Rhenium induced electronic structure modulation of Ni3S2/N-doped graphene for efficient trifunctional electrocatalysis

Abstract

Herein, we develop a free-standing trifunctional and durable electrocatalyst integrating the Re-doped Ni 3 S 2 nanoarray on N-doped graphene (NG) modified nickel foam substrate (Re–Ni 3 S 2 /NG/NF). Particularly, Re-doping is proven to modify the local electronic structure, increase the electroactive surface area, and optimize the adsorption energies of Ni 3 S 2 , greatly enhancing trifunctional activities. Accordingly, the water electrolyzer based on the symmetric Re–Ni 3 S 2 /NG/NF electrodes achieves a small cell voltage of 1.58 V at 10 mA cm −2 and high Faradaic efficiency of ∼97%, exceeding Pt/C + IrO 2 counterpart. Moreover, the rechargeable Zn–air battery with the Re–Ni 3 S 2 /NG/NF leads to achieve a high power density of 99 mW cm −2 and round-trip efficiency of 71.2% with a long term stability of 5000 cycles. Taking full potential of Re–Ni 3 S 2 /NG/NF electrocatalysts used as “all-in-one” electrode, a real-life operation of self-powered water splitting system is demonstrated for practical applications into highly efficient and multifunctional renewable energy systems. The Re-doped Ni 3 S 2 nanoarray is designed and integrated on N-doped graphene modified nickel foam substrate as an efficient and robust trifunctional electrocatalyst for both water splitting and rechargeable Zn–air battery. Experimental and theoretical analyses demonstrate that the Re doping endows the Re–Ni 3 S 2 modulated electronic structural configuration and optimized chemisorption energy toward intermediates, which synergistically boosts the trifunctional electrocatalytic activity. • Re-doping induces the lattice distortion and surface deformation of Ni 3 S 2 . • Re–Ni 3 S 2 /NG/NF exhibits excellent trifunctional activities for HER/OER/ORR. • The Re–Ni and Ni–Ni bridge, Re–Ni bridge, and NG are trifunctional active sites. • Re–Ni 3 S 2 /NG/NF serves as electrodes for both water electrolyzer and Zn–air battery. • Highly efficient Zn–air battery powered water splitting system is demonstrated.