Chromium doping and in-grown heterointerface construction for modifying Ni3FeN toward bifunctional electrocatalyst toward alkaline water splitting

Abstract

Exploring high-performance non-noble metal electrocatalysts is pivotal for eco-friendly hydrogen energy applications. Herein, featuring simultaneous Chromium doping and in-grown heterointerface engineering, the Cr doping Ni3FeN/Ni heterostructure supported on N-doped graphene tubes (denoted as Cr–Ni3FeN/Ni@N-GTs) was successfully constructed, which exhibits the superior bifunctional electrocatalytic performances (88 mV and 262 mV at 10 mA cm−2 for HER and OER, respectively). Furthermore, an alkaline electrolyzer, employing Ni3FeN/Ni@N-GTs as both the cathode and the anode, requires a low cell voltage of 1.57 V at 10 mA⋅cm−2. Cr doping not only modulates the electronic structure of host Ni and Fe but also synchronously induces nitrogen vacancies, leading to a higher number of active sites; the in-grown heterointerface Cr–Ni3FeN/Ni induces the charge redistribution by spontaneous electron transfer across the heterointerface, enhancing the intrinsic catalytic activity; the N-GTs skeleton with excellent electrical conductivity improves the electron transport and mass transfer. The synergy of the above merits endows the designed Cr–Ni3FeN/Ni@ N-GTs with outstanding electrocatalytic properties for alkaline overall water splitting.