Amorphous Oxysulfide Reconstructed from Spinel NiCo₂S₄ for Efficient Water Oxidation

Abstract

The progress of effective and durable electrocatalysts for oxygen evolution reaction (OER) is urgent, which is essential to promote the overall efficiency of green hydrogen production. To improve the performance of spinel cobalt‐based oxides, which serve as promising water oxidation electrocatalysts in alkaline electrolytes, most researches have been concentrated on cations modification. Here, an anionic regulation mechanism is employed to adopt sulfur(S) anion substitution to supplant NiCo2O4 by NiCo2S4, which contributed to an impressive OER performance in alkali. It is revealed that the substitution of S constructs a sub‐stable spinel structure that facilitates its reconstruction into active amorphous oxysulfide under OER conditions. More importantly, as the active phase in the actual reaction process, the hetero‐anionic amorphous oxysulfide has an appropriately tuned electronic structure and efficient OER electrocatalytic activity. This work demonstrates a promising approach for achieving anion conditioning‐based tunable structure reconstruction for robust and easy preparation spinel oxide OER electrocatalysts.

1D@2D Hierarchical NiCo2O4@MIL-53(Fe) Nanostructures Synergistically Enhance Oxygen Evolution Reaction

“…HRTEM revealed heterogeneous structures (Figure b). Moreover, the HRTEM images (Figure c,d) showcase clear lattice fringes with crystal plane spacings of 0.285 and 0.247 nm, matching the (220) and (311) planes of NiCo 2 O 4 , respectively. , It is worth noting that MIL-53­(Fe)’s corresponding lattice fringes and diffraction spots were not visible in HRTEM. This can be attributed to the inherent challenges in extracting such information in TEM due to the distinctive properties of MOFs, consistent with prior research. − Additionally, the SAED patterns recorded from NiCo 2 O 4 show weak diffraction spots which can be assigned to the deposition of MIL-53­(Fe) onto the NiCo 2 O 4 surface, causing a reduction in electron energy (Figure e) …”

“…Moreover, the HRTEM images (Figure 3c,d) showcase clear lattice fringes with crystal plane spacings of 0.285 and 0.247 nm, matching the (220) and (311) planes of NiCo 2 O 4 , respectively. 9,22 It is worth noting that MIL-53(Fe)'s corresponding lattice fringes and diffraction spots were not visible in HRTEM. This can be attributed to the inherent challenges in extracting such information in TEM due to the distinctive properties of MOFs, consistent with prior research.…”

Prominent development of Ni-based oxygen-evolving electrocatalysts for water splitting

“…18,97,98 Martirez and Carter investigated the doping effects of selected 3d and 4d transition metals on a β-NiOOH catalyst for OER using DFT calculations, suggesting that Co is a promising alternative dopant to Fe; however, with only 0.07 V higher thermodynamic overpotential predicted. 82 Recently, various types of NiCo catalysts for OER have been reported including NiCo oxides, 97,99 spinel NiCo 2 O 4 , 100 NiCo LDH, 101 NiCo MOFs, 102–104 NiCo phosphides, 105,106 NiCo sulfides, 107,108 NiCo carbonate hydroxide hydrate, 109 NiCo nitrides, 110 NiCo oxalates, 111 and NiCo alloys. 112…”

“…9). 107 The crystalline NiCo 2 S 4 nanoneedle arrays were prepared on an NF electrode via a hydrothermal method. CVs of NiCo 2 S 4 and pristine NiCo 2 O 4 were measured in a 1.0 M KOH solution.…”

Electrodeposited Multimetal Alloyed NiMoCo on Ni Mesh for Efficient Alkaline Hydrogen Evolution Reaction

“…Hydrogen is an important clean energy source that solves the energy crisis and achieves decarbonization. − Alkaline water electrolysis (AWE) hydrogen production is one of the most mature and widely used hydrogen production technologies in the industry today. , Although AWE has encountered new opportunities in today’s society for green hydrogen production, it still needs high operating cell voltages along with high electricity energy input. The development of industrial-scale electrocatalysts suitable for industrial applications is of great significance to extend the service life of AWE and reduce preparation, operation, and postmaintenance costs .…”