Accelerated Charge Transfer Research Articles

Insights into the kinetics–morphology relationship of 1-, 2-, and 3D TiNb2O7 anodes for Li-ion storage

Understanding the influence of electrode material’s morphology on electrochemical behavior is of great significance for the development of rechargeable batteries, however, such studies are often limited by the inability to precisely control the morphology of electrode materials. Herein, nanostructured titanium niobium oxides (TiNb2O7) with three different morphologies (one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D)) were synthesized via a facile microwave-assisted solvothermal method. The influence of the morphological dimension of TiNb2O7 as electrode material on the electrochemical performance in Li-ion batteries (LIBs) and the underlying correlation with the electrochemical kinetics were studied in detail. 2D TiNb2O7 (TNO-2D) shows a superior rate capability and cycling stability, associated with improved kinetics for charge transfer and Li-ion diffusion, compared to the 1D and 3D materials. Operando X-ray diffraction measurements reveal the structural stability and crystallographic evolution of TNO-2D upon lithiation and delithiation and correlate the Li-ion diffusion kinetics with the lattice evolution during battery charge and discharge. Moreover, carbon-coated TNO-2D achieves enhanced rate capability (205 mAh·g−1 at 50 C) and long-term cycling stability (87% after 1000 cycles at 5 C). This work provides insights into the rational morphology design of electrode materials for accelerated charge transfer and enhanced fast-charging capability, pushing forward the development of electrode materials for high-power rechargeable batteries in future energy storage.

Regulating Photocatalytic CO2 Reduction Kinetics through Modification of Surface Coordination Sphere

AbstractSolar‐driven reduction of CO2 to value‐added products represents a sustainable strategy for mitigating the greenhouse effect and addressing the related green‐energy crisis. Herein, it is demonstrated that modifying the surface coordination sphere can significantly enhance the reaction kinetics and overall efficiency of CO2 reduction. More specifically, the decoration of isolated Mn atoms over the multi‐edged TiO2 nano‐pompons (Mn/TONP) upshifts the d‐band center that allows favorable CO2 adsorption. Ultrafast spectroscopy demonstrates the greatly accelerated charge transfer between photoexcited multi‐edged TONP and the newly implanted Mn reactive centers, supplying long‐lifetime electrons to reduce absorbed CO2 molecules. By integrating adsorption and activation functions into the newly decorated Mn sites, the developed photocatalyst demonstrate impressive capacity for CO2 reduction (80.51 mmol g−1 h−1). The surface modulation strategy at the atomic level not only opens new avenues for regulating the reaction kinetics toward photocatalytic CO2 reduction, but also paves the way for the rational design of highly efficient and selective photocatalysts for clean energy conversion.

Facile construction of ZnWO4/ZnO porous nanoplates on reduced graphene oxide for superior lithium storage

Zinc tungstate (ZnWO4) shows great promise as an anode material for lithium-ion batteries (LIBs) owing to its reversible multi-electron redox reactions and high theoretical capacity. Nevertheless, the low conductivity and big strain during cycling can lead to the inferior electrochemical properties of the ZnWO4 anode, hindering its practical application. Herein, we report a novel composite with ZnWO4/ZnO porous nanoplates in-situ constructed on reduced graphene oxide (rGO) by a metal–organic framework template strategy. The nanoplates with good porosity are composed of nanoparticles and nanorods, providing a short Li+-diffusion distance and plentiful Li+ storage active sites. The introduction of rGO can accelerate charge transfer and reinforce structural stability. As a result of these advantages, the ZnWO4/ZnO/rGO composite as LIBs anode delivers a high reversible capacity of 811 mAh g after 100 cycles at 200 mA g−1, excellent rate capability (437 mAh g at 5000 mA g−1), and good long cycling stability (485 mAh g after 500 cycles at 2000 mA g−1). Notably, the rate capability of the composite far precedes the previously reported ZnWO4-based anodes. This work provides an efficient approach for designing and fabricating advanced metal tungstate-based anodes for high-performance LIBs.

P vacancies at the crystalline-amorphous interface of NiFe(OH)x/NiPx/NF enhance the catalytic activity of the oxygen evolution reaction

Efficient electrocatalysts are crucial for overcoming the sluggish kinetics of the oxygen-evolution reaction (OER) and facilitating the advancement of energy storage technologies such as metal-air batteries and hydrogen production through water electrolysis. This study proposes a synergistic approach combining amorphization and interfacial engineering to improve OER performance by fabricating heterojunctions between crystalline NiFe(OH)x and amorphous NiPx. The formation of a strongly coupled crystalline-amorphous heterojunction enables optimization of the electronic structure at the catalytic site and accelerates charge transfer at the interface, thereby improving the reaction kinetics. Notably, we investigate the dynamic adsorption behavior of PO43− during the OER process by introducing Na3PO4 into the electrolyte, revealing that P vacancies serve as active sites in promoting OER activity. Lastly, electrochemical measurements demonstrate that NiFe(OH)x/NiPx/NF exhibits a low overpotential of 220 mV at 10 mA cm−2 and Tafel slope of 35 mV·dec−1, surpassing the performance of laboratory-prepared noble metal catalysts and most reported NiFe-based electrocatalysts.

Hollow spheres of Co-doped V2O3 enveloped in N-doped carbon as efficient anode for sodium-ion storage

Vanadium oxides are potential anode materials for sodium-ion batteries, however, their application is limited for their rate capability and cycle life. Herein, hollow spheres of Co-doped V2O3 enveloped in N-doped carbon (Co-V2O3@NC) are prepared through a hydrothermal step with the following sintering process. The hollow spherical structure supplies short distance and large area for fast ion transfer kinetics, which also provides voids to ease the volume expansion. The strong coupling between Co-V2O3 nanoparticles and carbon layer constitutes a solid structure that enhances the conductivity and keeps electrode integrity. Co-doping introduces plenty of active sites for surface capacitance behavior and accelerates charge transfer. On account of the benefits, Co-V2O3@NC exhibits excellent Na+ storage properties as anode, including high capacity of 338.5 mAh g−1 at 0.1 A g−1, stable cycling capability of 240 mAh g−1 after 1000 cycles at 1 A g−1, and excellent rate performance. This work describes the importance of constructing specific structured materials for advanced anodes.

Cerium oxide boosted CoFe-N codoped carbon nanotubes with abundant oxygen-vacancies toward efficient oxygen reduction and methanol oxidation reaction

In this study, we designed a novel strategy that utilizes N-doped carbon nanotubes as the chemical bond supporter to stabilize ultrafine CoFe alloy and introduces secondary CeO2 active sites into the hybrid, resulting in the formation of CeO2/CoFe-NCNTs heterostructures with exceptional bifunctional electrocatalytic capabilities. To be specific, solution dispersion and high-temperature calcination methods were employed to create the CoFe-NCNTs active sites through the introduction of ethylenediamine into the network interstitials of Co-EDTA and Fe-EDTA. The CeO2/CoFe-NCNTs hybrid not only promotes oxygen absorption and conversion of intermediates, but also accelerates charge transfer capability, thus enhancing oxygen reduction reaction (ORR) performance, while simultaneously inducing boosted the methanol oxidation reaction (MOR) activity. Moreover, the well-dispersed CoFe nanoparticles within the hybrid hold significant potential for establishing metal-nitrogen bonds with the N-doped carbon nanotube network, resulting in efficient catalytic behavior driven by synergistic effects with CeO2 nanoparticles, which contributes to reactant activation. As expected, the resultant CeO2/CoFe-NCNTs-2 exhibits remarkable electrocatalytic performance, with a current density of 281.40 mA cm−2 at a scan rate of 200 mV s−1 and a low Tafel slope (71.3 mV dec−1) for MOR, as well as achieving excellent half-wave potential and onset potential values of 0.834 and 0.90 V (vs. RHE) for ORR. Additionally, it exhibits durable cycle stability for both MOR and ORR, retaining 92.8% and 96.4% of its initial current density during the I-t test, respectively. This work establishes a highly efficient bifunctional earth-abundant electrocatalysts for both anode and cathode reactions in methanol fuel cells.

Promoting photothermal catalytic CO2 reduction of Cd2In2S5/Cd0.3Zn0.7S heterojunction with encapsulated hydrogen evolution active site by accelerating charge transfer kinetics

The photothermal catalysis CO2 reduction is considered as an attractive means to solve the greenhouse effect and energy crisis. However, due to the slow charge transfer kinetics on the surface of the catalyst and sparse adsorption active site, the CO2 adsorption rate is low and the carrier life is short. So, the catalytic performance is limited. Here, a core–shell similar structure catalyst for photothermal CO2 reduction was constructed by growing of Cd0.3Zn0.7S (CZS) nanospheres on the surface of sulfur defect rich Cd2In2S5 (CIS) ultra-thin nanosheets, and which was coordinated by the interfacial chemical bond and the interfacial internal electric field. The Cd-S chemical bond became a direct channel to accelerate the transfer of electrons from the conduction band of CZS to the conduction band of CIS, leading to higher surface charge localization of CIS/CZS, and encapsulating the active site of hydrogen evolution of CZS. The core–shell similar structure was favorable for the spatial separation of photogenerated charges. The production of *HCO3– and *COOH intermediates on the CIS/CZS surface has been proved to be crucial for CO2 adsorption and CO generation by in situ Fourier transform infrared spectroscopy. The charge transfer mechanism of Type Ⅱ between CIS and CZS was proved by density functional theory calculation and in situ X-ray photoelectron spectroscopy. The CO yield of the optimized CIS/CZS heterojunction was 64.3 μmol·h−1·g−1, which was about 31.3 times that of pure CZS. This study provided a new idea for accelerating charge transfer dynamics and inhibiting competition reaction to promote the conversion of solar energy to fuel.

Ni-Rh-based bimetallic conductive MOF as a high-performance electrocatalyst for the oxygen evolution reaction.

Metal-organic frameworks (MOFs) have recently been considered the promising catalysts due to their merits of abundant metal sites, versatile coordination groups, and tunable porous structure. However, low electronic conductivity of most MOFs obstructs their direct application in electrocatalysis. In this work, we fabricate an Ni-Rh bimetallic conductive MOF ([Ni2.85Rh0.15(HHTP)2]n/CC) grown in situ on carbon cloth. Abundant nanopores in the conductive MOFs expose additional catalytic active sites, and the advantageous 2D π-conjugated structure helps accelerate charge transfer. Owing to the introduction of Rh, [Ni2.85Rh0.15(HHTP)2]n/CC exhibited substantially improved oxygen evolution reaction (OER) activity and exhibited only an overpotential of 320mV to achieve the current density of 20mAcm-2. The remarkable OER performance confirmed by the electrochemical tests could be ascribed to the synergistic effect caused by the doped Rh together with Ni in [Ni2.85Rh0.15(HHTP)2]n/CC, thereby exhibiting outstanding electrocatalytic performance.

Decorated NiFeOOH on high entropy perovskite oxide by interface engineering for efficient oxygen evolution and overall water splitting

High entropy perovskite oxide (HEPO) has proved to be one of the most promising candidates in the exploration of non-precious oxygen evolution reaction (OER) catalysts. Herein, we report a chemical bath deposition method for decorating NiFeOOH on lanthanide-based high entropy perovskite oxide (La-HEO) to form a rational core–shell heterostructure through direct atomic-scale contact to further enhance the OER activity of HEPO. Compared with La-HEO and NiFeOOH, the resulting La-HEO@NiFeOOH showed excellent OER performance, requiring an overpotential of 262 mV (10 mA cm−2) and a Tafel slope of 38 mV dec−1, which owes much to the accelerated charge transfer and the optimized adsorption energy of reaction intermediates caused by synergistic effects. Meanwhile, the water splitting electrolyzer demanded a current density of 10 mA cm−2 at 1.574 V for La-HEO@NiFeOOH(1:3)||Pt/C, which is lower than that of La-HEO||Pt/C. This study illustrates the effectiveness of interface engineering to boost the OER performance of HEPO, and reveals the potential of La-HEO@NiFeOOH as a promising OER electrocatalyst.

Ru-doping modulated electronic structure of bimetallic phosphide toward efficient overall water splitting

Efficient water splitting electrocatalysts with low cost is essential for the development of sustainable hydrogen energy. Ni foam supported Ru-doped NiCoP nanowire arrays (Ru–NiCoP@NF) are synthesized via a hydrothermal reaction followed by low-temperature phosphorization. The as-obtained Ru–NiCoP@NF exhibits outstanding bifunctional catalytic activity, achieving 100 mA cm−2 at the overpotentials of 108 and 264 mV for HER and OER, respectively, with a tiny loading of Ru (≈61.8 μg cm−2). The electrolyzer assembled using Ru–NiCoP@NF as the bifunctional electrode requires 1.62 V (with no iR correction) for 50 mA cm−2, 50 mV lower than RuO2–Pt/C based electrolyzer. The enhancement of Ru–NiCoP@NF is ascribed to Ru dopants, which contribute to formation of 3D nanowire arrays with the advantages of exposing sufficient active sites, accelerating charge transfer and outstanding mechanical strength. More importantly, the Ru atoms in NiCoP successfully modulate the charge densities around Ni, Co and P through strong electronic interaction, thus elevating the sluggish Volmer step for HER and promoting the adsorption capacity of oxygen-containing intermediates for OER.

Efficient hybrid capacitive deionization with MnO2/g-C3N4 heterostructure: Enhancing Mn dz2 electron occupancy by interfacial electron bridge for fast charge transfer

While MnO2 has been identified as a potent agent in the desalination process, its efficacy is significantly impeded by its inherent poor electrical conductivity and substantial ion diffusion barriers. By orchestrating an interfacial electron bridge within the MnO2/g-C3N4 heterostructure, reinforced through Npz-Mndz2 orbital hybridization, we have managed to significantly boost both SAC and SAR in the HCDI process. The reinforced Npz-Mndz2 orbital hybridization triggers a substantial electron transition from g-C3N4 to MnO2, culminating in a high Mn dz2 electron occupancy. Further analysis reveals the formation of a MnN chemical bond at the MnO2/g-C3N4 interface, operating as an essential electron transfer bridge from g-C3N4 to MnO2. This process concurrently initiates a rise in the Mn dz2 orbital energy level, equipping the Mn dz2 electron with superior redox activity. With these enhancements, the manufactured MnO2/g-C3N4 exhibits exemplary performance, boasting an improved SAC of 68 mg g−1 and SAR of 3.6 mg g−1 min−1 with a decreased energy consumption of 0.7224 kWh kg−1 at 1.2 V. This innovative work offers an unconventional roadmap for activating electron redox activity and thereby accelerating charge transfer in transition metal oxides.

Nitrogen-doped carbon trapped MnMoO4 microrods toward high performance aqueous zinc-ion battery

Manganese oxides as a class of favorable cathode materials in zinc-ion batteries (ZIBs), have garnered considerable concerns for their low cost, eco-friendliness as well as high energy density. Nonetheless, the practical applications of manganese oxides have been immensely hindered by sluggish reaction kinetics and moderate cycling stability as a result of their poor electronic/ionic conductivity. In this regard, nitrogen-doped carbon-coated MnMoO4 (MnMoO4@NC) is firstly designed with enhanced electrochemical kinetics in this work. The nitrogen-doped carbon coating on MnMoO4 enhances electric conductivity, inhibits Mn and Mo dissolution, and provides a large surface area, thereby increasing the contact area between cathode and electrolyte and offering more Zn2+/ H+ storage sites. What’s more, the MnMoO4@NC heterostructure formed built-in electric field with accelerated charge transfer is also elucidated by the first-principle calculations, which is in favor of the fast insertion/extraction of Zn2+ and H+. As a result, the MnMoO4@NC-2 exhibits optimal circulation endurance with a reversible capacity of 242.1 mA h g−1 together with capacity retention of 147.8 % at 1 A g−1 after 380 cycles. This study provides a new pathway for building durable ZIBs.

Electrochemical activated molybdenum oxides based multiphase heterostructures with high hydrogen evolution activity in alkaline condition

Electrochemical activation is an effective method for synthesizing economically feasible heterogeneous hydrogen evolution reaction (HER) electrocatalysts. Herein, we first synthesized MoO2-Co2Mo3O8 precatalyst, which was electrochemically activated to produce K2Mo3O10 within the original phase to form the heterogeneous structure. The electrochemically activated samples demonstrate exceptional HER activity in alkaline medium, which exhibit a low overpotential of 31 mV at current density of 10 mA cm−2 (135 mV at 100 mA cm−2), as well as a small Tafel slope of 34 mV dec−1. This is due to the creation of multiphase heterostructures that prompt interfacial interactions and accelerate charge transfer. Simultaneously, the creation of additional active sites increases their intrinsic activities. The combined effects collectively enhance the HER performance. The application of this method in the preparation of HER catalysts is still relatively unexplored, thus rendering our work a pioneering contribution to the field.

Sr3Fe1.5Zn0.5O7-δ as Cathode for Protonic-Conducting Solid Oxide Fuel Cells with Enhanced Oxygen Reduction Reaction Activity

Common concerns about green energy have led to a wide focus on solid oxide fuel cells (SOFCs) for their environmental friendship and high efficiency. As the most popular electrode, perovskite materials feature the flexible structure and abundant oxygen sites, which correspondingly leads to diverse doping strategies and good electrochemical performance. However, the high operating temperature results in hot corrosion of both cells and encapsulating materials. Operating under various atmospheres, the generated impurities also cause a measure of irreversible degradation. Here, we first introduced Zn to Sr3Fe2O7-δ perovskite cathode in protonic ceramic fuel cells (PCFCs). Ruddlesden-Popper oxides Sr3Fe2-xZnxO7-δ (SFZx, x=0, 0.1, 0.5) were successfully synthesized and exhibited great performance under intermediate temperatures. The polarization resistance is 0.072 Ω·cm-2 which is 47% lower than that of the undoped Sr3Fe2O7-δ, and the maximum peak power density of the single-cell of NiO-BaZr0.1Ce0.7Y0.2O3- δ(BZCY)|BZCY|SFZ05 reaches 523.56 mW·cm-2 at 750℃, increased by 22%. The improvement is attributed to the formation of oxygen vacancies and the larger triple-phase boundary areas. Furthermore, the electrochemical impedance spectra (EIS) and distribution of relaxation time (DRT) results manifest that the rate-limiting steps are accelerated charge transfer and ionic migration processes. Finally, SFZ05 also presented better CO2 tolerance under an atmosphere of 5% CO2/air. These results display that SFZ05 is a promising candidate for a highly active and stable cathode for PCFCs.

Highly efficient Z-scheme Ag3PO4/PtNPs/g-C3N4 photocatalyst for degradation of organic pollutants in water

Organic pollutants in water cause serious waste of water resources. Therefore, it is important to design efficient photocatalysts to address the problem of waste water. Herein, solid Z-scheme heterojunction photocatalyst, Ag3PO4/PtNPs/g-C3N4, was prepared via in-situ deposition. Under xenon lamp (full wavelength) irradiation, the catalyst efficiently degraded solutions of rhodamine B and phenol within 9 min and 30 min, respectively. This shows better photodegradation performance (99.4% of Rh B, and 97.0% of phenol) than other catalysts and demonstrates that the synergistic effect of its three components results in improved photocatalytic activity. Furthermore, holes and superoxide radicals were identified as main active species during catalysis with Ag3PO4/PtNPs/g-C3N4 based on scavenging experiments of active species and electron spin resonance detection results. In proposed photocatalytic mechanism, PtNPs act as a bridge and accelerate charge transfer on ternary Ag3PO4/PtNPs/g-C3N4. This study provides ternary Z-scheme heterojunction photocatalyst construction for application in the treatment of organic pollutants.

Simultaneous phosphorization and sulfuration to Synergistically promote the supercapacitor performance of heterogeneous (CoxNi1-x)2P/CoxNi1-xS hydrangea-like microspheres

How to effectively improve supercapacitors performances through electrode materials design is still an urgent task. Herein, a facile precursor strategy combining solvothermal synthesis and upstream gas method is proposed to regulate the structure and composition of the supercapacitor electrode material through doping and compositing. The precursors, CoxNi1-x microspheres, are synthesized through a facile solvothermal reaction with nickel/cobalt acetate in methanol without addition of any surfactants or templates, achieving the integration of cobalt and nickel species into a single structure. A subsequent simultaneous phosphorization and sulfuration process through an upstream gas method makes the CoxNi1-x precursor microspheres transform to heterogeneous (CoxNi1-x)2P/CoxNi1-xS microspheres in one step. The resulted (CoxNi1-x)2P/CoxNi1-xS microspheres show great enhanced supercapacitor performances with a high specific capacitance (1561 F g−1 at 1 A g−1 current density) and excellent cycling stability (a 89.7% capacitance retention after 5000 cycles at 10 A g−1) due to synergistic effects resulted from the coexistence of multiple elements, as well as the unique interface and structure caused by in-situ two-phase compositing, which can accelerate charge transfer and increase available active sites. Our study proves that simultaneous phosphorization and sulfuration is an effective means to adjust the microstructure of the electrode materials and thus promote their electrochemical performances.

Facile Electrochemical Synthesis of Bifunctional Needle-like Co-P Nanoarray for Efficient Overall Water Splitting.

The development of low-cost and high-performance bifunctional electrocatalysts for overall water splitting is still challenging. Herein, we employed a facile electrodeposition method to prepare bifunctional cobalt phosphide for overall water splitting. The needle-like cobalt phosphide (Co-P-1) nanoarray is uniformly distributed on nickel foam. Co-P-1 exhibits excellent electrocatalytic activity for hydrogen evolution reaction (HER, 85 mV at 10 mA/cm2, 60 mV/dec) and oxygen evolution reaction (OER, 294 mV at 50 mA/cm2, 60 mV/dec). The cell-voltage of 1.60 V is found to achieve the current density of 10 mA/cm2 for overall water splitting in the two-electrode system, comparable to that of previously reported Pt/C/NF||RuO2/NF. The excellent electrocatalytic performance can be attributed to the needle-like structure with more active sites, accelerated charge transfer and evolved bubbles' release. This work can provide new approach to the development of a bifunctional electrocatalyst for overall water splitting.

Integration of Single-Atom Catalyst with Z-Scheme Heterojunction for Cascade Charge Transfer Enabling Highly Efficient Piezo-Photocatalysis.

Piezo-assisted photocatalysis (namely, piezo-photocatalysis), which utilizes mechanical energy to modulate spatial and energy distribution of photogenerated charge carriers, presents a promising strategy for molecule activation and reactive oxygen species (ROS) generation toward applications such as environmental remediation. However, similarly to photocatalysis, piezo-photocatalysis also suffers from inferior charge separation and utilization efficiency. Herein, a Z-scheme heterojunction composed of single Ag atoms-anchored polymeric carbon nitride (Ag-PCN) and SnO2- x is developed for efficient charge carrier transfer/separation both within the catalyst and between the catalyst and surface oxygen molecules (O2 ). As revealed by charge dynamics analysis and theoretical simulations, the synergy between the single Ag atoms and the Z-scheme heterojunction initiates a cascade electron transfer from SnO2- x to Ag-PCN and then to O2 adsorbed on Ag. With ultrasound irradiation, the polarization field generated within the piezoelectric hybrid further accelerates charge transfer and regulates the O2 activation pathway. As a result, the Ag-PCN/SnO2- x catalyst efficiently activates O2 into ·O2 - , ·OH, and H2 O2 under co-excitation of visible light and ultrasound, which are consequently utilized to trigger aerobic degradation of refractory antibiotic pollutants. This work provides a promising strategy to maneuver charge transfer dynamics for efficient piezo-photocatalysis by integrating single-atom catalysts (SACs) with Z-scheme heterojunction.

Urchin-like alkaline nickel–cobalt carbonate derived Ni3S4/Co3S4 nanoparticles anchored on rGO for lithium/sodium-ion batteries with enhanced capacity

Transition metal sulfides (TMS) have emerged as promising anode materials for lithium and sodium ion batteries due to their high theoretical capacity and low cost. However, the severe volume expansion during the conversion reaction causes rapid collapse inevitability when used as anode material. Herein, we pertinently fabricated nanoscale Ni3S4/Co3S4 with uniform particle size homogeneously dispersed between pleated graphene (Ni3S4/Co3S4@rGO) through facile hydrothermal assisted by cationic surfactants. The construction of 3D nanocomposites significantly shortens ion migration distances and enriches electronic pathways, accelerating charge transfer kinetics while maintaining good stability. Uniformly distributed bimetallic sulfides and rGO limit each other's aggregation, allowing the excellent structural properties of the material to be maintained over time. Thus, the Ni3S4-Co3S4@rGO electrodes deliver a high reversible capacity of 972.5 mAh/g upon 200 cycles at 100 mA g−1 in Lithium-ion battery and 487.5 mAh/g upon 150 cycles at 100 mA g−1 in Sodium-ion battery, as well as excellent rate capacity in both. These excellent properties show the potential for expansion of this simple synthetic method in the field of alkali metal batteries.

Ag improves the performance of the oxygen evolution reaction by lowering the D-band center of the active site Ni

The development of high activity catalysts with excellent durability is a great challenge to realize the industrialization of electrolytic water oxygen evolution. In this work, Ag nanoparticles modified cross column nickel-iron hydroxyl oxide system (NiFeAg) nanocomposites were synthesized by a two-step strategy. Through XPS spectrum, Tafel slope, and EIS electrochemical impedance spectroscopy, it was found that Ag mainly plays a conductive role, accelerates charge transfer, and adjusts the surface electronic structure, to improve the activity of the catalyst. Impressive is the overall hydrolysis performance, with a current density of 10 mA cm−2 achieved at an overpotential of 211 mV, which shows better performance than other catalysts reported in the literature. Finally, through the theoretical calculation of the determination steps of adsorption energy and rate of oxygen-containing intermediates, it is determined that the active center of the catalyst is mainly Ni site. According to the theory of D-band center, Ag can effectively adjust the D-band center, thereby adjusting the adsorption strength of Ni sites on the surface of NiFe catalyst to adsorbent, and finally improving the OER performance of the catalyst.