Synergistic Tuning of Nickel Cobalt Selenide@Nickel Telluride Core–Shell Heteroarchitectures for Boosting Overall Urea Electrooxidation and Electrochemical Supercapattery

Abstract

Herein, we demonstrate the synthesis of bifunctional nickel cobalt selenide@nickel telluride (NixCo12-xSe@NiTe) core–shell heterostructures via an electrodeposition approach for overall urea electrolysis and supercapacitors. The 3D vertically orientated NiTe dendritic frameworks induce the homogeneous nucleation of 2D NixCo12-xSe nanosheet arrays along similar crystal directions and bring a strong interfacial binding between the integrated active components. In particular, the optimized Ni6Co6Se@NiTe with an interface coupling effect works in concert to tune the intrinsic activity. It only needs a low overpotential of 1.33 V to yield a current density of 10 mA cm−2 for alkaline urea electrolysis. Meanwhile, the full urea catalysis driven only by Ni6Co6Se@NiTe achieves 10 mA cm−2 at a potential of 1.38 V and can approach a constant level of the current response for 40 h. Besides, the integrated Ni6Co6Se@NiTe electrode delivers an enhanced specific capacity (223 mA h g−1 at 1 A g−1) with a high cycling stability. Consequently, a hybrid asymmetric supercapacitor (HASC) device based on Ni6Co6Se@NiTe exhibits a favorable rate capability and reaches a high energy density of 67.7 Wh kg−1 and a power density of 724.8 W kg−1 with an exceptional capacity retention of 92.4% after sequential 12 000 cycles at 5 A g−1.