Protecting active species from aggregation and corrosion may be feasible to obtain stable catalytic activities for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, bamboo-shaped N-doped carbon nanotubes (hollow BS-NCNTs as shells) are self-generated to in situ wrap the Co/CoOx schottky junctions (cores) to obtain the Co/CoOx@BS-NCNTs as bifunctional ORR/OER catalysts by using the Co-chelated melamine precursor. For ORR, Co/CoOx@BS-NCNTs (700 degrees C) exhibits more positive peak (0.822 V vs. RHE) and half-wave (0.842 V vs. RHE) potential than those of commercial Pt/C (10 wt%). Superior ORR activity is mainly attributed to the enriched coordination-unsaturated Co2+ (tetrahedral Co-Td(2+)) in the CoOx wrapped in the tubular structure of BS-NCNTs featuring high electrical conductivityand active N species. Moreover, the pi-pi bonds of CNTs are activated by N substitution, which provides a stunning electron capture and transmission capability for enhancing ORR activity. For OER, Co/CoOx@BS-NCNTs (700 degrees C) obtains a smaller potential (1.590 V vs. RHE) than that of RuO2/C at 10 mA cm(-2). The outstanding OER activity and durability of Co/CoOx@BS-NCNTs (700 degrees C) originates from strong interactions between C-skeleton and Co species, and efficient Co3+/Co4+ (Co4+OOH as active sites) transition protected by the externally-grown CNTs. Furthermore, abundant oxygen vacancies on CoOx surface can facilitate the adsorption of OH-/or OER-related intermediates to improve OER activity. Therefore, this study provides a promising strategy to develop NCNTs-wrapped Co species with high catalytic activity and stability for energy conversion. (C) 2019 Elsevier Inc. All rights reserved.