Designing an Fe^III-Doped Nickel Sulfide/Carbon Nanotube Hybrid Catalyst for Alkaline Electrolyte Membrane Water Electrolyzers and Zn–Air Battery Performances

Abstract

The development of an electrocatalyst with high performance using nonprecious metals/metal oxides as well as its applications in flexible and rechargeable Zn−air batteries and water electrolyzers is in strong demand from industries. In this study, we have designed and synthesized a new (Fe 3 NiS 8−δ ) −4+δ carbon nanotube (CNT) hybrid electrocatalyst and revealed that the catalyst shows a very high oxygen evolution reaction (1.55 V at 10 mA/cm 2 ) and oxygen reduction reaction (E 1/2 = 0.82 V vs RHE) performances. Based on the analyses by in situ electrochemical X-ray diffraction together with structure analysis software, in situ electrochemical Fourier transform infrared spectroscopy, transmission electron microscopy, and computer simulations, such a high performance is derived from the sulfur vacancies that were formed via the self-doped d−p orbitals of Fe III in (Fe 3 NiS 8−δ ) −4+δ . Here, we describe an adequate explanation about the role of the iron doping in the nickel sulfides in the catalyst. Furthermore, the fabricated flexible and rechargeable Zn−air and water electrolyzer batteries using the catalyst show a low charge−discharge overpotential gap of 0.66 V and a 237 mA/cm 2 current density at 1.9 V, which is very important for the development of a rechargeable Zn−air battery and water electrolyzer with a high performance. First-principles calculations are employed to investigate the reaction mechanisms and elucidate the effect of the CNT support for the catalytic activity.

Facile Construction of Carbon Encapsulated of Earth‐Abundant Metal Sulfides for Oxygen Electrocatalysis

“…The above results verified the outstanding stability and strong anti‐methanol poison of Co−S‐700. This is in agreement with the previous reports: the appropriate strength of the adsorption energy ΔE o✶ for CoS x contribute to the good intrinsic activity, [33] and the improved performance also illustrate the synergistic effect between sulfide and carbon layer as certified previous research (facilitating the cleavage of the O−O bond with a low activation barrier) [34,35] …”

Coordination Polymer-Derived Fe3N Nanoparticles for Efficient Electrocatalytic Oxygen Evolution

“…The reaction free energies of reactions – are denoted as Δ G 1 – ΔG 4 . For free-energy calculation details, the reader can refer to the previous reports; ,− please see the Supporting Information. The theoretical overpotential η is obtained according to eq …”

Cation Modulation of Cobalt Sulfide Supported by Mesopore-Rich Hydrangea-Like Carbon Nanoflower for Oxygen Electrocatalysis

“…The electrochemical performance of Ni 0.14 -Co 9 S 8 @HCF-24 is also comparable to those of most of the transition-metal chalcogenides reported before (Table S2). ,,,,,,− A specific capacity of 783 mAh g –1 normalized by the zinc mass is achieved using the Ni 0.14 -Co 9 S 8 @HCF-24 cathode at 5 mA cm –2 , while there is only 727 mAh g –1 for the Pt/C + RuO 2 cathode (Figure d). The rate capability performance was studied at 1–10 mA cm –2 .…”