Iron doped nickel ditelluride hierarchical nanoflakes arrays directly grown on nickel foam as robust electrodes for oxygen evolution reaction

The highly applied cost effective electrocatalyst for the oxygen evolution reaction is pivotal to various energy storage and conversion devices. In this work, Fe-doped NiTe₂ nanoflakes have been synthesized via facile one-step solvothermal approach. The hierarchical Ni_0.4Fe_0.6Te₂ nanoflakes grwon on Nickel foam (NF) demonstrate the high electrochemical activity and stability towards Oxygen evolution reaction in 1 M KOH solution. The optimized Ni_0.4Fe_0.6Te₂/NF needs only 190 mV overpotential to produce 10mAcm⁻² and can afford the higher current densities for the OER of 400mAcm⁻² and 500mAcm⁻² at overpotential of 300 mV and 330 mV, respectively. The small R_ct value for the Ni_0.4Fe_0.6Te₂/NF suggests the reduced polarization resistance and electrode-electrolyte resistance. Moreover, it showed the extraordinary stability of 30 hours in controlled electrolysis experiment with no significant change in oxygen evolution reaction (OER) activity. The synergistic effect of bimetal atoms are considered mainly responsible for the high catalytic activity and stability, providing assistance in inducing the lattice distortion into the crystal structure of NiTe₂ that activates the evolution of surface partial oxygen atoms, enabling lattice oxygen mechanism. Even after prolong activity of OER; formation of dynamic NiFeOOH(Te)/NF species sustains excellent OER activity. This work provides facile synthetic approach to develop highly applied low cost and binder free electrocatalyst.