Sulfur scrambling assisted in-situ growth of 3D-hierarchical FeNi2S4@Mo-doped Ni3S2/NF nanosheet arrays: A stellar performer towards alkaline water electrolysis

Industrial alkaline water electrolysis is facing major difficulties in developing inexpensive, abundant and active bifunctional non-noble metal electrocatalysts. Herein, a heterogeneous three-dimensional (3D) FeNi2S4@Mo-doped Ni3S2/NF heterostructure electrocatalyst is synthesized by a controlled two-step hydrothermal method. Based on the unique structural advantages, the number of redox active sites and the conductivity of the heter-ostructure electrode are improved remarkably resulting the shortening of ion diffusion path, effective penetration of the electrolyte and decrease in equivalent series resistance. The electrode achieves 10 mA cm-2 current density in hydrogen evolution reaction and oxygen evolution reaction at-121 and 150 mV overpotential, respectively in alkaline solution. The bifunctional electrochemical performance of the heterostructure is confirmed from the low cell voltage of 1.501 V and higher stability in overall water electrolysis. This work provides a useful strategy to tune the electrocatalytic performance by doping engineering and hetero-interface formation that offers an efficient self-supported 3D heterostructure electrode material for overall water electrolysis.

Automated summary

A heterostructure electrocatalyst with a three-dimensional FeNi2S4@Mo-doped Ni3S2/NF structure is successfully synthesized, achieving low overpotential and high stability in alkaline solution, providing a new electrode material for water electrolysis.