Synergistic Effect Of Doping Research Articles

Improvement of LiFePO4 electrochemical performance by organic zinc source doping in combination with crystalline carbon layer capping

In this paper, LiFePO4 cathode materials are prepared by hydrothermal method and co-modified using the synergistic effect of doping and capping. We investigate the effects of Zn[Formula: see text] doping and DPHP capping layer on the crystalline, microstructure, and electrochemical properties of LFP cathode materials, and the results indicate that the discharge capacity of the co-modified cathode material with 5% Zn[Formula: see text] doped and 7% DPHP capping layer is 162.1 mAh ⋅ g[Formula: see text], and the rate of capacity retention is still as high as 98.5% after 200 times of discharging and charging.

Construction of La1−xSrxNiO3/g-C3N4 type-Z heterojunctions with enhanced visible-light photocatalytic degradation of organic pollutants

Lanthanum nickelate (LaNiO3), known for its high visible-light absorption, is a promising photocatalyst for water purification. However, the low conduction band position and high photogenerated carrier complexation rate of pure LaNiO3 limit its photocatalytic activity. To address this issue, we investigated the synergistic effects of doping and constructing heterojunctions. A La0.9Sr0.1NiO3 (20%)/g-C3N4 (L2CN8) heterojunction was successfully created. In addition, various characterisation techniques were then employed to analyse the structure–performance relationships of these heterojunction photocatalysts in degrading organic dyes. Results revealed that at a 10% Sr doping level, the oxygen vacancy content was 0.68, which is significantly higher than that of LaNiO3 (0.05). The increased number of oxygen vacancies enhanced the electron capture ability and improved the separation efficiency of photogenerated carriers. Furthermore, the optimised L2CN8 (20 mg) achieved 81.2% and 73.8% removal of methylene blue (50.0 mL, 10 mg L−1) and tetracycline (50.0 mL, 10 mg L−1) under simulated visible-light irradiation (λ > 420 nm). Furthermore, an active species capture experiment confirmed the significant role of superoxide radicals (·O2−) in the degradation process. Based on these experimental findings, we proposed a rational Z-type charge transfer mechanism. This study holds great importance for water pollution control and environmental protection.

Synergistic Effects of Doping and Strain in Bismuth Catalysts for CO2 Electroreduction.

Doping is a recognized method for enhancing catalytic performance. The introduction of strains is a common consequence of doping, although it is often overlooked. Differentiating the impact of doping and strain on catalytic performance poses a significant challenge. In this study, Cu-doped Bi catalysts with substantial tensile strain are synthesized. The synergistic effects of doping and strain in bismuth result in a remarkable CO2RR performance. Under optimized conditions, Cu1/6-Bi demonstrates exceptional formate Faradaic efficiency (>95%) and maintains over 90% across a wide potential window of 900 mV. Furthermore, it delivers an industrial-relevant partial current density of -317 mA cm-2 at -1.2 VRHE in a flow cell, while maintaining its selectivity. Additionally, it exhibits exceptional long-term stability, surpassing 120 h at -200 mA cm-2. Through experimental and theoretical mechanistic investigations, it has been determined that the introduction of tensile strain facilitates the adsorption of *CO2, thereby enhancing the reaction kinetics. Moreover, the presence of Cu dopants and tensile strain further diminishes the energy barrier for the formation of *OCHO intermediate. This study not only offers valuable insights for the development of effective catalysts for CO2RR through doping, but also establishes correlations between doping, lattice strains, and catalytic properties of bismuth catalysts.

Design of S-scheme Sm-ZnO/N-rGO heterosystem for efficient H2 evolution under visible light illumination

Increasing the separation and transfer of photo-triggered electron-hole pairs is critical for developing a photocatalyst with excellent efficiency for hydrogen evolution reaction. Herein, an efficient and stable S-scheme Sm-ZnO/N-rGO heterosystem is successfully synthesized via a hydrothermal process for increased photocatalytic H2 activity. The anchoring of Sm-doped ZnO nanoparticles onto N-doped rGO nanosheets effectively enhances the light absorption, surface area, and transport and separation of photo-triggered carriers with strong redox potentials owing to the combined impact of doping and heterosystem formation. Upon light illumination, the photocatalytic hydrogen evolution performance over Sm-ZnO/N-rGO reaches 2361.8 μmolh-1g-1, which was significantly higher than that of Sm-ZnO and ZnO/N-rGO catalysts by a factor 5.5 and 2.9, respectively. In addition, the optimized composite shows high stability after five repetitive cycles. This research provides a feasible route to use the synergistic effect of doping and heterojunction for designing outstanding photocatalysts and further verifies the potentiality of ZnO for photocatalysis.

Synergistic effects of defects and surface engineering in Ni-Co metal oxides to improve the high performance of Zn-ion hybrid supercapacitors

NiCo2O4 (NCO) is an auspicious pseudocapacitor material for high energy density zinc-ion hybrid supercapacitors (ZHSCs), but its low intrinsic conductivity and significant volume expansion seriously hinder its electrochemical performance. Here, we develop a nitrogen (N) doped and oxygen-vacancy-rich (Ov) NiCo oxide nanolines grown in-situ on the carbon cloth (CC) named N-Ov-NCO@CC. The morphology and structure of N-Ov-NCO@CC were characterized by XRD, XPS, EPR, SEM and TEM. It can be clearly observed that N-Ov-NCO@CC nanowires are composed of many tiny nanoparticles, and this unique structure provides abundant gaps at the microscopic scale, providing ample sites for the attachment of electrolyte ions. Due to N-functionalization, synergistic effects of doping, defect and surface engineering are realized. As a result, N-Ov-NCO@CC exhibits significantly enhanced electrochemical performance. The N-Ov-NCO@CC single electrode exhibits a high capacitance of 993.0 F/g (496.5C/g) at 1 A/g and excellent cycle stability with a capacitance retention rate of 98 % after 5000 cycles. In addition, the assembled N-Ov-NCO@CC//Zn-ZHSC operates stably in the voltage range of 1.2–2.0 V. A high specific capacitance of 484.4 F/g is available at current densities of 1 A/g. In addition, it still has a high cycle life with a capacitance retention rate of 97.1 % after 10,000 cycles and a high specific energy/power (50.3 Wh/kg at 300.2 W/kg). Density function theory (DFT) verification shows that N-Ov-NCO has higher conductivity than Ov-NCO and pristine NCO, which is conducive to improving electrochemical performance. This work provides a new idea for developing stable electrode materials for new ZHSCs.

Carbon materials co-doped with nitrogen and sulfur for highly efficient catalytic activity in oxygen reduction and evolution

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) represent crucial steps in the functioning of fuel cells and metal-air batteries. Designing bifunctional oxygen electrode catalysts with high activity for both ORR and OER remains an immense challenge. In this study, we address this challenge by employing in-situ polymerization to design nitrogen and sulfur co-doped carbon materials (NSCs). The resulting NSC-1000–3 exhibits an onset potential of 1.03 V vs. RHE and a half-wave potential (E1/2) of approximately 0.89 V during ORR in an alkaline solution. When compared to commercial Pt/C, it demonstrates a positive shift of 60 mV in the half-wave potential. Furthermore, NSC-1000–3 displays outstanding oxygen evolution performance. At a current density of 10 mA cm−2, its performance matches that of RuO2. This material demonstrates exceptional performance in both ORR and OER, showcasing the synergistic doping effects of nitrogen and sulfur.

Tailoring of visible light driven photocatalytic activities of Bi2MoO6 flower-like microspheres via synergistic effect of doping and surface Plasmon resonance

Series of Er3+/Yb3+-codoped Bi2MoO6 (Bi2MoO6:Er3+/xYb3+) and Bi2MoO6:Er3+/0.03Yb3+@Biy flower-like microspheres were designed to improve the visible light driven photocatalytic activities of Bi2MoO6 flower-like microspheres. The electronic structure of Bi2MoO6 host was analyzed through the first-principle density functional theory. Excited at 980 nm, glaring UC emissions are gained in Bi2MoO6:Er3+/xYb3+ compound and their strongest intensities are obtained at × = 0.05, where the corresponding mechanism is a two-photon absorption process. Through studying the tetracycline (TC) degradation under visible light irradiation, the photocatalytic activities of final products were explored. Compared with Bi2MoO6 flower-like microspheres, these samples doped with Er3+ and Yb3+ can remove TC more efficiently and the optimal performance is achieved when a = 0.03. Furthermore, via using the surface plasmon resonance (SPR) effect caused by metallic Bi, the photocatalytic activities of the designed samples were further manipulated, where the TC removal rate of Bi2MoO6:Er3+/0.03Yb3+@Bi0.10 flower-like microspheres is 91.0% after irradiating by visible light for 24 min. Moreover, the included photocatalytic processes are triggered by ·O2–, ·OH and h+ active species. Additionally, the TC solution treated by the designed photocatalysts shows non-toxicity to plants. These results imply that Bi2MoO6:Er3+/0.03Yb3+@Biy flower-like microspheres are potential visible light driven photocatalysts for wastewater purification and our finding may also provide guidelines for tailoring of the photocatalytic activities of semiconductors by synergistic effect of doping and SPR engineering.

Surface-Modification of Doping and Coating Li1.2Ni0.2Co0.08Mn0.52O2 as a Long Life Cathode Material of Lithium-Ion Battery by Sodium Salt Treatment

Lithium-rich layered oxides are considered to be the most promising next-generation lithium-ion cathode materials due to their high specific capacity and energy density. However, its commercialization is limited due to its poor cycling stability and severe voltage decay. A NaH2PO4 molten salt treatment is designed, which simultaneously realizes Na+ doping and phosphate coating to improve the defects of lithium-rich materials. Sodium dihydrogen phosphate is of good contact with lithium-rich materials in the process of high temperature melting to facilitate surface sodium doping which is conducive to stabilizing the surface structure through lithium-sodium exchange. At the same time, the phosphate coating produced by lithium-sodium exchange and dehydration on the outer surface of the material can effectively inhibit the corrosion of the electrolyte. The modified material obtained by the synergistic effect of doping and coating has a capacity of 262.4 mAh·g−1 at 0.1 C and 169.6 mAh·g−1 at 5 C, the capacity retention rate of 73.6% after 500 cycles, and the voltage decay is significantly improved. A simple and effective method for improving the electrochemical performance of Li-rich layered materials is provided.

Dual active sites over TiO2 homojunction through tungsten doping and oxygen vacancies for enhanced photoelectrochemical properties

The introduction of dual active sites is a feasible strategy to enhance the photoelectrochemical (PEC) water splitting, but rational design based on structural construction and chemical composition is still a challenge. Herein, a homojunction composed of tungsten (W) doped titanium dioxide (TiO2) nanorods and oxygen vacancies modified TiO2 nanosheets is prepared via solid-state diffusion-hydrothermal method to improve the PEC activities. The TiO2 homojunction with dual active sites shows a 136 times enhancement in photocurrent density over the pristine TiO2 nanorods. PEC investigation reveals that the element W doped into the lattice of TiO2 causes the downshift of conduction band, and the formed defects state acting as the trapping sites could reduce photoinduced electron-hole pairs recombination rates. Moreover, the addition of polyvinylpyrrolidone leads to the generation of oxygen vacancies within TiO2 nanosheets, which facilitates the carrier transfer, and meanwhile suppresses the charge recombination. In addition, the type-II homojunction within the hierarchical nanostructure could not only advance the separation of photogenerated electron-hole pairs, but also provide more exposed active sites due to the enhanced specific surface area. The synergistic effect of doping, oxygen vacancies and homojunctions endows the considerably improved PEC performance.

A Novel Ni-doped ZnMn2O4/Mn2O3 nanocomposite synthesized by pulsed potential as superior zinc ion battery cathode material

The research and development of suitable cathode materials for Zn2+ storage is crucial to meet the large-scale energy storage application of zinc-ion batteries (ZIBs). However, manganese-based oxide cathodes, the most-studied category of cathode materials, suffer from capacity decline and weak electrical conductivity. Herein, Ni-doped ZnMn2O4/Mn2O3 nanocomposite has been synthesized using pulsed potential electrodeposition technique and then applied as cathode material for ZIBs. The Ni2+ doping effectively boosts the electrical conductivity and electrochemical performance of electrodes. Furthermore, simultaneous production of ZnMn2O4 /Mn2O3 nanocomposite as a two-phase compound and incorporation of Ni2+ in crystal structure leads to an improvement in reversibility and cyclability of Ni-doped ZnMn2O4/Mn2O3 nanocomposite. Moreover, the Ni-doped ZnMn2O4/Mn2O3 nanocomposite presents a specific capacity of 235.10 mAh g−1 (0.2 A g−1), higher than Undoped nanocomposite (215 mAh g−1). Besides, the Ni-doped ZnMn2O4/Mn2O3 nanocomposite shows superior electrochemical performance, with a reversible capacity of 114.67 mAh g−1 and capacity retention of 91.32%, obtained after 3000 cycles at 2 A g−1, while the Undoped -ZnMn2O4/Mn2O3 nanocomposite possesses the capacity of 61.85 mAh g−1 with 64.54% capacity retention at the same condition. The obtained results suggest that the synergistic effect of doping and two-phase compound synthesis provide new features for the practical application of ZIBs.

Dramatical improvement in temperature stability of ZnO modified PNN-PZT ceramics via synergistic effect of doping and composite

In this work, doping and composite are simultaneously utilized to improve the Tm of 0.55 Pb(Ni1/3Nb2/3)O3-0.135PbZrO3-0.315PbTiO3 ceramic by adding ZnO (PNN-PZT:xZnO). It is found that Zn ions prefer to substitute for Ni ions, making Ni ions spontaneously crystallize at grain boundaries in the form of an oxide. Moreover, limited by the solid solubility, superfluous ZnO particles also stay at grain boundaries with the increasing ZnO content. Thus, triple contribution of ions substitution, local stress fields and electric fields coexist in the PNN-PZT:xZnO ceramics with high ZnO content, dramatically improving the Tm from 102 °C to 171 °C. The excellent comprehensive electromechanical performance is obtained in the sample with x = 0.05: d33 ∼ 824 pC/N, d33* ∼1059 p.m./V, Tm ∼140 °C, Ec ∼5.2 kV/cm, Qm ∼87. As the ceramic is heated to 125 °C, its k33 and d33 values still remain ∼67% and ∼80% of the corresponding room temperature values as evidenced by in-situ temperature stability measurement. Our results indicate that PNN-PZT:xZnO ceramics are the most promising candidates to develop high-performance medical ultrasound transducers for imaging, meanwhile, provide a fresh design strategy to optimize the performance of the piezoelectric ceramics.

Cu-Doped ZnIn2S4/NixP Composites with Enhanced Carrier Dynamics and Photocatalytic Hydrogen Production Performance

Photocatalytic technology still faces enormous challenges to design and synthesize highly efficient photocatalytic materials with a high electron/hole separation efficiency, rapid charge migration, low carrier recombination rate, and strong visible light-harvesting capability. Herein, Cu-doped ZnIn2S4/NixP (marked CuyZIS/NP) composites were successfully synthesized by a simple two-step method. The synergistic effect of Cu2+ doping and the NixP cocatalyst on hydrogen evolution performance was investigated in detail. The results showed that superior photoactivity over CuyZIS/NP composites was achieved. The optimal Cu0.5ZIS/NP-1/2 sample had a hydrogen evolution rate of 4746.3 μmol·g–1·h–1 under visible light irradiation, which was approximately 15.98 times higher than that of pure ZnIn2S4 (297 μmol·g–1·h–1). This work may offer a valuable insight into understanding the synergistic effect of doping and cocatalysis and provide a guideline for designing and developing highly efficient visible light-driven photocatalysts toward a water splitting system.

Improved visible light triggered photocatalytic activities of BiOCl photocatalysts via a synergistic effect of doping and heterojunction engineering.

To manipulate the photocatalytic activities of BiOCl photocatalysts, doping and heterojunction engineering are simultaneously adopted. Herein, the photocatalysts Sm3+-doped BiOCl and BiOCl:Sm3+@yg-C3N4 were designed, in which their phase structure, morphology, optical properties and photocatalytic activities were systematically discussed. Excited at 408 nm, red emissions are seen from Sm3+-doped BiOCl microplates and their intensities were impacted by doping content, reaching the maximum value when the Sm3+ content was 1 mol% and the involved concentration mechanism was dominated by quadrupole-quadrupole interaction. Through analyzing the degradation of TC, the visible light triggered photocatalytic behaviors of the resultant compounds were studied. Compared with BiOCl microplates, an improved TC removal ability was seen in Sm3+-doped BiOCl microplates and the products with a Sm3+ content of 0.5 mol% show the best performance. Moreover, through constructing the heterojunction with g-C3N4, the TC removal capacity was further enhanced and the BiOCl:Sm3+@60%g-C3N4 exhibits the optimal photocatalytic activity, which was also much better than that of the commercial SnO2 and TiO2. Accordingly, the ˙O2-, h+ and ˙OH active species were proven to contribute to the involved visible light driven photocatalytic mechanism. Furthermore, the separation and recombination of photogenerated carries via the Z-scheme transfer process in the designed heterojunction composites, led to splendid photocatalytic properties. Additionally, it was verified that the TC solution treated with synthesized compounds was nontoxic toward plant growth. Our findings may propose an available route to regulate the photocatalytic performance of the visible light driven photocatalysts.

Corrigendum to “Synergistic effect of doping and surface engineering on LiNi0.5Mn1.5O4 and its application as a high-performance cathode material for Li-ion batteries” [Ceram. Int. 48(19 Part A) (2022) 27859–27869

Corrigendum to “Synergistic effect of doping and surface engineering on LiNi0.5Mn1.5O4 and its application as a high-performance cathode material for Li-ion batteries” [Ceram. Int. 48(19 Part A) (2022) 27859–27869

Synergistic effects of doping, composite formation, and nanotechnology to enhance the photocatalytic activities of semiconductive materials

Graphene, the promising carbon allotrope, has recently gained substantial research attention due to its unique physiochemical properties and distinctive 2D structure. Graphene-based composites have remarkable electronic and crystal properties and have emerged as promising photocatalysts owing to their greater surface area, superior adsorption, and charge transfer capacity. In this study, we made indium-doped molybdenum trioxide (In–MoO3) nanobelts. We combined them with nanosheets of reduced graphene oxide (rGO) to create a new photocatalyst for removing organic compounds (textile colors) from industrial waste. The prepared materials' surface morphology, crystalline structure, functional group detection, light absorption capacity, and electrochemical behavior have been investigated and validated using well-established characterization techniques. We examined the photocatalytic activity of freshly produced catalysts under the same circumstances by mineralizing the MB dye. The rGO/In–MoO3 composite outperformed pure MoO3 and In–MoO3 samples in photo-mineralization activity. After being exposed to light for one hundred minutes, the rGO/In–MoO3, In–MoO3, and MoO3 photocatalysts removed approximately 96%, 64%, and 49% of the MB dye, respectively. According to the reaction kinetics, the rGO-supported In–MoO3 sample removed the dye at a rate of 0.0250/min. This rate was 2.43 and 4.03 times higher than the rate that was attained by the samples that consisted just of bare MoO3 and In–MoO3, respectively. In chronoamperometric analysis, the rGO/In–MoO3 catalyst showed a 4.68 and 1.65-fold higher transient photocurrent response than the MoO3 and In–MoO3 catalysts, respectively. The synergistic properties of the significantly conducting graphene matrix and nanoscaled In–MoO3 were primarily responsible for the rGO/In–MoO3's improved photomineralization performance. These effects increased the separation of e−-h+ and improved the light-harvesting capacity. This new research shows a practical way to make highly effective photocatalysts that can be used in wastewater treatment in industry.

Solvent stimuli-responsive off-on fluorescence induced by synergistic effect of doping and phase transformation for Te4+ doped indium halide perovskite: Giving printable and colorless ink for information encryption and decryption

Since traditional fluorescent materials are too easily observed by the eyes just under the UV light, off-on fluorescent materials are explored as the new generation of fluorescent labels. In the “off” state, such off-on fluorescent labels cannot be observed by naked eyes under either natural light or UV light. Only after a specific decryption treatment to make the fluorescent materials turning into the “on” state, the fluorescent labels can be observed under the UV light. Up to now, it is still a challenge to prepare fluorescent inks with aforementioned ideal properties by using halide perovskite materials. Herein, we reported the first example of Te4+ doped indium halide perovskite inks with both off-on fluorescence under solvent stimuli and invisible ink color by the naked eyes. The synergistic effect of doping/undoping of Te4+ together with the reversible phase transformation between Cs2InCl5(H2O) and Cs3InCl6 under solvent stimuli is key for the off-on fluorescence of crystals. Under acid solvent, the substitutional doping of Te4+ during the process of phase transformation from Cs3InCl6 to Cs2InCl5(H2O):Te4+ gives rise to “turning-on” orange emission from Te-induced self-trap emission (STE). Under the stimuli of methanol, the dissolution of Te4+ from the crystals destroys the structure of Te4+ in ligand-field and results in “turning-off” Te-induced emission during the process of phase transformation from Cs2InCl5(H2O):Te4+ to Cs3InCl6. On the basis of the Te4+ doped indium halide perovskite, printable and colorless ink can be prepared for the confidential information encryption and decryption. Since the mixture of Cs3InCl6 crystals and TeCl4 have no absorption in visible light scope, the printed encrypted information by such off-state fluorescent ink is colorless and invisible by the naked eyes under either ambient light or UV light. After decryption by acid solvent stimuli, the resulted Cs2InCl5(H2O):Te4+ doping crystals have a large Stokes shift with absorption below 450 nm from the excitation of Te4+ in ligand-field and emission around 570 nm from Te-induced STE. It makes the decryption information still colorless and invisible by the naked eyes under the ambient light but visible and readable under the UV light. In comparison to traditional undoped CsPbBr3/CsPb2Br5 perovskites with small Stokes shift and eye-visible ink color, the current colorless Te4+doped indium halide perovskites are no doubt providing better security level for both encrypted and decrypted information.

Synergistic effect of doping and nanotechnology to fabricate highly efficient photocatalyst for environmental remediation

Nanotechnology and metal-doping are two promising techniques to make semiconductive material-based photocatalysts with higher surface area and modulating electronic structure. Using the simple surfactant-assisted co-precipitation approach; we synthesized nanostructured Zn-doped CuO (Zn0.4Co 0.6 O) as a visible-light-driven catalyst for environmental remediation. The morphology, texture, crystal structure, phase, charge transport properties, and chemical constitution of the as-prepared materials were characterized through advanced physiochemical characterization. Using the Rhodamine B (RhB) dye and the bacteria Escherichia coli (E-coli), the photocatalytic and antibacterial activities of CuO and Zn-doped CuO were investigated and compared to evaluate the effect of the doping technique. Surfactant-assisted synthesized Zn-doped CuO samples demonstrated excellent photocatalytic practicability against Rhodamine B dye, with a mineralization efficiency of up to 92.89% within 70 min and a high pseudo-first-order kinetic constant (K) of 0.033 min-1. The photocurrent response of the Zn-doped CuO sample was about double that of the CuO sample, demonstrating that the nanoarchitecture and modified electronic structure of the Zn-doped CuO sample resulted in increased photocatalytic activity. Furthermore, the Zn-doped CuO photocatalyst demonstrated enhanced antibacterial activity, killing E. coli bacteria by creating reactive oxygen species (ROS) that disrupt their important cellular processes and functions. Thus, our proposed Zn-doped CuO photocatalytic with faster degradation kinetics, good recyclability, and a lower electron-hole recombination probability could be used for environmental remediation. • Nanostructured Zn-doped CuO was prepared by using the surfactant co-precipitation approach. • Physicochemical and electrical properties of the Zn-doped and pristine CuO samples were investigated. • Zn-doped CuO mineralized 92.89% RhB dye in 70 min under visible light irradiation. • The kinetics, photoelectrochemical properties and reusability tests were also performed. • The Zn-doped CuO catalyst also showed excellent potential against E-coli .

High-performance anion exchange membrane water electrolyzer enabled by highly active oxygen evolution reaction electrocatalysts: Synergistic effect of doping and heterostructure

Anion exchange membrane water electrolyzers (AEM electrolyzers) have been demonstrated for efficient green hydrogen production. The primary advantage of AEM electrolyzers is replacing the noble metal catalysts with low-cost platinum group metal (PGM)-free catalysts. Despite some astonishing demonstrations of high-performance AEM electrolyzers [1–4], most of them suffer from lower energy efficiency due to the poor catalytic activity of PGM-free catalysts. Herein, to improve the performance of AEM electrolyzers, we developed a CeO2/CoFeCe-layered double hydroxide (LDH) heterostructure as the OER catalyst. The Ce doping modulates the electronic structures of CoFe-LDH while creating a CeO2/CoFeCe LDH interface, which dramatically improves the OER activity. The Ce doping synergizes with the CeO2/CoFeCe LDH interface to enable a high-performance AEM electrolyzer, achieving an exceptional current density of 2.7 A/cm2 at 1.8 Vcell. This work validates that AEM electrolyzers equipped with PGM-free OER catalysts can achieve comparable energy efficiency with proton exchange membrane water electrolyzers (PEM electrolyzers).

Synergistic effect of doping and surface engineering on LiNi0.5Mn1.5O4 and its application as a high-performance cathode material for Li-ion batteries

In this study, we synthesize V5+-doped LiNi0.5Mn1.5O4 (LNMO) and subject it to SiO2 surface modification using a coprecipitation method. The synergistic effect of ion doping and interfacial engineering improves the electrochemical properties of LNMO by accelerating its redox kinetics and prolonging its cycling life. The experimental results and density functional theory simulation data indicate that V5+-ion doping caused the Fermi level of LNMO to shift toward the conduction band, thereby narrowing the bandgap of LNMO because of the n-type doping effect. However, the introduction of V5+ ions prevents Li + -ion migration in LNMO, which hinders the ion intercalation–deintercalation process of LNMO cathodes. Therefore, the V5+-doped LNMO compound with optimal V5+-ion doping concentration was expected to present the highest rate capability. In addition, SiO2 surface modification provides a protective layer that inhibits metal dissolutions and significantly improves cathode cycling stability. Owing to the synergistic effect of doping and interfacial modification, the fabricated LNMO cathode presented remarkable energy storage capacity with discharge capacities of 133/118.8 mAh/g at 0.2/10 C and a capacity retention of 87.9% after 200 cycles at 4 C.

Doping and Vacancy Engineering in a Sandwich‐like g‐C3N4/NiCo2O4 Heterostructure for Robust Oxygen Evolution

AbstractHerein, N doping and O vacancy were simultaneously introduced into a g‐C3N4/NiCo2O4 heterostructure by a simple reflux and calcination strategy. The constructed g‐C3N4 displayed a porous lamellar structure with N‐doped carbon. Furthermore, numerous ultrathin NiCo2O4 nanosheets with abundant O vacancies tend to grow vertically on the porous g‐C3N4 lamellar, forming a sandwich‐like heterostructure. The prepared sandwich‐like g‐C3N4/NiCo2O4 heterostructure exhibited excellent oxygen evolution reduction (OER) activity with a low overpotential of 294 mV at 10 mA cm−2. Meanwhile, the heterostructure presented superior long‐term stability, retaining a current density of 97.9% after a 50 h chronoamperometry test. The outstanding OER performance is ascribed to the synergistic effect of doping and vacancy engineering in the catalyst, the strong coupling interaction between g‐C3N4 and NiCo2O4, and the porous sandwich‐like structure with abundant active sites. Therefore, the synthetic strategy of g‐C3N4/NiCo2O4 heterostructure can be extended to fabricate high‐performance noble metal‐free electrocatalysts for water splitting.