Facile synthesis of hierarchical CoMoO4@Ni(OH)2 core-shell nanotubes for bifunctional supercapacitors and oxygen electrocatalysts

Abstract

Abstract For the first time, hierarchical CoMoO4@Ni(OH)2 core-shell hollow nanotubes were synthesized using hydrothermal and ion-exchange route process. As supercapacitor material, the CoMoO4@Ni(OH)2 core-shell hollow nanotubes exhibited a high specific capacitance of 1246\u202fF\u202fg−1\u202fat a current density of 1\u202fA\u202fg−1, and 86.7% of the original capacitance was also retained at 5\u202fA\u202fg−1, indicating an excellent rate performance. Theoretical analysis showed that the surface capacitance dominated the total capacitance of the CoMoO4@Ni(OH)2 electrode. The asymmetric supercapacitor device based on CoMoO4@Ni(OH)2 and porous carbon exhibited high energy density of 62.5\u202fWh kg−1. In addition, the overpotential of the as-prepared material was 0.35\u202fV in the oxygen evolution reaction at the scan rate of 10\u202fmV\u202fs−1, showing high activity. All these electrochemical properties indicated that the fabricated hierarchical CoMoO4@Ni(OH)2 core-shell nanotubes were promising candidates for highly performed bifunctional supercapacitors and oxygen electrocatalysts.