Synergistic Tuning of Nickel Cobalt Selenide@Nickel Telluride Core–Shell Heteroarchitectures for Boosting Overall Urea Electrooxidation and Electrochemical Supercapattery
Diab Khalafallah, Weibo Huang, Mingjia Zhi, Zhanglian Hong
Abstract
Herein, we demonstrate the synthesis of bifunctional nickel cobalt selenide@nickel telluride (Ni x Co 12‐x Se@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 Ni x Co 12‐x Se nanosheet arrays along similar crystal directions and bring a strong interfacial binding between the integrated active components. In particular, the optimized Ni 6 Co 6 Se@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 Ni 6 Co 6 Se@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 Ni 6 Co 6 Se@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 Ni 6 Co 6 Se@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 .