Heterogeneous FeNi2S4/Ni3S4 nanoparticles embedded CNT networks for efficient and stable water oxidation

Abstract

Development of efficient and reliable transition metal-based oxygen evolution reaction (OER) catalysts has profound implications to achieve carbon-neutral economy in the future. Herein, a novel hybrid OER catalyst of heterogeneous FeNi 2 S 4 /Ni 3 S 4 nanoparticles embedded CNT networks (FeNi 2 S 4 /Ni 3 S 4 @CNT) was prepared by a facile one-step hydrothermal reaction. The ultrafine heterogeneous nanoparticles of FeNi 2 S 4 and Ni 3 S 4 embedded CNT can expose abundant active sites and enhance the electrochemically active area; the electronic structure modulated by the bi-metallization of FeNi 2 S 4 via partial substitution of Ni with Fe; the robust contact between conductive FeNi 2 S 4 and Ni 3 S 4 nanoparticles with abundant active sites on the surface and the CNT network with high conductivity can effectively promote the electron transfer; the 3D network with rich nanopores is beneficial to electrolyte penetration and gas release. These above merits and synergistic effects of FeNi 2 S 4 and Ni 3 S 4 endow the catalyst superior OER performances with an ultralow overpotential of 247 mV for the current density of 10 mA cm −2 , a low Tafel slope of 53.7 mV dec −1 and remarkable durability over 20 h, surpassing those of commercial OER catalyst RuO 2 . This work provides a synergistic OER boosting strategy via bi-metallization, heterogeneous nanoparticle distribution and conductive skeleton to develop non-precious-based electrocatalyst by a facile one-pot synthesis method. • FeNi2S4/Ni3S4 embedded CNT networks were synthesized by solvothermal reaction. • FeNi2S4/Ni3S4@CNT exhibits superior OER performance and long-term stability. • Good OER activity is due to the unique nanoarchitecture and synergistic effect.