Cobalt[tetrakis(o-aminophenyl)porphyrin] (CoTAPP) was covalently anchored (CA) onto the surface of three carbon nanomaterials (CNMs; graphene, single-walled carbon nanotubes (SWCNT), and multi-walled carbon nanotubes (MWCNT)) via diazonium salt reactions, which is a simple and effective method to improve the electrocatalytic activity of CoTAPP for combination with CNMs. The electrocatalytic reduction of O 2 on glassy carbon electrodes (GCEs) modified with these CoTAPP-anchored CNMs established a pathway of four-electron transfer reductions to H 2 O. Among the CoTAPP-anchored CNMs, anchored graphene with CoTAPP showed the best electro-catalytic effect and the most efficient electrocatalytic performance for oxygen reduction reaction (ORR) without any precious metals.