Developing　a　non-noble　metal　nanostructure　based　highly　active　nanocatalyst　for　sensitive　detection　of　small　molecules　is　of　great　interest　due　to　its　large　active　surface　area　and　rapid　catalytic　activity　towards　analytes.　In　this　work,　we　demonstrate　the　synthesis　of　porous　cobalt　oxide　nanocolumn　arrays　(Co3O4　NCs)　and　explore　them　as　an　efficient　catalyst　material　for　electrochemical　determination　of　hydrogen　peroxide　(H2O2)　in　real　samples　(river　water　and　antiseptic　solutions).　The　morphology　and　crystalline　properties　of　the　as-synthesized　Co3O4　NC　structures　are　characterized　by　using　scanning　electron　microscopy　(SEM),　transmission　electron　microscopy　(TEM),　X-ray　diffraction　(XRD),　and　electrochemical　methods.　Unlike　Co3O4　nanoparticles　(Co3O4　NPs),　the　Co3O4　NCs　show　significantly　higher　sensing　performance　towards　the　electrochemical　reduction　of　H2O2　in　0.1　M　NaOH　solution.　The　presence　of　nanoporous　structures　in　Co3O4　NCs　could　provide　a　large　specific　surface　area,　higher　conductivity　and　rapid　analyte　diffusion,　which　makes　them　a　promising　candidate　for　detection　of　H2O2.　The　amperometric　analysis　shows　that　Co3O4　NCs　exhibited　a　faster　electrocatalytic　response　towards　a　wide　concentration　range　of　H2O2　(100　to　2000　μM)　with　the　lowest　limit　of　detection　(LOD)　of　0.28　μM　(S/N　=　3).　The　Co3O4　NC　electrode　is　highly　selective　for　detecting　H2O2　in　the　presence　of　major　important　biomolecules　such　as　glucose,　ascorbic　acid,　uric　acid,　dopamine,　and　other　anionic　interfering　compounds.　These　results　demonstrate　that　Co3O4　NCs　serve　as　a　potential　sensing　platform　towards　the　electrochemical　detection　of　small　molecules.　©　2019　The　Royal　Society　of　Chemistry.