In the last few decades, renewable resources received considerable attention for the production of hydrogen. Herein, we present oxygen evolution from water using cobalt oxide based nanomaterials (Co₃O₄, Co₃O₄@SiO₂, Co₃O₄/TiO₂, Co₃O₄/Fe₂O₃ and ZnO@SiO₂). These nanomaterials were grown in a controlled size and were characterized by various spectroscopic techniques. The Co₃O₄, Co₃O₄@SiO₂, Co₃O₄/TiO₂, Co₃O₄/Fe₂O₃, and ZnO@SiO₂ were screened for their electro-catalytic properties towards H₂O oxidation. All cobalt oxide based nanomaterials showed good oxygen evolution activity and high stability in alkaline conditions. However, Co₃O₄@SiO₂ showed a higher current density at lower overpotentials and a lower Tafel slope (107.7 mV dec⁻¹) as compared to Co₃O₄/TiO₂, Co₃O₄/Fe₂O₃, ZnO@SiO₂, and Co₃O₄. At 1.0 V (overpotential 735 V versus Ag/AgCl), Co₃O₄@SiO₂ supplied a current density of 63.0 mA cm⁻² in 0.3 M KOH solution. This indicated a superior electrocatalytic performance then the other electrocatalyst. The excellent electrocatalytic performance of Co₃O₄@SiO₂ might be due to certain structural features, which elevate its electrical conductivity, its oxidizing aptitude, and the affinity between OH⁻ ions and the Co₃O₄@SiO₂ surface and ultimately enhance smooth mass transports, which give superior oxygen evolution activity to Co₃O₄@SiO₂.