition of the mixed-oxide layers on different conducting surfaces. Upon potential cycling in 1 M NaOH, these composites convert, in situ, into highly porous NiO_x/NiOOH catalysts characterized by the high electrocatalytic activity for water oxidation under both basic (pH 13.6) and near neutral (pH 9.2) conditions.