Superior Alkaline Research Articles

Dual Cocatalytic Sites Synergize NiFe Layered Double Hydroxide to Boost Oxygen Evolution Reaction in Anion Exchange Membrane Water Electrolyzer

AbstractNickel‐iron layered double hydroxide (LDH) is a promising cost‐efficient catalyst to replace noble metals for alkaline oxygen evolution reaction (OER), yet its intrinsic activity under high current density conditions is not satisfactory, which greatly constrains the industrial application of NiFe LDH catalysts. Herein, a new class of integrated Co and W co‐doped NiFe LDH catalysts is reported with dual cocatalytic sites for alkaline OER catalysis. The optimized Co2.8, W3.8‐NiFe LDH integrated catalyst has superior alkaline OER activity (255 mV@1000 mA cm−2) and excellent catalytic stability (200 h@500 mA cm−2). The turnover frequency value of Co2.8, W3.8‐NiFe LDH can reach 4.02 s−1 at 1.49 V versus RHE, which is 9.6 times higher than that of NiFe LDH and superior to the noble metal catalysts. Moreover, it can achieve 1.0 A cm−2 at 1.86 V and maintain 300‐h stable operation in anion exchange membrane water electrolyzer. Theoretical and experimental studies indicate that W sites promote the *OH adsorption and Co sites favor protons desorption of OH*. These dual cocatalytic sites jointly promote *O coverage, effectively accelerating alkaline OER kinetic.

In situ hydrothermal growth of Ni-based hydrogen phosphate polyhedrons on Ni foam for efficient hydrogen evolution reaction

Developing a cost-effective and stable electrocatalyst is the key to achieve the large-scale applications of water electrolysis to produce green hydrogen. Herein, an in situ hydrothermal growth strategy was put forward to prepare a novel self-supporting electrode, that is, Ni-based hydrogen phosphate polyhedrons supported on 3D Ni foam. This electrode was composed of crystalline (Ni(H2PO4)2·2H2O, Ni(H3P2O7)2·2H2O), and amorphous phase in which NiO nanoparticles formed. The amorphous phase connected polyhedrons to the Ni foam substrate, forming multifarious heterogeneous interfaces. Such a structure possessed large number of active sites, favored the fast reaction kinetics and electron transport rate, synergistically resulting in a superior alkaline HER performance. In alkaline electrolyte, the electrode only needed a small overpotential of 69 mV to reach the current density of 10 mA cm−2 with a small Tafel slope of 56 mV dec−1, and exhibited a good stability at the current density of 100 mA cm−2 for 50 h. This in situ hydrothermal growth strategy opened up a new route to green synthesis of cost-effective and stable 3D heterostructured self-supporting electrode for water-splitting.

Zinc Assisted Thermal Etching for Rich Edge-Located Fe-N4 Active Sites in Defective Carbon Nanofiber for Activity Enhancement of Oxygen Electroreduction.

Single-atom catalysts (SACs) with edge-located metal active sites exhibit superior oxygen reduction reaction (ORR) performance due to their narrower energy gap and higher electron density. However, controllably designing such active sites to fully reveal their advantages remains challenging. Herein, rich edge-located Fe-N4 active sites anchored in hierarchically porous carbon nanofibers (denoted as e1-Fe-N-C) are fabricated via an in situ zinc-assisted thermal etching strategy. The e1-Fe-N-C catalyst demonstrates superior alkaline ORR activity compared to counterparts with fewer edge-located Fe-N4 sites and commercial Pt/C. Density functional theory calculations show that the accumulation of more negative charges near the Fe-N and the formation of partially reduced Fe state in the edge-located Fe-N4 sites reduce the energy barrier for the ORR process. Additionally, the unique hierarchically porous structures with mesopores and macropores facilitate full utilization of the active sites and enhance long-range mass transfer. The zinc-air battery (ZAB) assembled with e1-Fe-N-C has a peak power density of 198.9mWcm-2, superior to commercial Pt/C (152.3mWcm-2). The present strategy by facile controlling the amount of the zinc acetate template systematically demonstrates the superiority of edge-located Fe-N4 sites, providing a new design avenue for rational defect engineering to achieve high-performance ORR.

Structural elucidation of lignin, hemicelluloses and LCC from both bamboo fibers and parenchyma cells

Biomass recalcitrance, a key challenge in biomass utilization, is closely linked to the architectural composition and cross-linkages of molecules within cell walls. With three bamboo species investigated, this study aims to elucidate the inherent molecular-scale structural differences between bamboo fibers and parenchyma cells through a systematic chemical extraction and structural characterization of isolated hemicelluloses, lignin, and lignin-carbohydrate complexes (LCC). We observed that parenchyma cells exhibit superior alkaline extractability compared to fibers. Additionally, we identified the hemicelluloses in parenchyma cells as L-arabino-4-O-methyl-D-glucurono-D-xylan, displaying a highly branched structure, while that in fibers is L-arabino-D-xylan. Furthermore, the parenchyma cell lignin exhibited a higher syringyl-to-guaiacyl (S/G) ratio and β-O-4 linkage content compared to fibers, whereas fibers contain more carbon‑carbon linkages including β-β, β-5, and β-1. This notable structural difference suggests a denser and more stable lignin in bamboo fibers. Importantly, we found that LCC in parenchyma cells predominantly comprises γ-ester linkages, which exhibit an alkaline-unstable nature. In contrast, fibers predominantly contain phenyl glycoside linkages, characterized by their alkaline-stable nature. These findings were observed for all the tested bamboo species, indicating the conclusions should be also valid for other bamboo species, suggesting the competitiveness of bamboo parenchyma cells as a valuable biofuel feedstock.

Remarkable impact of chain backbone on the performance of Poly(norbornene derivatives)-based anion exchange membranes

Chemical stability and the trade-off between ion conductivity and dimensional stability are two primary challenges for the development of suitable anion exchange membranes (AEMs). Herein, a series of non-crosslinked poly(norbornene derivatives)-based AEMs containing a bulky steric hindrance hydrophobic arylene substituent were prepared by vinyl addition polymerization (VAP), ring-opening metathesis polymerization (ROMP), and ROMP followed post-hydrogenation, respectively. Compared with ROMP and hydrogenated type membranes, VAP-type membranes, especially the VAP-N-50, exhibited excellent dimensional stability with limited swelling ratio (SR = 27.9 %) while higher water uptake (WU = 213.8 %) at 80 °C, which is attributed to its rigid VAP-type cyclic chain backbone. Microtopography study demonstrated the existence of nanoscale phase separation in VAP-type AEMs and its association with water uptake and swelling behavior. VAP-N-60 showed excellent hydroxide conductivity up to 105.5 mS cm−1 at 80 °C, while exhibited superior alkaline stability that was not found in ROMP-type membrane ROMP-N-50 and the hydrogenated-type membrane H-ROMP-N-50. After being immersed in 2 M NaOH solution at 80 °C for 1200 h, the hydroxide conductivity loss of VAP-N-60 was only 3.0 %. Furthermore, a H2/O2 single cell using VAP-N-50 membrane achieved the highest peak power density of 722 mW cm−2 at 60 °C without back pressure.

MoS2 supported Ruthenium nanoparticles with abundant sulfur vacancies significantly improved hydrogen evolution reaction

The electrochemical hydrogen evolution reaction (HER) has become one of effective ways to produce hydrogen. MoS2 is a promising electrocatalyst for the HER, and loading noble metal atoms on MoS2 support can further enhance its HER activity. In present work, the CO was employed as a structure-directing agent to in situ synthesize MoS2-n (n = 0, 0.5, 1.0, 1.4 and 2.0 MPa, representing the CO pressure). Among them, the MoS2-1.4 with highest amounts of sulfur vacancies and superior alkaline HER performance was selected as the support for Ru loadings. Sulfur vacancies can stabilize Ru nanoparticles, prevent nanoparticles from aggregating, and facilitate the formation of small-sized nanoparticles. By optimizing the loading amounts of Ru, the 5Ru@MoS2-1.4 with the Ru loading of 5 wt.% and nanoparticle size of 2 nm exhibits the best alkaline HER activity by displaying a low overpotential of 55 mV and Tafel slope of 68.6 mV dec−1 at a current density of 10 mA cm−2 in 1.0 M KOH medium. This can be majorly related to the synergistic effect of MoS2-1.4 support and small-sized Ru nanoparticles, wherein the CO plays a significant role in regulating the structure of MoS2-1.4 support that favors dispersion of Ru nanoparticles. Generally, present work provides a strategy to enhance the HER catalytic performance of MoS2, which is favorable for other highly-efficient catalyst design.

Anion exchange membranes derived from poly(ionic liquid) of poly(bis-piperidinium) and polybenzimidazole blends

Anion exchange membranes (AEMs) play a critical role in various environmentally friendly electrochemical energy conversion and storage devices such fuel cells, water electrolysis and flow batteries. Recently, AEMs based on ether-free ionomers or ionenes have attracted much attention due to their excellent alkaline stabilities, however normally suffering from multiple-step synthetic procedure, post-functionalization and the use of precious metal catalysts. In this study, we develop a facile method to synthesize bis-piperidinium main-chain poly(ionic liquid)s devoid of ether linkages through the nucleophilic reaction between a bis-piperidine monomer of 4,4′-trimethylene bis(1-methyl-piperidine) and various bifunctional alkyl or aryl bromides. Seven poly(ionic liquid)s of poly(bis-alkyl piperidinium) are subsequently blended with polybenzimidazole (PBI) to give mechanically robust and dimensionally stable AEMs. The membrane performances are readily adjusted by changing the chemical structure of poly(bis-alkyl piperidinium)s. The membrane based on the poly(bis-alkyl piperidinium) containing a flexible butylidene spacer chain achieves the highest Br- conductivity of 67 mS cm−1 at 80 °C, tensile strength of around 13 MPa at room temperature, and a superior alkaline stability in 1 mol/L KOH at 60 °C during 1250 h. Density functional theory calculations further support the enhanced alkaline stability of the piperidinium cation with alkyl group compared with the one with benzyl group.

Gradient side chain grafted anion exchange membranes for fuel cell applications

This study reports on the synthesis, design and evaluation of a novel, interesting type of gradient-side-chain polyphenyl ether anion exchange membranes (AEMs) as the electrolytes for alkali fuel cells. Such membranes were fabricated by co-grafting of quaternized side chains with different lengths onto the polymer backbone. Based on our transmission electron microscopy and small angle X-ray scattering results, the gradient side chain structured AEM can enhance microphase and produce significantly larger ion clusters than that with purely long side chains; this is probably because the gradient side chain structure can possibly reduce the steric hindrance and facilitate cation aggregation during microphase separation. The gradient side chain AEM exhibited enhanced conductivity of hydroxide ions (107.7 mS cm−1 at 80 °C) compared to the uniform-side-chain membrane. It also demonstrated superior alkaline stability, retaining ca. 80% of conductivity and ion exchange capacity after a harsh alkali treatment at 80 °C in 1 M NaOH for 552 hours. Our study preliminarily demonstrates that gradient side chain structure is advantageous over conventional uniform side chains in promoting microphase separation of AEM, and deserves further investigations to optimize the gradient structure for better membrane performance.

Remodeling the Electronic Structure of Metallic Nickel and Ruthenium via Alloying in a Molecular Template for Sustainable Hydrogen Evolution.

The reasonably constructed high-performance electrocatalyst is crucial to achieve sustainable electrocatalytic water splitting. Alloying is a prospective approach to effectively boost the activity of metal electrocatalysts. However, it is a difficult subject for the controllable synthesis of small alloying nanostructures with high dispersion and robustness, preventing further application of alloy catalysts. Herein, we propose a well-defined molecular template to fabricate a highly dispersed NiRu alloy with ultrasmall size. The catalyst presents superior alkaline hydrogen evolution reaction (HER) performance featuring an overpotential as low as 20.6 ± 0.9 mV at 10 mA·cm-2. Particularly, it can work steadily for long periods of time at industrial-grade current densities of 0.5 and 1.0 A·cm-2 merely demanding low overpotentials of 65.7 ± 2.1 and 127.3 ± 4.3 mV, respectively. Spectral experiments and theoretical calculations revealed that alloying can change the d-band center of both Ni and Ru by remodeling the electron distribution and then optimizing the adsorption of intermediates to decrease the water dissociation energy barrier. Our research not only demonstrates the tremendous potential of molecular templates in architecting highly active ultrafine nanoalloy but also deepens the understanding of water electrolysis mechanism on alloy catalysts.

Creation of Cationic Polymeric Nanotrap Featuring High Anion Density and Exceptional Alkaline Stability for Highly Efficient Pertechnetate Removal from Nuclear Waste Streams.

There is an urgent need for highly efficient sorbents capable of selectively removing 99TcO4- from concentrated alkaline nuclear wastes, which has long been a significant challenge. In this study, we present the design and synthesis of a high-performance adsorbent, CPN-3 (CPN denotes cationic polymeric nanotrap), which achieves excellent 99TcO4- capture under strong alkaline conditions by incorporating branched alkyl chains on the N3 position of imidazolium units and optimizing the framework anion density within the pores of a cationic polymeric nanotrap. CPN-3 features exceptional stability in harsh alkaline and radioactive environments as well as exhibits fast kinetics, high adsorption capacity, and outstanding selectivity with full reusability and great potential for the cost-effective removal of 99TcO4-/ReO4- from contaminated water. Notably, CPN-3 marks a record-high adsorption capacity of 1052 mg/g for ReO4- after treatment with 1 M NaOH aqueous solutions for 24 h and demonstrates a rapid removal rate for 99TcO4- from simulated Hanford and Savannah River Site waste streams. The mechanisms for the superior alkaline stability and 99TcO4- capture performances of CPN-3 are investigated through combined experimental and computational studies. This work suggests an alternative perspective for designing functional materials to address nuclear waste management.

Empowering the Nickel Iron Oxyhydroxide through a Heterostructure Cocatalyst for Superior Alkaline and Saline Water Reduction

Empowering the Nickel Iron Oxyhydroxide through a Heterostructure Cocatalyst for Superior Alkaline and Saline Water Reduction

Oxophilic Ce single atoms-triggered active sites reverse for superior alkaline hydrogen evolution

The state-of-the-art alkaline hydrogen evolution catalyst of united ruthenium single atoms and small ruthenium nanoparticles has sparked considerable research interest. However, it remains a serious problem that hydrogen evolution primarily proceeds on the less active ruthenium single atoms instead of the more efficient small ruthenium nanoparticles in the catalyst, hence largely falling short of its full activity potential. Here, we report that by combining highly oxophilic cerium single atoms and fully-exposed ruthenium nanoclusters on a nitrogen functionalized carbon support, the alkaline hydrogen evolution centers are facilely reversed to the more active ruthenium nanoclusters driven by the strong oxophilicity of cerium, which significantly improves the hydrogen evolution activity of the catalyst with its mass activity up to −10.1 A mg−1 at −0.05 V. This finding is expected to shed new light on developing more efficient alkaline hydrogen evolution catalyst by rational regulation of the active centers for hydrogen evolution.

Unveiling the surface hydroxylation and selenite modification of in situ generated nickel for promoting the hydrogen evolution reaction

An electrochemical activation process for Ni–Se–O–H crystal has been found to produce a Ni/Ni(OH)2 heterostructure decorated with a small amount of SeO32−, exhibiting superior alkaline HER activity and durability.

Biomimetic Hydroxyapatite on 3D-Printed Nanoattapulgite/Polycaprolactone Scaffolds for Bone Regeneration of Rat Cranium Defects.

Nanoattapulgite (nano-ATP), a magnesium-aluminum silicate clay, can absorb substances and is a suitable material for bone repair and regeneration. In this study, using three-dimensional printing technology, a nano-ATP/polycaprolactone (PCL) scaffold was fabricated and modified using NaOH to form a rough surface. Biomimetic hydroxyapatite (HA) on nano-ATP/PCL scaffolds was fabricated using a biomineralized approach. The scaffold provided structural support through PCL and was modified with ATP and HA to improve hydrophilicity and promote the delivery of nutrients. The biocompatibility and osteogenic induction of scaffolds were assessed in vitro using mouse bone marrow mesenchymal stem cells. According to the in vitro study results, the nano-ATP/PCL/HA composite scaffold significantly boosted the expression levels of genes related to osteogenesis (p < 0.05), attributed to its superior alkaline phosphatase activity and calcium deposition capabilities. The outcomes of in vivo experimentation demonstrated an augmentation in bone growth at the rat cranial defect site when treated with the ATP/PCL/HA composite scaffold. It can be inferred from the results that the implementation of ATP and HA for the bone tissue engineering repair material displays encouraging prospects.

Fabrication of Self-Standing Porous Foam-like PdM (M = Ni, Fe, Co) Nanocrystals for Boosted Ethanol Oxidation Electrocatalysis

Rational designing of self-standing porous foam-like PdM (M = Ni, Fe and Co) nanocrystals was achieved by a fast aqueous-solution method via the co-reduction of metal precursors using sodium borohydride. This was based on the crystallites’ coalescence growth mechanism, including quick nucleation of Pd that served as starting seeds for the nucleation of M, which attached directly along the specific crystallographic and lowered its high surface energy by diffusion of PdM atoms across the interface via Brownian motion to afford self-standing porous foam-like PdM nanocrystals. Amongst the as-prepared PdM nanocrystals, PdNi nanocrystals showed a superior alkaline ethanol oxidation reaction (EOR) activity and stability compared to PdFe, PdCo, Pd nanospheres (Pd-NSs) and commercial Pd/C (10 wt.%) catalysts. The EOR mass activity of PdNi was 1.32, 1.51, 2.01 and 24.05 times than those of PdFe, PdCo, Pd-NSs and Pd/C, respectively based on equal Pd mass. This was attributed to the lower synergistic effect in PdNi, which enhanced H2O activation/dissociation to give OH- species needed for rapid EOR kinetics, meanwhile, the porous foam-like morphology improved electron mobility and increased accessible active sites. This study revealed that low synergism in porous PdM nanocrystals is beneficial for enhancing the EOR activity and durability, which may allow the design of other binary Pd-based alloys for various electrocatalytic reactions.

Insight into the Chemical Stability of N-Heterocyclic Ammonium Groups for Anion-Exchange Polyelectrolytes

The chemical stability of cationic groups, not only related to alkaline degradation but also to electrochemical degradation at high potentials, is the key factor that limits the durability of anion exchange membranes (AEMs) and anion exchange ionomers (AEIs) [1]. In recent years, quaternary ammonium (QA) groups represented by N-heterocyclic ammonium (NHA) groups display excellent ionic conductivity and superior alkaline stability, which makes NHA groups promising candidates to be applied in AEMs and AEIs [2]. However, electrochemical degradation of NHA groups has been neglected in previous research, even though the electrochemical oxidation of phenyl QAs was found in the ionomer at the oxygen evolution potentials [3]. In short, the mechanism by which effect of substituents affects the durability of NHAs cations, including alkaline stability and electrochemical stability, is unclear yet, and NHA groups must be attached to the polymer backbones by substituents to achieve their applications.In this work, the chemical stability of NHA is comprehensively studied. To investigate the relationship between alkaline durability and structure, we report a systematic study on the alkaline stability of 24 representative NHA groups at different hydration numbers (λ). The electronic effect of substituents on NHA groups and degradation mechanisms of NHA groups are systematically investigated by 1H nuclear magnetic resonance (1H NMR) and density functional theory (DFT) calculations, showing that the NHA groups with electron-donating substituents exhibit outstanding alkaline stability and linking NHA groups with the polymer backbone via γ-position could be a rational design for highly alkaline stable AEMs and AEIs. Furthermore, a constant voltage is applied to the QAs electrolyte solution to measure the electrochemical stability by simulating the real operating environment of and AEM water electrolyzers. Compared to structural changes before and after voltage application, NHA exhibits worse stability than alkyl QAs, involving the radical degradation and electrochemical degradation. These results above give us a clearer picture while designing the polymer used for electrochemical devices, which is that a careful balance needs to be established between alkaline and electrochemical durability, especially under the high potential and harsh alkaline environment.

Heterogeneous Cu incorporated into Ni6Fe2-LDH/rGO induces spin exchange interaction to enhance alkaline hydrogen evolution

The efficiency of hydrogen evolution reaction (HER) takes an important influence on electrochemical water electrolysis, yet it still delivers sluggish kinetics mainly due to the high kinetic energy barriers. Herein, Cu1Ni5Fe2-Layered double hydroxides/reduced graphene oxide (denoted as Cu1Ni5Fe2-LDHs/rGO) with heterogeneous Cu atoms incorporated into Ni6Fe2-LDHs/rGO is constructed through a hydrothermal method and doping strategy in this works, wherein the subtle lattice distortion is availably regulated and optimized by Cu2+ Jahn-Teller effect, offering more active sites for HER. As benefits of the subtle lattice distortion and the spin exchange interaction, Cu1Ni5Fe2-LDHs/rGO displays ferromagnetism at room temperature and shows superior alkaline HER properties with a relatively low overpotentials of 50 mV at 10 mA cm−2 in 1.0 M KOH. The low Tafel slope of 38 mV dec−1 implies Cu1Ni5Fe2-LDHs/rGO owns an ultra-fast HER kinetic. This study can offer a new strategy to construct high efficient HER catalysts based on transition metal NiFe-LDHs.

Constructing Heterogeneous Interface by Growth of Carbon Nanotubes on the Surface of MoB2 for Boosting Hydrogen Evolution Reaction in a Wide pH Range.

Transition metal diborides represented by MoB2 have attracted widespread attention for their excellent acidic hydrogen evolution reaction (HER). Nevertheless, their electrocatalytic performance is generally unsatisfactory in high-pH electrolytes. Heterogeneous interface engineering is one of the most promising methods for optimizing the composition and structure of electrocatalysts, thereby greatly affecting their electrochemical performance. Herein, a heterostructure, composed of MoB2 and carbon nanotubes (CNTs), is rationally constructed by boronizing precursors including (NH4 )4 [NiH6 Mo6 O24 ]·5H2 O (NiMo6 ) and Co complexes on the carbon cloth (Co,Ni-MoB2 @CNT/CC). In this method, NiMo6 is boronized to form MoB2 by a modified molten-salt-assisted borothermal reduction. Meanwhile, Co catalyzes extra carbon sources to grow CNTs on the surface of MoB2 . Thanks to the successful production of the heterostructure, Co,Ni-MoB2 @CNT/CC exhibits remarkable HER performance with a low overpotential of 98.6, 113.0, and 73.9mV at 10mAcm-2 in acidic, neutral, and alkaline electrolytes, respectively. Notably, even at 500mAcm-2 , the electrochemical activity of Co,Ni-MoB2 @CNT/CC exceeds that of Pt/C/CC in an alkaline solution and maintains over 50h. Theoretical calculations reveal that the construction of theheterostructure is beneficial to both water dissociation and reactive intermediate adsorption, resulting in superior alkaline HER performance.

Regulating Pt electronic properties on NiFe layered double hydroxide interface for highly efficient alkaline water splitting

Developing cost-effective and highly efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrocatalysts is imperative for catalyzing water electrolysis. In this study, significant change in Pt electronic properties was conducted on NiFe layered double hydroxide (NiFe-LDH) by simply regulating the order of boron-modification and Pt-deposition, thereby achieving two electrocatalysts of B-Pt-NiFe-LDH with major Pt0 species and Pt-B-NiFe-LDH with Pt2+ species as the main component, respectively. Interestingly, the B-Pt-NiFe-LDH electrocatalyst displays better alkaline OER performance with a smaller overpotential (208 mV) at 100 mA cm−2 than Pt-B-NiFe-LDH (229 mV), while the Pt-B-NiFe-LDH electrocatalyst shows superior alkaline HER performance with only 19 mV overpotential at 10 mA cm−2 compared with that of B-Pt-NiFe-LDH (65 mV) and Pt-NiFe-LDH (28 mV). The corresponding electrolyzer of B-Pt-NiFe-LDH//Pt-B-NiFe-LDH in 1 M KOH requires only a very low voltage of 1.475 V to deliver 10 mA cm−2 with good durability (110 h), which exceeds the performance of the widely studied RuO2//Pt/C cell (1.516 V). Density functional theory (DFT) calculations suggest that the Pt0 species on NiFe-LDH can lower the energy barrier for OER, while the Pt2+/4+ components are beneficial for HER. This work demonstrates the rational strategy to regulate electronic properties on electrocatalysts for highly efficient water-splitting.

Interfacial interaction of amorphous NiFe hydroxide/graphene composites elevating the oxygen evolution catalytic performance

Ni-based amorphous transition metal catalysts have gained considerable research attention owing to their superior alkaline oxygen evolution performance compared to their crystalline counterparts. In this work, we prepared amorphous NiFe/graphene composites via the solvothermal method. By regulating the ratio of components, the composite catalyst exhibited an exceptionally low overpotential of 231 mV at a current density of 10 mA cm−2 and maintained stable catalytic behavior for 100 h at this current density. Electrochemical analysis and differential charge density diagrams revealed the presence of charge transport at the interface of the heterogeneous structure, greatly increasing the intrinsic activity of the material. Additionally, pH dependence on the catalytic activity suggested a decoupled proton-electron transfer (PT/ET) pathway, and chemical deprotonation is identified as the rate-limiting step in the catalytic reaction. These findings provide critical insights and reliable data to facilitate future research on improving the oxygen evolution performance of NiFe-based amorphous catalysts.