Electrochemical In Situ Self-Healing of Porous Nanosheets Based on the Phase Reconstruction of Carbonate Hydroxide to Layered Double Hydroxides with Unsaturated Coordination Metal Sites for High-Performance Water Oxidation

Abstract

The highly oxidized metal sites with unsaturated coordination derived from in situ electrochemical reconstruction combined with the dynamic adaptive surface geometry construction of the catalyst are of the utmost importance to enhance the intrinsic activity of the catalysts for oxygen evolution reaction (OER). Although the dynamic phase reconfiguration of catalysts during the OER process has been widely observed, the reconfigured active phase is only limited to the unitary metallic (oxygen) hydroxides. Here, we reveal the dynamic evolution of the local geometry and electronic structure of nickel–iron carbonate hydroxide hydrate (NFCH) electrodes under oxidation potential. The results show that, in the early stage of cyclic voltammetry (CV) cycles, the irreversible redox of Ni cations will lead to the phase transition of the porous NF-CH-O nanosheets (nickel ferrite (NFO) intercalated nickel–iron carbonate hydroxide hydrate), thus forming an intact NiFe layered double hydroxide (NF-LDH-O) nanosheets with high surface roughness, which has excellent OER catalytic activity and stability. The theoretical model indicates that the high-oxidation-state metal sites with unsaturated coordination formed by the electron transfer facilitated by the electronic coupling of nickel and iron (Ni–O–Fe bond) in the LDH phase can form appropriate bonds with the adsorbed oxygen species, thus accelerating the reaction rate and improving the OER activity of the NF-LDH-O catalyst. These discoveries not only clarify the electrochemical sensitivity of the NiFe-based carbonate hydroxide under oxidation conditions but also present an electrochemical coordination–engineering tactic for the rational design of high-active performance catalysts. This methodology for designing the high-performance electrocatalyst for renewable energy applications should be extended to other layered double hydroxide materials with different metal cations or interlayer anions.

Oxygen vacancies meet partial S substitution: an effective strategy to achieve obvious synergistic effects and adjustable electrochemical behavior in NiFe-LDH for enhanced OER and capacitive performance

“…Recently, transition metal-based electroactive materials (such as layered double hydroxides, 14,15 selenides 16,17 and nitrides 18,19 ) have been extensively applied in pseudocapacitors and OER due to their abundant redox active sites and suitable d-band center. 20,21 Among them, NiFe layered double hydroxide (NiFe-LDH) has gained significant attention because of the remarkable synergistic effect between nickel and iron, as well as the interlayer adjustable anions. [22][23][24] What's more, it is widely reported that NiFe-LDH materials follow the LOM during OER and possess a relatively negative redox potential window.…”

Strong coupling effect induced surface reconstruction of CeF3–Ni3N to form CeF3–NiOOH for the oxygen evolution reaction

“…32 Metalnitrides were also known to convert into the metal oxyhydroxide due to the surface reconstruction by anodic oxidation during the oxygen evolution reaction. [33][34][35] For instance, Schuhmann and his colleagues demonstrated that in situ generated CoOOH that has been obtained from Co 2 N can speed up the reaction kinetics for the OER. 36 However, due to the absence of oxygen-binding sites, the OER activity of nickel-based electrocatalysts is poor.…”

Curtailing the Excess eg-Orbital Filling of a Ni Atom by Enhanced Interatomic Charge Transfer within a Bimetallic 2D Metal–Organic Framework for the Oxygen Evolution Reaction

“…Nonetheless, the expensive price, paucity of reserves, and poor stability of these precious metal-based electrocatalysts have prevented large-scale commercial applications of the water electrolysis technique. − Furthermore, substantial overpotential to trigger the reaction reduces energy conversion efficiency and makes it difficult to use in devices for practical applications. On the other hand, two-dimensional (2D) nanomaterials like graphitic carbon nitride, transition metal oxides, layered double hydroxides, and transition metal dichalcogenides exhibit distinct chemical and physical properties. − Their huge lateral size, atomic thickness, large specific surface area, and high surface-to-volume atom ratio make them suitable for a wide range of applications including energy storage, electrocatalysis, electronics, sensors, and so on. These intriguing features and broad uses have also fueled researchers to fabricate 2D metal–organic framework (MOF) nanosheets.…”