Facile Synthesis of Medium‐Entropy Metal Sulfides as High‐Efficiency Electrocatalysts toward Oxygen Evolution Reaction

Abstract

Developing highly efficient and durable electrocatalysts toward oxygen evolution reaction (OER) is an urgent demand to produce clean hydrogen energy. In this study, a series of medium-entropy metal sulfides (MEMS) of (NiFeCoX) 3 S 4 (where X = Mn, Cr, Zn) are synthesized by a facile onepot solvothermal strategy using molecular precursors. Benefiting from the multiple-metal synergistic effect and the low crystallinity, these MEMS show significantly enhanced electrocatalytic OER activity compared with the binary-metal (NiFe) 3 S 4 and ternary-metal (NiFeCo) 3 S 4 counterparts. Especially, (NiFeCoMn) 3 S 4 delivers a low overpotential of 289 mV at 10 mA cm −2 , a decent Tafel slope of 75.6 mV dec −1 and robust catalytic stability in alkaline medium, outperforming the costly IrO 2 benchmark electrocatalyst and the majority of the reported metal sulfide-based electrocatalysts until now. These MEMS with facile synthesis and excellent electrocatalytic performance bring a great opportunity to design desirable electrocatalysts for practical application.

Sulfidation of CoCuOx Supported on Nickel Foam to Form a Heterostructure and Oxygen Vacancies for a High-Performance Anion-Exchange Membrane Water Electrolyzer

“…Similarly, the Ni 2p 1/2 peak at around 873 eV can be fitted into two peaks at 872.43 eV for Ni 2+ and 873.58 eV for Ni 3+ . The peaks at 861.33 and 879.29 eV are two satellite peaks . In Figure e, the chemical state of the sulfur shows two major peaks, in which the peak at 168.2 eV represents oxidized sulfur (SO 4 2– ) and the peak at 163 eV can be assigned to S-metal bonds and S 2– in S-CoCuO x /NF .…”

Activating Lattice Oxygen in High-Entropy LDH for Robust and Durable Water Oxidation

“…17 High-entropy materials (HEMs), such as high-alloy oxides, LDH, sulfides, and fluorides, are now emerging as a versatile platform for electrochemical OER due to their unique properties, including the high-entropy effect, cocktail effect, and sluggish diffusion effect. 18,19,20,21,22 Compared to traditional unitary, binary, and ternary OER electrocatalysts, HEMs exhibit similar catalytic activity but better stability 23 , which may be attributed to the entropy-stabilized effect and sluggish diffusion effect that prevent phase transition and metal leaching. 24 Motivated by these findings, we hypothesize that triggering lattice oxygen activation in HEMs electrocatalysts may enable to obtain both high activity and good stability that traditional LOM-based OER electrocatalysts can't do.…”

Ni2FeS4as a highly efficient earth-abundant co-catalyst in photocatalytic hydrogen evolution

“…56 Additionally, the nickel- and iron-based thiospinel shows a low overpotential for the OER in alkaline electrolytes. 55,57,58 The group of Apfel has successfully employed pentlandites, Fe 4.5 Ni 4.5 S 8 , for efficient electrocatalytic hydrogen evolution, with the partial replacement of sulphur by selenium further increasing the activity. 59–61…”

“…56 Additionally, the nickel-and iron-based thiospinel shows a low overpotential for the OER in alkaline electrolytes. 55,57,58 The group of Apfel has successfully employed pentlandites, Fe 4.5 Ni 4.5 S 8 , for efficient electrocatalytic hydrogen evolution, with the partial replacement of sulphur by selenium further increasing the activity. [59][60][61] Since co-catalysts are essentially electrocatalysts that additionally undergo efficient charge carrier exchange with the photocatalyst, we herein employed Ni 2 FeS 4 as a co-catalyst for the rst time to boost the hydrogen evolution activity of TiO 2 under sunlight irradiation.…”