Atomic Doping and Anion Reconstructed CoF₂ Electrocatalyst for Oxygen Evolution Reaction

Abstract

limits the availability of new types of energy. [4] Accordingly, hydrogen has been considered as a promising energy carrier to storage renewable energy through electrocatalytic water splitting. Great progress has been achieved to improve the electrolytic efficiency of the hydrogen evolution reaction (HER) [5,6] and oxygen evolution reaction (OER). [7,8] For HER, many nonnoble metal compounds have replaced traditional noble metal catalysts and have been utilized with satisfying catalytic efficiency. [9][10][11][12] Concerning to the fourelectron OER process, its reaction rates determine the overall catalytic efficiency of the water electrolysis. [13][14][15] Therefore, it is of particular importance to develop OER catalysts with high activity and durability.At present, noble metal-based materials for OER, such as ruthenium oxides, are still ranking the highest level. [16,17] Meanwhile, nonnoble metal compounds, for instance, transition metal oxides, [18][19][20][21] perovskite, [22,23] hydroxide, [24,25] nitrides, [26,27] borates, [28,29] and so on, have also captured extensive interests for preparing high-efficient OER catalysts. Among them, the metal fluoride, mostly literature reported for supercapacitor, lithium ion battery, etc., [30][31][32][33] is rarely wielded in the field of water electrolysis, possibly due to the chemical/electrochemical instability of fluoride ions and the weak bond between the metal ions and fluoride ions. Actually, fluoride ions can be easily replaced by other anions during the testing process, which is beneficial to optimize the catalytic activity by anionic reconstruction. [34] Consequently, metal fluoride is one of the most promising candidates to enhance the OER activity. Cobalt-based compounds, high-efficient catalytic activity for OER, have been considered one of the most prospective nonnoble catalysts in alkaline conditions for their low cost, rich source, and excellent corrosion resistance. [35][36][37][38][39] In addition, atomic doping or substitution can further improve its electrocatalytic performance by introducing more defects and catalytic active sites. [40][41][42] Herein, we took Fe-doped CoF 2 as research object to explore its electrocatalytic performance and catalytic mechanism in water splitting. Pristine CoF 2 was fabricated through a facile two-step reaction of hydrothermal method and chemical vapor deposition fluorination process. Furthermore, Fe 3+ was introduced into the resultant by adding iron agent into the precursor solution. The obtained Fe-doped CoF 2 revealed better electrocatalytic performance compared to pristine CoF 2 in 1 m Electrocatalytic water splitting is one of the most promising green solutions for large-scale hydrogen production, which has developed rapidly in recent years. The slow reaction rate of oxygen evolution reaction (OER) has become the bottleneck to improve the electrocatalytic efficiency. Herein, Fe-doped CoF 2 nanowire arrays on 3D nickel foam are prepared by two steps of hydrothermal reaction and fluorination process. The increa...

Electrode Materials of Cobaltous Fluoride for Supercapacitor and Electrocatalysis Applications

“…The core‐level F 1s spectrum is fitted by only one peak at 684.7 eV. This is consistent with the reported literature [35–37] …”

Tuning Co2+ Coordination in Cobalt Layered Double Hydroxide Nanosheets via Fe3+ Doping for Efficient Oxygen Evolution

“…With the rapid development of renewable energy technologies, such as metal-air batteries, fuel cells, and other energy storage areas, the reversible conversion between oxygen and water is becoming more vital in the process of value-added opto/electrocatalysis reaction. − The oxygen/water cycling includes two important parts: oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which are also the foundation of metal-air batteries and full cells theoretially. , Oxygen evolution reaction, as a serious reaction obstacle to the development and application of electrocatalytic fields, is a four-electron transfer reaction with sluggish kinetics and high overpotential. It is important and urgent to explore efficient electrocatalysts in the application of OER. − At present, iridium oxide (IrO 2 ) and ruthenium oxide (RuO 2 ) are the most active OER electrocatalysts applied, which exhibit excellent OER properties in both acidic and alkaline media. − However, the high cost limits their wide application and the development of related energy conversion processes. Therefore, it is crucial to develop high-efficiency, high-stability electrocatalysts with low cost for the promotion of oxygen evolution reaction. − …”

Kinetic Regulation Engineering and In‐Situ Spectroscopy Studies on Transition‐Metal‐Based Electrocatalysts for Water Splitting

“…These heterostructures in situ make a tight connection between the parent metal CoNi Fe 3 N and the newly formed CoNi FeOOH, ensuring excellent electrical conductivity. Dong et al [78] . prepared Fe doped CoF 2 nanowire arrays on three‐dimensional nickel foam.…”

“…These heterostructures in situ make a tight connection between the parent metal CoNi Fe 3 N and the newly formed CoNi FeOOH, ensuring excellent electrical conductivity. Dong et al [78] prepared Fe doped CoF 2 nanowire arrays on three-dimensional nickel foam. The experimental results show that the increase in catalytic active sites and the accelerated charge transfer rate enable the self-supported Fe doped CoF 2 electrode to exhibit excellent OER performance in alkaline electrolytes.…”