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Cobalt-based materials exhibit high theoretical specific capacitance and desirable electrocatalytic activity. However, their practical specific capacitance and electrocatalytic activity are significantly constrained by a lack of active sites and limited conductivity. Herein, N, P and S-doped hollow Co3O4@Co3V2O8heterostructure nanocube is reasonably constructed via in-situion exchange method combined with calcination strategy. Besides, the relationship of heterogeneous interface and heteroatom doping on electrochemical performance is explored. The heterogeneous interface provides rich active sites and accelerates electron transfer. Additionally, N, P, and S-doping regulate the internal electronic structures, boost ion transfer rates, and increase active sites. The hollow structure accelerates the adsorption and desorption processes due to the increased electrochemical reaction sites. Benefiting from internal electronic structure and structural advantages, N, P, S-Co3O4@Co3V2O8exhibits low overpotentials (561 mV and 649 mV at the current density of 50 mA/cm2and 100 mA/cm2), low Tafel slopes (100.9 mV/dec), prospective specific capacitance (550.2 F/g) and outstanding charge/discharge behavior with remarkable life span. N, P, S-Co3O4@Co3V2O8based device delivers favorable energy density (21.3 Wh/kg at 802.3 W/kg), which surpasses most of the latest cobalt-based materials. Overall, this work provides novel insights into the development of highly active and durable bifunctional electrode materials.

Co3O4has been paid much attention in the field of supercapacitors and oxygen evolution reaction attributed to its high theoretically specific capacitance, earth abundant, cost-effective, and environment friendly. However, the commercial application of Co3O4was greatly limited by the poor electrical conductivity and inferior active sites. Herein, the N-CoMoO4@Co3O4double-shell nanoboxs were successfully prepared through in situ ion-conversion-exchange treatment coupled with the following calcination process. The hollow/porous transition metal oxide-based nanomaterials delivered large surface areas and rich active sites, and boosted electron transfer. Hybridizing with other components increased electrochemical reactive active sites, optimized the superiority of different components. The nitrogen doping resulted in high density of surface reaction sites. As a result, the obtained N-CoMoO4@Co3O4double-shell nanoboxs performed superior specific capacitance (520 F/g), favorable charge/discharge rate and remarkable cycling stability. Moreover, the advanced asymmetrical supercapacitors prepared by N-CoMoO4@Co3O4double-shell nanoboxs supplied remarkable energy density. Furthermore, when employed as oxygen evolution reaction electrocatalysts, N-CoMoO4@Co3O4double-shell nanoboxs yielded favorable desirable overpotential (380 mA/cm2) and low Tafel slope of 87.8 mV/dec. Overall, this work provided theoretical guidance for the design of efficient dual-function electrocatalysts.