Doping and heterojunction strategies for constructing V-doped Ni3FeN/Ni anchored on N-doped graphene tubes as an efficient overall water splitting electrocatalyst

Exploring the integration regulation strategies to boost the electrocatalytic performance and elucidating the manipulation mechanism are critical for the hydrogen economy. Herein, heteroatom doping and heterojunction strategies were integrated to engineer a V-Ni3FeN/Ni@N-GTs bifunctional electrocatalyst, where the V-Ni3FeN/Ni heterojunction consisting of V doped Ni3FeN and Ni was anchored on N-doped graphene nanotubes (N-GTs). Benefiting from the modulation of the d-band center of hosts Ni and Fe by V doping and the regulation of local charge distribution induced by the V-Ni3FeN/Ni heterojunction, combined with the introduction of the conductive N-GTs skeleton, V-Ni3FeN/Ni@N-GTs delivers overpotentials of 66 and 252 mV at 10 mA cm−2 for the HER and OER, respectively. Besides, when it is used as a bifunctional electrocatalyst for overall water splitting, a low cell voltage of 1.55 V is needed to achieve a current density of 10 mA cm−2. This work provides new inspiration for developing other promising electrocatalysts based on the integration of various strategies.