Phosphorus and Fluorine Co‐Doping Induced Enhancement of Oxygen Evolution Reaction in Bimetallic Nitride Nanorods Arrays: Ionic Liquid‐Driven and Mechanism Clarification

Abstract

Electrocatalytic splitting of water is becoming increasingly crucial for renewable energy and device technologies. As one of the most important half-reactions for water splitting reactions, the oxygen evolution reaction (OER) is a kinetically sluggish process that will greatly affect the energy conversion efficiency. Therefore, exploring a highly efficient and durable catalyst to boost the OER is of great urgency. In this work, we develop a facile strategy for the synthesis of well-defined phosphorus and fluorine co-doped Ni Co N hybrid nanorods (HNs) by using ionic liquids (ILs; 1-butyl-3-methylimidazolium hexafluorophosphate). In comparison to the IrO catalyst, the as-obtained PF/Ni Co N HNs manifests a low overpotential of 280 mV at 10 mA cm , Tafel slope of 66.1 mV dec , and excellent durability in 1.0 m KOH solution. Furthermore, the iR-corrected electrochemical results indicate it could achieve a current density of 100 mA cm at an overpotential of 350 mV. The combination of cobalt and nickel elements, 1D mesoporous nanostructure, heteroatom incorporation, and ionic liquid-assisted nitridation, which result in faster charge transfer capability and more active surface sites, can facilitate the release of oxygen bubbles from the catalyst surface. Our findings confirm that surface heteroatom doping in bimetallic nitrides could serve as a new class of OER catalyst with excellent catalytic activity.

Cobalt Nickel Nitrogen Array as a Easily Eecoverable, Effective Catalyst for Liquid‐Phase Catalytic Reaction with Remarkable Recycled Stability

“…After nitridation at 450 °C, the NiCo precursor/NF can be converted into NiCoN/NF‐450, which is considered as a non‐metal catalyst . The formation of NiCoN/NF‐450 is verified by XRD, SEM, TEM and X‐ray photoelectron spectroscopy (XPS).…”

Nickel‐Based Transition Metal Nitride Electrocatalysts for the Oxygen Evolution Reaction

“…Another compositionalvariation that has been brought about is through the addition of elements. [52] For ternary NiFe nitrides in particular, the electrocatalytic properties (200 mV overpotential, 40 mV Tafel slope,1 .34 Vonset potential) are further enhanced when compared to those of pure Ni 3 N( 250 mV overpotential, 45 mV Tafel slope, 1.55 Vonset potential). Chen et al [50] compared the intrinsic conductivity of cobalt nitrides (Co 2 N, Co 3 N, and Co 4 N), comes from electron delocalization modulation, and the OER efficiency.I nC o 4 N, as Nc ontent decreases, intrin-sic conductivity increases, which correlatesw ith improved OER efficiency and stability in alkaline (KOH) solution.A lloying or doping can also improve the electrical properties of materials, and hence their combined effect further enhances the OER.…”

“…[51] To improve OER activity, anion doping is also effective for TMNs. [52] For ternary NiFe nitrides in particular, the electrocatalytic properties (200 mV overpotential, 40 mV Tafel slope,1 .34 Vonset potential) are further enhanced when compared to those of pure Ni 3 N( 250 mV overpotential, 45 mV Tafel slope, 1.55 Vonset potential). Other TMNs, such as NiCo 2 N( 180 mV overpotential,1 .32 Vo nset potential, 55 mV Ta fel slope), [53] NiMoN/CF (210 mV overpotential, 1.32 Vo nset potential, 55 mV Tafel slope), [54] and Ni 3 MnN (320 mV overpotential, 1.60 Vo nsetp otential, 64 mV Ta fel slope) [55] have also been studied for the OER.…”

Transition‐Metal Oxides/Carbides@Carbon Nanotube Composites as Multifunctional Electrocatalysts for Challenging Oxidations and Reductions

“…Developing new,e fficient bifunctionalO ER/ORR electrocatalysts based on earth-abundant materials is therefore crucial for the future deployment of these technologies. [12][13][14][15][16][17][18] Currently,t hese materials are still hampered by their low electricalc onductivity and their fast degradation due to irreversible redox processes on the surfaceo ft he material. [8][9][10][11] Recently,t ransition-metalo xidesa nd carbides have been put forward as alternative ORRa nd OER electrocatalysts that can show catalytic performance similar to noble metals.…”

“…[8][9][10][11] Recently,t ransition-metalo xidesa nd carbides have been put forward as alternative ORRa nd OER electrocatalysts that can show catalytic performance similar to noble metals. [12][13][14][15][16][17][18] Currently,t hese materials are still hampered by their low electricalc onductivity and their fast degradation due to irreversible redox processes on the surfaceo ft he material. One approach to overcome these issues is the design of nanostructured composites in which the reactive transition-metal oxideso rc arbidesa re electrically "wired" to conductive carbons ubstrates;t his leads to high-performance electrocatalysts, for example, for ORR and/or OER.…”