Enhanced Oxygen Evolution Reaction Activity Research Articles

Spectroscopic Investigations of Complex Electronic Interactions by Elemental Doping and Material Compositing of Cobalt Oxide for Enhanced Oxygen Evolution Reaction Activity

AbstractDoping and compositing are two universal design strategies used to engineer the electronic state of a material and mitigate its disadvantages. These two strategies are extensively applied to design efficient electrocatalysts for water splitting. Using cobalt oxide (CoO) as a model catalyst, it is proven that the oxygen evolution reaction (OER) performance can be progressively improved, first by Fe‐doping to form Fe‐CoO solid solution, and further by the addition of CeO2 to produce a Fe‐CoO/CeO2 composite. X‐ray absorption spectroscopy (XAS) reveals that distinct electronic interactions are induced by the processes of doping and compositing. Fe‐doping of CoO can break down the structural symmetry, changing the electronic structure of both Co and O species at the surface and decreasing the flat‐band potential (Vfb). In comparison, subsequent compositing of Fe‐CoO with CeO2 induces negligible electronic changes in the Fe‐CoO (as seen in ex situ characterizations), but significantly modifies the oxidative transformations of both Co and Fe under OER conditions. The spectroscopic investigations reveal that Fe‐doping and CeO2 compositing play different roles in modifying the electronic properties of CoO in its pristine state and during OER catalysis, in return, providing useful guidance for the design of more efficient electrocatalysts using these two strategies.

Enhancing the oxygen evolution reaction activity of Iron (oxy)hydroxide by increasing reactive sites with morphology modulation

Nonprecious transition metal (oxy)hydroxides play a vital role in accelerating the kinetics of sluggish oxygen evolution reaction (OER). The fast electron transfer from the electrocatalyst material surface to the electrode is key to obtaining improved OER activity in terms of improved reaction kinetics and reduced overpotential. Therefore, it is highly desirable to design electrocatalysts with efficient electron transport properties. Here, an approach of modulation of the morphology of Iron (oxy)hydroxide through the incorporation of Cr is used to obtain high electrocatalytic activity. The incorporation of Cr resulted in the modified morphology of Iron (oxy)hydroxide with the formation of a porous pit-like structure which offers large reactive sites to effectively adsorb the reactants and allow an efficient electron transfer pathway from electrocatalyst to circuit through Ni foam electrode. A 50 % Cr incorporated electrocatalyst (Fe5.0Cr5.0 (oxy)hydroxide) exhibits excellent OER activity with an overpotential of 237 mV and 297 mV at current densities of 10 and 100 mA cm─2, respectively owing to fast electron transport from electrocatalyst to substrate due to formation of porous pit-like structure. Furthermore, Fe5.0Cr5.0 electrocatalyst shows high durability of over 100 h at 10 mA cm─2. The enhanced OER activity is attributed to the effect of Cr incorporation and morphology modulation which helps to modulate the electronic structure as well as electrocatalytic active sites of Fe (oxy)hydroxide. The systematic incorporation and modulation of morphology pave the way for designing future electrocatalysts for various electrochemical activities.

Balance between FeIV-NiIV synergy and Lattice Oxygen Contribution for Accelerating Water Oxidation.

Hydrogen obtained from electrochemical water splitting is the most promising clean energy carrier, which is hindered by the sluggish kinetics of the oxygen evolution reaction (OER). Thus, the development of an efficient OER electrocatalyst using nonprecious 3d transition elements is desirable. Multielement synergistic effect and lattice oxygen oxidation are two well-known mechanisms to enhance the OER activity of catalysts. The latter is generally related to the high valence state of 3d transition elements leading to structural destabilization under the OER condition. We have found that Al doping in nanosheet Ni-Fe hydroxide exhibits 2-fold advantage: (1) a strong enhanced OER activity from 277 mV to 238 mV at 10 mA cm-2 as the Ni valence state increases from Ni3.58+ to Ni3.79+ observed from in situ X-ray absorption spectra. (2) Operational stability is strengthened, while weakness is expected since the increased NiIV content with 3d8L2 (L denotes O 2p hole) would lead to structural instability. This contradiction is attributed to a reduced lattice oxygen contribution to the OER upon Al doping, as verified through in situ Raman spectroscopy, while the enhanced OER activity is interpreted as an enormous gain in exchange energy of FeIV-NiIV, facilitated by their intersite hopping. This study reveals a mechanism of Fe-Ni synergy effect to enhance OER activity and simultaneously to strengthen operational stability by suppressing the contribution of lattice oxygen.

Dual Doping of B and Fe Activated Lattice Oxygen Participation for Enhanced Oxygen Evolution Reaction Activity in Alkaline Freshwater and Seawater

AbstractThe exploitation of highly activity oxygen evolution reaction (OER) electrocatalysts is critical for the application of electrocatalytic water splitting. Triggering the lattice oxygen mechanism (LOM) is expected to provide a promising pathway to overcome the sluggish OER kinetics, however, effectively enhancing the involvement of lattice oxygen remains challenging. In this study, the fabrication of B, Fe co‐doped CoP (B, Fe─CoP) nanofibers is reported, which serve as highly efficient OER electrocatalyst through phosphorization and boronation treatment of Fe‐doped Co3O4 nanofibers. Experimental results combined with theoretical calculations reveal that simultaneous incorporation of both B and Fe can more effectively trigger the participation of lattice oxygen in CoFe oxyhydroxides reconstructed from B, Fe─CoP nanofibers compared to incorporating only B or Fe. Therefore, the optimized B, Fe─CoP nanofibers exhibit superb OER activity with low overpotentials of 361 and 376 mV at 1000 mA cm−2 in alkaline freshwater and alkaline natural seawater, respectively. The present work provides significant guidelines and innovative design concepts for the development of OER electrocatalysts following the LOM pathway.

Intercalated and Surface-Adsorbed Phosphate Anions in NiFe Layered Double-Hydroxide Catalysts Synergistically Enhancing Oxygen Evolution Reaction Activity.

The oxygen evolution reaction (OER), a crucial semireaction in water electrolysis and rechargeable metal-air batteries, is vital for carbon neutrality. Hindered by a slow proton-coupled electron transfer, an efficient catalyst activating the formation of an O-H bond is essential. Here, we proposed a straightforward one-step hydrothermal procedure for fabricating PO43--modified NiFe layered double-hydroxide (NiFe LDH) catalysts and investigated the role of PO43- anions in enhancing OER. Phosphate amounts can efficiently regulate LDH morphology, crystallinity, composition, and electronic configuration. The optimized sample showed a low overpotential of 267 mV at 10 mA cm-2. Density functional theory calculations revealed that intercalated and surface-adsorbed PO43- anions in NiFe LDH reduced the Gibbs free energy in the rate-determining step of *OOH formation, balancing oxygen-containing intermediate adsorption/dissociation and promoting the OER. Intercalated phosphate ions accelerated precatalyst dehydrogenation kinetics, leading to a rapid reconstruction into active NiFe oxyhydroxide species. Surface-adsorbed PO43- interacted favorably with adsorbed *OOH on the active Ni sites, stabilizing *OOH. Overall, the synergistic effects of intercalated and surface-adsorbed PO43- anions significantly contributed to enhanced OER activity. Achieving optimal catalytic activity requires a delicate equilibrium between thermodynamic and kinetic factors by meticulously regulating the quantity of introduced PO43- ions. This endeavor will facilitate a deeper comprehension of the influence of anions in electrocatalysis for OER.

Carbon aerogel supported Ni–Fe catalysts for superior oxygen evolution reaction activity

Electrochemical water splitting presents an optimal approach for generating hydrogen (H2), a highly promising alternative energy source. Nevertheless, the slow kinetics of the electrochemical oxygen evolution reaction (OER) and the exorbitant cost, limited availability, and susceptibility to oxidation of noble metal-based electrocatalysts have compelled scientists to investigate cost-effective and efficient electrocatalysts. Bimetallic nanostructured materials have been demonstrated to exhibit improved catalytic performances for the oxygen evolution reaction (OER). Herein, we report carbon aerogel (CA) decorated with different molar ratios of Fe and Ni with enhanced OER activity. Microwave irradiation was involved as a novel strategy during the synthesis process. Inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM), Energy dispersive X-ray spectroscopy (EDAX spectra and EDAX mapping), Transmission Electron Microscope (TEM), High-Resolution Transmission Electron Microscope (HR-TEM), and Selected Area Electron Diffraction (SAED) were used for physical characterizations of as-prepared material. Electrochemical potential towards OER was examined through cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS). The FeNi/CA with optimized molar ratios exhibits low overpotential 377 mV at 10 mAcm−2, smaller Tafel slope (94.5 mV dec−1), and high turnover frequency (1.09 s−1 at 300 mV). Other electrocatalytic parameters were also calculated and compared with previously reported OER catalysts. Additionally, chronoamperometric studies confirmed excellent electrochemical stability, as the OER activity shows minimal change even after a stability test lasting 3600 s. Moreover, the bimetallic (Fe and Ni) carbon aerogel exhibits faster catalytic kinetics and higher conductivity than the monometallic (Fe), which was observed through EIS investigation. This research opens up possibilities for utilizing bi- or multi-metallic anchored carbon aerogel with high conductivities and exceptional electrocatalytic performances in electrochemical energy conversion.

Unraveling volcano trend in OER of metal–organic frameworks with asymmetric configuration through energy band engineering

Local symmetry breaking of catalysts has emerged as an effective strategy for finely tuning oxygen evolution reaction (OER) activity, yet the fundamental comprehension regarding asymmetric structure-activity relationships remains limited. Here, we propose the energy band engineering to bridge the correlation between established asymmetric electronic structure and adsorption/desorption ability of reaction intermediates within metal-organic frameworks (MOFs). The deliberate synthesis of CoM-MOFs (M=Cu, Ni, and Fe) with distinct coordination microenvironments enables the customization of asymmetric Co-O-M electronic structure. A volcano-shaped relationship can be revealed between calculated OER overpotential and average d‐band center (Ed) energy level for both active Co sites and substituted M. The CoFe-MOF, located close to the summit, showcases the balanced reaction intermediate behavior and thus for enhanced OER activity. This work presents a promising approach to thoroughly understand asymmetric electronic structure-activity relationships from the perspective of energy band engineering and further guide the discovery of high-efficiency MOF-based OER catalysts.

Tracking activity behavior of oxygen evolution reaction on perovskite oxides in alkaline solution via 3-dimensional electrochemical impedance spectroscopy

Developing electrocatalysts for the oxygen evolution reaction (OER) is essential for enhancing the efficiency of electrochemical water electrolysis. Among potential candidates, certain metal oxides, such as Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF), undergo structural transformations at their surface during OER operation, and the in situ-formed active layer enhances their OER activities. However, it is challenging to quantitatively evaluate the time-variant electrochemically active surface area (ECSA) and inherent catalytic activity per surface area (area-specific activity) of the oxides. In this study, we utilize the 3-dimentional electrochemical impedance spectroscopy (3D EIS) technique to reveal the variations in the ECSA and area-specific activity of the perovskite oxides during OER operation in an alkaline solution. In BSCF, the diameter of instantaneous Nyquist plots decreases as the number of potential cycling in the OER potential range increases, contrasting with other perovskite oxides, such as La0.5Sr0.5Co0.8Fe0.2O3−δ and LaCoO3. The fitting results of the Nyquist plots demonstrate that in BSCF, the ECSA significantly increases while the area-specific activity drops to less than half of its initial value during OER operation. Consequently, enhanced OER activity of BSCF mainly attributed to the increased ECSA rather than area-specific activity. This study demonstrates the utility of 3D EIS for tracking the ECSA and the area-specific activity of electrocatalysts.

Controllable synthesis of a hybrid mesoporous sheets-like Fe0.5NiS2@ P, N-doped carbon electrocatalyst for alkaline oxygen evolution reaction

Owing to the high cost of precious metal catalysts for the oxygen evolution reaction (OER), the production of highly efficient and affordable electrocatalysts is important for generating pollution-free and renewable energy via electrochemical processes. A facile hydrothermal approach was employed to synthesize hybrid mesoporous iron-nickel bimetallic sulfides @ P, N-doped carbon for the OER. The prepared Fe0.5NiS2@C exhibited an overpotential (η) of 250 mV at 10 mA/cm2. This exceeded the overpotentials recently reported for surface-modified P, N-doped carbon-based catalysts for the OER in a 1 M KOH medium. Moreover, the Fe0.5NiS2@C catalyst showed a notable Tafel slope of 90.5 mV/dec with long-dated stability even after 24 h at 10 mA/cm2. The superior OER performance of the Fe0.5NiS2@C catalysts may be due to their large surface area, sheet-like morphology with abundant active sites, fast transfer of mass and electrons, control of the electronic structure by co-treatment with heteroatoms (e.g., P and N), and the synergistic effect of bimetallic sulfides, making them favorable catalysts for the oxygen evolution reaction. Density functional theory (DFT) calculations showed that the Fe0.5NiS2@C catalyst exhibited strong H2O-adsorption energy. The enhanced OER activity of Fe0.5NiS2@C was attributed to its higher surface area, favorable H2O adsorption energy, improved electron transfer efficiency, and lower Gibbs free energy compared to those of the other proposed catalysts.

The formation of unsaturated IrOx in SrIrO3 by cobalt-doping for acidic oxygen evolution reaction

Electrocatalytic water splitting is a promising route for sustainable hydrogen production. However, the high overpotential of the anodic oxygen evolution reaction poses significant challenge. SrIrO3-based perovskite-type catalysts have shown great potential for acidic oxygen evolution reaction, but the origins of their high activity are still unclear. Herein, we develop a Co-doped SrIrO3 system to enhance oxygen evolution reaction activity and elucidate the origin of catalytic activity. In situ experiments reveal Co activates surface lattice oxygen, rapidly exposing IrOx active sites, while bulk Co doping optimizes the adsorbate binding energy of IrOx. The Co-doped SrIrO3 demonstrates high oxygen evolution reaction electrocatalytic activity, markedly surpassing the commercial IrO2 catalysts in both conventional electrolyzer and proton exchange membrane water electrolyzer.

Adjacent‐Confined Pyrolysis for High‐Density Phase Boundaries in Mo2C Nanosheets to Boost Oxygen Evolution

AbstractHeterostructure or doping engineering on Mo2C by coupling with transition metal nanoparticles/atoms can optimize catalytic activities for oxygen evolution reaction (OER). However, the intrinsic catalytic activity of Mo2C is not fully stimulated at the atomic level, which is challenging. Herein, an adjacent‐confined pyrolysis strategy to manipulate the intrinsic electronic structure of Mo2C directly is reported. During the nucleation and growth of Mo2C, the replacement of Mo atoms by adjacent Ni atoms induces the generation of high‐density phase boundaries (PBs) with alternating face‐centered cubic (fcc) and hexagonal close‐packed (hcp) hetero‐phase. The lattice deformity in PBs affords an ultrahigh density of active sites, endowing Mo2C nanosheets with excellent OER activity and superior stability. Theoretical calculations reveal that introduced Ni atoms activate the adjacent Mo sites and optimize the thermodynamic reaction energetics for enhanced OER activity. The work offers a general adjacent‐confined pyrolysis strategy to achieve PBs‐controlling in Mo2C nanosheets for catalytic application and beyond.

Lattice contraction-driven design of highly efficient and stable O–NiFe layered double hydroxide electrocatalysts for water oxidation

The slow progress of the oxygen evolution reaction (OER) is a key challenge in advancing water splitting as a viable technology for sustainable hydrogen production. Utilizing a self-standing NiFe layered double hydroxide (LDH) is a promising approach to address the slow kinetics of OER. Herein, the oxidized Fe2+-containing NiFe-LDH supported on Ni foam (O–NiFe-LDH@NF) is developed through corrosion engineering and aging. The growth mechanism is studied by adjusting urea content, hydrothermal temperature and time. It is revealed that the transformation of Fe2+ to Fe3+ in Fe2+-containing NiFe-LDH and the increase of Fe content leads to lattice contraction. Furthermore, detailed experiments and theoretical simulations illustrate that the substantial Fe content and lattice shrinkage promote the generation of Ni in high oxidation state and enhance the adsorption affinity toward the reaction species. Consequently, O–NiFe-LDH@NF exhibits enhanced OER activity and stability, with an exceptionally low overpotential of 197 mV and 354 mV observed at the current densities of 10 and 500 mA cm−2, respectively, and remarkable stability over 300 h. This approach can be generalized for designing advanced electrocatalysts.

Regulating Excess Electrons in Reducible Metal Oxides for Enhanced Oxygen Evolution Reaction Activity: A Mini-Review.

Identifying a universal activity descriptor for metal oxides, akin to the d-band center for transition metals, remains a significant challenge in catalyst design, largely due to the intricate electronic structures of metal oxides. This review highlights a major advancement in formulating the number of excess electrons (NEE) as an activity descriptor for oxygen evolution reaction (OER) on reducible metal oxide surfaces. We elaborate on the quantitative relationship between NEE and the adsorption properties of OER intermediates, and unveil the decisive role of the octet rule on the OER performance of these oxides. This insight provides a robust theoretical basis for designing effective OER catalysts. Moreover, we discuss critical experimental evidence supporting this theory and summarize recent advances in employing NEE as a guiding principle for developing highly efficient OER catalysts experimentally.

Nitrogen-Rich Conjugated Microporous Polymers with Improved Cobalt(II) Density for Highly Efficient Electrocatalytic Oxygen Evolution.

Developing efficient oxygen evolution catalysts (OECs) made from earth-abundant elements is extremely important since the oxygen evolution reaction (OER) with sluggish kinetics hinders the development of many energy-related electrochemical devices. Herein, an efficient strategy is developed to prepare conjugated microporous polymers (CMPs) with abundant and uniform coordination sites by coupling the N-rich organic monomer 2,4,6-tris(5-bromopyrimidin-2-yl)-1,3,5-triazine (TBPT) with Co(II) porphyrin. The resulting CMP-Py(Co) is further metallized with Co2+ ions to obtain CMP-Py(Co)@Co. Structural characterization results reveal that CMP-Py(Co)@Co has higher Co2+ content (12.20 wt %) and affinity toward water compared with CMP-Py(Co). Moreover, CMP-Py(Co)@Co exhibits an excellent OER activity with a low overpotential of 285 mV vs RHE at 10 mA cm-2 and a Tafel slope of 80.1 mV dec-1, which are significantly lower than those of CMP-Py(Co) (335 mV vs RHE and 96.8 mV dec-1). More interestingly, CMP-Py(Co)@Co outperforms most reported porous organic polymer-based OECs and the benchmark RuO2 catalyst (320 mV vs RHE and 87.6 mV dec-1). Additionally, Co2+-free CMP-Py(2H) has negligible OER activity. Thereby, the enhanced OER activity of CMP-Py(Co)@Co is attributed to the incorporation of Co2+ ions leading to rich active sites and enlarged electrochemical surface areas. Density functional theory (DFT) calculations reveal that Co2+-TBPT sites have higher activity than Co2+-porphyrin sites for the OER. These results indicate that the introduction of rich active metal sites in stable and conductive CMPs could provide novel guidance for designing efficient OECs.

Correlating Structural Disorder in Metal (Oxy)hydroxides and Catalytic Activity in Electrocatalytic Oxygen Evolution

AbstractUnderstanding the correlation between the structural evolution of electrocatalysts and their catalytic activity is both essential and challenging. In this study, we investigate this correlation in the context of the oxygen evolution reaction (OER) by examining the influence of structural disorder during and after dynamic structural evolution on the OER activity of Fe−Ni (oxy)hydroxide catalysts using operando X‐ray absorption spectroscopy, alongside other experiments and theoretical calculations. The Debye–Waller factors obtained from extended X‐ray absorption fine structure analyses reflect the degree of structural disorder and exhibit a robust correlation with the intrinsic OER activities of the electrocatalysts. The enhanced OER activity of in situ‐generated metal (oxy)hydroxides derived from different pre‐catalysts is linked to increased structural disorder, offering a promising approach for designing efficient OER electrocatalysts. This strategy may inspire similar investigations in related electrocatalytic energy‐conversion systems.

Correlating Structural Disorder in Metal (Oxy)hydroxides and Catalytic Activity in Electrocatalytic Oxygen Evolution.

Understanding the correlation between the structural evolution of electrocatalysts and their catalytic activity is both essential and challenging. In this study, we investigate this correlation in the context of the oxygen evolution reaction (OER) by examining the influence of structural disorder during and after dynamic structural evolution on the OER activity of Fe-Ni (oxy)hydroxide catalysts using operando X-ray absorption spectroscopy, alongside other experiments and theoretical calculations. The Debye-Waller factors obtained from extended X-ray absorption fine structure analyses reflect the degree of structural disorder and exhibit a robust correlation with the intrinsic OER activities of the electrocatalysts. The enhanced OER activity of in situ-generated metal (oxy)hydroxides derived from different pre-catalysts is linked to increased structural disorder, offering a promising approach for designing efficient OER electrocatalysts. This strategy may inspire similar investigations in related electrocatalytic energy-conversion systems.

Origin of Spin‐State Precise Modulation for Enhanced Oxygen Evolution Activity: Effect of Secondary Coordination Sphere

AbstractThe process of oxygen evolution reaction (OER) is crucial for energy storage and conversion, and the spin electronic structure of catalyst significantly influences its catalytic activity. Precisely regulating the spin electronic structures of metal active centers with intermediate spin (IS) states is challenging but important. This study presents a general method for achieving spin‐state precise modulation by altering the secondary coordination sphere (SCS) in Fe‐substituted LaCo1‐xFexO3 perovskites, denoted as Co6‐y−[Co]−Fey (y = 0–6). The concentration‐dependent SCSs can precisely regulate the spin state of Co3+ from high‐spin (HS) to IS and low‐spin (LS) state by tuning the Co─O binding energy of primary coordination sphere (PCS) to ≈567 KJ mol−1. The binding energy demonstrates a strong negative correlation with the spin state of Co3+, serving as a quantitative descriptor for precise spin‐state modulation. Furthermore, a universal optimal doping concentration is proposed for generating IS‐state Co3+ with the best OER activity, ranging from 1/(m+1) to 2/(m+1) in M‐doped ACo1‐xMxOy system with the coordination number of m. As a proof‐of‐concept, the LaCo7/9Fe2/9O3 with IS Co3+ exhibits significantly enhanced OER activity, almost six times higher than the control samples (without IS Co3+). These findings provide new insights into spin‐state modulation for effective OER catalysts.

Low-Temperature controlled synthesis of nanocast mixed metal oxide spinels for enhanced OER activity

The controlled cation substitution is an effective strategy for optimizing the density of states and enhancing the electrocatalytic activity of transition metal oxide catalysts for water splitting. However, achieving tailored mesoporosity while maintaining elemental homogeneity and phase purity remains a significant challenge, especially when aiming for complex multi-metal oxides. In this study, we utilized a one-step impregnation nanocasting method for synthesizing mesoporous Mn-, Fe-, and Ni-substituted cobalt spinel oxide (Mn0.1Fe0.1Ni0.3Co2.5O4, MFNCO) and demonstrate the benefits of low-temperature calcination within a semi-sealed container at 150–200 °C. The comprehensive discussion of calcination temperature effects on porosity, particle size, surface chemistry and catalytic performance for the alkaline oxygen evolution reaction (OER) highlights the importance of humidity, which was modulated by a pre-drying step. The catalyst calcined at 170 °C exhibited the lowest overpotential (335 mV at 10 mA cm−2), highest current density (433 mA cm−2 at 1.7 V vs. RHE, reversible hydrogen electrode) and further displayed excellent stability over 22 h (at 10 mA cm−2). Furthermore, we successfully adapted this method to utilize cheap, commercially available silica gel as a hard template, yielding comparable OER performance. Our results represent a significant progress in the cost-efficient large-scale preparation of complex multi-metal oxides for catalytic applications.

Enhanced oxygen evolution reaction activity on two-dimensional vdW ferromagnetic Cr2Ge2Te6 through synergism between two active sites.

To design an efficient, low-cost, and easily recoverable oxygen evolution reaction (OER) electrocatalyst, this work focuses on two-dimensional vdW ferromagnetic Cr2Ge2Te6. Based on the density functional theory (DFT) calculations, the adsorption of oxygen-containing intermediates during the OER process will gradually decrease the bandgap of Cr2Ge2Te6, thus increasing its electrical conductivity. More importantly, we propose a two active sites synergistic mechanism through a hydroxyl-boosted pathway. With the combined action of the two active sites, the binding between the oxygen-containing intermediates and the surfaces is enhanced. The enhancement comes from dramatic charge-transfer-induced Te-3p and O-2p orbital enhancement. As a result, the overpotential of the OER reduces from 1.25 to 0.59 V. We hope these findings will pave the way for more experimental and theoretical research to explore the potential applications of two-dimensional vdW ferromagnetic materials in energy storage and conversion.

Constructing vacancy-rich metal phosphates by the spatial effect of ionic oligomers for enhanced OER activity

By rationally selecting ionic oligomers as building blocks, sub-nano-sized gaps can be constructed in the solid structure of catalysts. This can overcome the inherent limitations associated with vacancy formation of the traditional nucleation pathway.