NiFe-LDH Nanosheets Research Articles

Construction of core-shell NiFe LDH/Co(OH)F amorphous/crystalline heterostructure for synergistically enhanced electrocatalytic water oxidation

The development of high performance non-precious transition metal electrocatalysts for the oxygen evolution reaction (OER) is essential for the practical application of electrocatalytic water splitting. A promising strategy to prepare highly efficient and stable electrocatalysts for the OER can be achieved by constructing heterointerfaces between the amorphous and crystalline phases. Herein, a novel three-dimensional (3D) core-shell structured NiFe-LDH/Co(OH)F electrocatalyst on nickel foam (NF) with an amorphous/crystalline interface was achieved by growing 2D amorphous NiFe LDH nanosheets onto 1D crystalline Co(OH)F nanorod arrays using a simple two-step hydrothermal method. The resulting NiFe LDH/Co(OH)F/NF electrode exhibits outstanding electrochemical OER performance with an overpotential of 202 and 260mV at the current density of 10 and 100mAcm-2, a Tafel slope of 44.06mV dec-1, and an ultra-high stability over 100h at 300mAcm-2 without obvious degradation in 1M KOH. This research affords a new way to construct high-performance 3D hierarchical non-noble metal electrocatalysts for OER.

Ce-doped NiFe-layered-double-hydroxide hierarchical nanocomposite and metal/imidazolate framework carbon nanotube nanocomposite: A bifunctional material for OER electrocatalyst and supercapacitor electrode applications

The development of nanocomposites as electrocatalysts with low cost and high efficiency for OER and as electrode material enhancing the electrochemical performance of supercapacitors are the most popular investigations in this field. Herein, a new bifunctional composite including Ce-doped NiFe-LDH Nanosheets and ZIF-derived carbon base incorporating neodymium and Fe into the structure of Zeolitic Imidazolate Framework is proposed and the construction was through entering Fe-ZIF8@Nd-ZIF67 into the structure of NiFeCe-LDH in different ratios of 10, 20 and 30 %. Various physical and electrochemical tests were conducted to evaluate the nanocomposites. Results indicated that the composite presented a hierarchical porous structure and exhibited outstanding performance for OER and supercapacitor applications. According to the results, the 30 % composite of NiFeCe-LDH/ Fe-ZIF8@Nd-ZIF67 exhibits a superior onset overpotential of 170 mV and an overpotential of 300 mV at a current density of 10 mA·cm−2. Besides, it shows an excellent specific capacitance of 345.36 (F.g−1) at 1 A.g−1. Hence, the synthesized nanocomposite demonstrated outstanding performance in both OER and supercapacitor applications.

NiMo/NiFe-LDH heterostructured electrocatalyst for hydrogen production from water electrolysis

Constructing low-cost and efficient catalysts for electrocatalytic water splitting to produce hydrogen is of great significance. In this study, we successfully prepared NiMo/NiFe-LDH electrocatalysts with abundant coupled interfaces using a hydrothermal method and electrodeposition. The synergistic effect between the NiMo alloy and NiFe-LDH nanosheets induces charge redistribution at the interface and accelerates charge transfer, thus improving reaction kinetics and enhancing electrocatalytic performance. Experimental results show that at a current density of 10 mA cm−2, the HER overpotential of NiMo/NiFe-LDH is 35 mV, demonstrating excellent water-splitting performance. This work provides insights into the development of alloy/transition metal hydroxides for efficient water-splitting hydrogen production.

Synergistic adsorption-photocatalytic remediation of methylene blue dye from textile industry wastewater over NiFe LDH supported on tyre-ash derived activated carbon

The photocatalytic performance of the multilayered NiFe LDH/Activated Carbon was evaluated for the degradation of methylene blue (MB) in industrial textile wastewater, considering prior adsorption on the photocatalyst surface. The XRD, XPS, BET, TEM and FE-SEM results confirmed that the highly exposed mesoporous layers, carbon backbone, and interlayer anions serve as active sites responsible for the adsorption of MB dye due to the expected electrostatic interactions. Electrochemical methods such as CV, LSV and EIS revealed the improved conductivity and supported the interactions observed. Encouraged by these interactions, the irradiation of visible light enabled the degradation of methylene blue, and the degradation products were monitored using UPLC chromatograms and MS spectra. The removal efficiencies of the MB dye were found to be 17.5 %, 51.2 %, 67.1 %, 84.8 %, and 94.2 % due to photolysis, adsorption, and degradation on AC, NiFe LDH nanosheets, and NiFe LDH/AC nanocomposite, respectively. The results of the UPLC chromatograms and MS spectra suggested that MB was mineralized into simpler fragments after 30 min of visible light irradiation. Scavenging studies were examined using a series of scavenging agents. However, the maximum photodegradation was attained in the absence of the scavengers. The reusability studies showed that the MB photodegradation efficiency declined by 20.8 %, possibly due to the loss of the catalyst during the washing step. Nonetheless, the NiFe LDH/AC structure remained intact, suggesting the strong stability of the photocatalyst. The plausible degradation mechanism and probable degradation pathway of MB were outlined and supported by the chromatographs and MS results. The overall results suggest that photocatalysis of cationic dyes such as MB on NiFe LDH/AC should be encouraged to work towards sustainable solutions for textile water treatment.

Advanced activation of peroxymonosulfate by NiFe-LDH/CeO2 heterostructure photocatalysts toward medical wastewater remediation

The great harm of antibiotic residues in medical wastewater to the ecological environment and human health has become the focus of social attention. Herein, we designed a new peroxymonosulfate (PMS) activation system by in-situ anchoring NiFe-LDH nanosheets into CeO2 (NFC) as a heterogeneous photocatalyst to degrade pollutants. The NFC/PMS/Vis system showed excellent and rapid degradation effect on tetracycline (TC) under the synergistic effect of photocatalysis and PMS activation, and the removal rate of TC was about 98.8 % within 40 min. The chemical compositions, microstructures, and optical properties of synthesized photocatalysts were studied by a series of characterization methods such as XRD, XPS, SEM, TEM and UV-DRS. The effects of various reaction systems and operating parameters such as initial concentration, catalyst dosage, and PMS concentration on the degradation efficiency of TC over optimized NFC-4 composite were investigated. The active species in the reaction system and the dominant SO4− were confirmed by quenching tests and electron paramagnetic resonance (EPR) measurements, and a plausible photocatalytic mechanism for PMS activation and pollutant remediation was further proposed.

A novel 3D hierarchical NiFe-LDH/graphitic porous carbon composite as multifunctional adsorbent for efficient removal of cationic/anionic dyes and heavy metal ions

Developing effective adsorbents for wastewater purification is crucial, as excessive emissions of toxic dyes and heavy metal ions have been proven harmful to ecosystems and human health. A NiFe-layered double hydroxide/graphitic porous carbon (NiFe-LDH/GPC) composite was fabricated by introducing NiFe-LDH nanosheets into GPC via a simple hydrothermal method to utilize the advantages of both materials fully, and thus ultimately obtain a composite adsorbent with improved adsorption properties. The samples obtained were comprehensively characterized by various characterization means, and the effects of several critical influential factors on the pollutant uptake capability of the NiFe-LDH/GPC were also studied through batch experiments. The results show that the as-synthesized NiFe-LDH/GPC exhibits a three-dimensional (3D) fluffy ultrathin-wall hierarchical porous structure, which possesses a high specific surface area and pore volume separately up to 506.74 m2/g and 0.22 cm3 g−1 as well as a relatively narrow pore size distribution. These characteristics bring advantages to enhance the adsorption ability of the NiFe-LDH/GPC for cationic/anionic dyes and heavy metal ions such as congo red (CR), malachite green (MG) and hexavalent chrome (Cr(VI), which reached the maximum adsorption capacity of 1726.51 mg/g, 1157.11 mg/g and 155.72 mg/g under the optimum conditions, respectively. Meanwhile, the adsorption behavior can be well described by the pseudo-second-order kinetic model and Langmuir isotherm model, reflecting that the sorption process mainly occurred chemically in the adsorbent monolayer. Furthermore, the NiFe-LDH/GPC maintained relatively high adsorption performance after multicycle testing, manifesting its good recyclability and stability.

Interlayer-spacing regulation of NiFe LDH nanosheets cathode with high rate performance for chloride ion battery

Chloride ion batteries (CIBs) possess the multiple advantages of high theoretical volumetric energy density, abundant precursor resources and high safety due to the dendrit-free characteristic, which provide more choices and opportunities for electrochemical energy storage. In this work, NiFe LDH nanosheets with different interlayer spacing are prepared using a simple co-precipitation method with the interlayer spacing of LDH nanosheets extended from 7.695 Å to 24.114 Å. Expanding interlayer space of LDHs nanoplates helps to the promote ion diffusion and enhance their action kinetics. Additionally, the increased oleophobicity between NiFe LDH nanosheets cathode with increased interlayer spacing and solvent PC is beneficial for the structural stability of the materials during cycling. Compared with typical chloride ion-intercalated NiFe LDH nanosheets, the NiFe-C17H25O3 LDH with the maximum interlayer spacing demonstrates a performance improvement of about 213 % (with a discharge specific capacity of 64.2 mAh/g after 200 cycles) at high current density and good rate performance. This work provides a simple and effective interlayer spacing control strategy for the design of CIBs cathodes under high current density.

Ultrasonic-assisted Fenton reaction inducing surface reconstruction endows nickel/iron-layered double hydroxide with efficient water and organics electrooxidation

Nickel/iron-layered double hydroxide (NiFe-LDH) tends to undergo an electrochemically induced surface reconstruction during the water oxidation in alkaline, which will consume excess electric energy to overcome the reconstruction thermodynamic barrier. In the present work, a novel ultrasonic wave-assisted Fenton reaction strategy is employed to synthesize the surface reconstructed NiFe-LDH nanosheets cultivated directly on Ni foam (NiFe-LDH/NF-W). Morphological and structural characterizations reveal that the low-spin states of Ni2+ (t2g6eg2) and Fe2+ (t2g4eg2) on the NiFe-LDH surface partially transform into high-spin states of Ni3+ (t2g6eg1) and Fe3+ (t2g3eg2) and formation of the highly active species of NiFeOOH. A lower surface reconstruction thermodynamic barrier advantages the electrochemical process and enables the NiFe-LDH/NF-W electrode to exhibit superior electrocatalytic water oxidation activity, which delivers 10 mA cm−2 merely needing an overpotential of 235 mV. Besides, surface reconstruction endows NiFe-LDH/NF-W with outstanding electrooxidation activities for organic molecules of methanol, ethanol, glycerol, ethylene glycol, glucose, and urea. Ultrasonic-assisted Fenton reaction inducing surface reconstruction strategy will further advance the utilization of NiFe-LDH catalyst in water and organics electrooxidation.

Tuning built-in potential of NiP/NiFe LDH p-n junction towards efficient electrocatalytic water and urea oxidation

Oxygen evolution reaction (OER) and urea oxidation reaction (UOR) are critical half-reactions to realize sustainable hydrogen production. However, the sluggish dynamics derived from the multi-electron pathways necessitate the exploration for efficient catalysts. Herein, a p-n junction nanorod array composed of Mo doped NiP nanorod and ultrathin NiFe LDH nanosheets (NiMoP/NiFe LDH) is proposed to regulate charge distribution of interface for triggering decomposition of water and urea. The p-n junction with a powerful built-in potential (EBI) of 1.2 V at the interface facilitates the adsorption and fracture of chemical group in water and urea molecules. Consequently, the heterostructured electrode demonstrates exceptional electrochemical performance with ultralow potentials of 1.43 and 1.33 V (vs. RHE) at 10 mA cm−2 for OER and UOR, respectively. The overall urea electrolysis driven by NiMoP/NiFe LDH needs only 1.51 V to deliver 100 mA cm−2. This work demonstrates a promising strategy to regulate the EBI of semiconductor heterostructure for energy conversion and sewage treatment.

Heterogenous Fe2P-NiFe layered double hydroxide nanostructures for boosting oxygen evolution reaction

One effective approach to improve the slow kinetics of oxygen evolution reaction (OER) for water splitting is to develop high-performance electrocatalysts. The Fe2P-NiFe LDH/NF catalyst with hetero-interfaces in this work was created using an easy two-step process that involved electrodeposition and hydrothermal processes. In the alkaline electrolyte, the as-prepared Fe2P-NiFe LDH/NF demonstrates improved OER performance. The Fe2P-NiFe LDH/NF catalyst only requires a low overpotential of 200 mV to achieve 10 mA cm−2, indicating the high efficiency for electrochemical reactions. Additionally, the Tafel slope of the catalyst is measured to be 59 mV dec−1. Even at a high current density of 100 mA cm−2, the overpotential of Fe2P-NiFe LDH/NF is only 250 mV, which is noticeably smaller than that of NiFe LDH/NF and commercial IrO2/NF. In addition, the current density of Fe2P-NiFe LDH/NF remains stable without any degradation during a 12 h durability test. By the SEM and TEM results, it showed that Fe2P with a crystalline-amorphous hybrid structure is grown at the edge of NiFe LDH nanosheets. The average length of Fe2P-NiFe LDH nanosheet is about 600 nm, which is longer than that of NiFe LDH nanosheets (about 400 nm). This increased size provides a larger specific area. As a result, more exposed active sites and a synergistic effect at the hetero-interface between Fe2P and NiFe LDH were achieved, which produces a distinct decrease in charge transfer resistance and promotes catalytic performance. Moreover, density functional theory (DFT) calculations emphasize the significance of rationally designed hetero-interfaces in increasing OER activity. It is found that the Fe2P-NiFe LDH/NF with a hetero-interface is an efficient OER catalyst for water splitting.

The decoration of NiFe layered-double-hydroxide/NiFe nanoalloy grown in a corrosion-cell by MoS2 nanosheets as a binder-free electrode for efficient overall water splitting

Nickel-Iron layered double hydroxides (NiFe-LDH) prepared by corrosion engineering has been proven effective for electrochemical overall water splitting, but the growth mechanism is still controversial. In this work, nano-Fe (0) powder was used as the iron substrate to produce NiFe nanoalloy under corrosion conditions as the corrosion-cell cathode, and then NiFe-LDH nanosheets were deposited. The NiFe-LDH/NiFe nanoalloy particles were captured on carbon cloth by a "network" structure by interlacing MoS2 layers, creating a binder-free self-supporting electrode (MoS2/NiFe-LDH/NF-NP/CC). The MoS2/NiFe-LDH/NF-NP/CC exhibited excellent overall water splitting performance, with a current density of 10 mA cm−2 at a voltage of only 1.52 V, owing to the abundant HER active sites at the edge of MoS2 nanosheets, the high conductivity and OER properties of the NiFe-LDH/NiFe nanoalloy, as well as the effective 3D heterojunction structure.

Production of H2 and Glucaric Acid Using Electrocatalyst Glucose Oxidation by the Ta NiFe LDH Electrode.

The slow anodic oxygen evolution reaction (OER) significantly limits electrocatalytic water splitting for hydrogen production. We proposed the electrocatalyst for glucose oxidation by Ta-doping NiFe LDH nanosheets to simultaneously obtain glucaric acid (GRA) and hydrogen gas as a useful byproduct. Superior glucose oxidation reaction (GOR) activity is demonstrated by the optimized Ta-NiFe LDH, which has a low overpotential of 192 mV, allowing for a small Tafel slope of 70 mV dec-1 and a current density of 50 mA cm-2. The Ta NiFe LDH-oxidized glucose to GRA with a 72.94% yield and 64.3% Faradaic efficiency at 1.45 VRHE. Herein, we report the Ta NiFe LDH/NF electrode for the GOR&hydrogen evolution reaction (HER), which exhibits a cell voltage of 1.62 V to reach a current density of 10 mA cm-2, which is 250 mV lower compared to OER&HER (1.87 V). This study reveals that GOR is an energy-efficient and cost-effective method for producing H2 and valorizing biomass.

Integrating Sulfur Doping with a Multi-Heterointerface Fe7S8/NiS@C Composite for Wideband Microwave Absorption.

Heterointerface engineering is presently considered a valuable strategy for enhancing the microwave absorption (MA) properties of materials via compositional modification and structural design. In this study, a sulfur-doped multi-interfacial composite (Fe7S8/NiS@C) coated with NiFe-layered double hydroxides (LDHs) is successfully prepared using a hydrothermal method and post-high-temperature vulcanization. When assembled into twisted surfaces, the NiFe-LDH nanosheets exhibit porous morphologies, improving impedance matching, and microwave scattering. Sulfur doping in composites generates heterointerfaces, numerous sulfur vacancies, and lattice defects, which facilitate the polarization process to enhance MA. Owing to the controllable heterointerface design, the unique porous structure induced multiple heterointerfaces, numerous vacancies, and defects, endowing the Fe7S8/NiS@C composite with an enhanced MA capability. In particular, the minimum reflection loss (RLmin) value reached -58.1dB at 15.8GHz at a thickness of 2.1mm, and a broad effective absorption bandwidth (EAB) value of 7.3GHz is achieved at 2.5mm. Therefore, the Fe7S8/NiS@C composite exhibits remarkable potential as a high-efficiency MA material owing to the synergistic effects of the polarization processes, multiple scatterings, porous structures, and impedance matching.

Short-time potentiostatic assisted borate to induce the generation of ultrathin NiFe LDH active phase for industrial-level water oxidation

Self-supported NiFe-based oxygen evolution reaction (OER) catalysts with high activity and durability are essential for the industrialization of green hydrogen. Herein, Boron-interfered NiFe LDH nanosheets (B2-NiFe-(a-10)) with abundant wrinkle structure are prepared by introducing nonmetallic sources into the surface reconstruction of layered double hydroxide (NiFe LDH) through a novel short-time potential constant activation strategy. It enhances interactions with the electrolyte, decreases Arrhenius activation energy (Ea), accelerates efficient charge transfer and O2 escape rate. The as-reconstructed B2-NiFe-(a-10) exhibits outstanding alkaline OER activity with an ultralow overpotential of 290 mV at 100 mA cm−2 and excellent durability (100 h). Additionally, density functional theory calculations further reveal that the interaction optimizes the adsorption of oxygenated intermediates (*OH→*O), induces the center of the d-band toward the Fermi energy level, and lowers the dissociation barrier of H2O. Moreover, the anion-exchange membrane water electrolyzer (AEMWE) achieves a current density of 1 A cm−2 at 1.97 V.

Excellent Photoelectro-Catalytic Performance of In2S3/NiFe-LDH Prepared by a Two-Step Method

In this work, we synthesize hierarchical In2S3/NiFe-layered double hydroxide (In2S3/NiFe-LDH) nanoarrays on an F-doped SnO2 glass substrate via a two-step method, which the In2S3 electrode film was firstly prepared using chemical bath deposition on F-doped SnO2 glass substrate, and then the layered NiFe-LDH was deposited on In2S3 electrode film by hydrothermal synthesis. The two-component photoanode In2S3/NiFe-LDH exhibits significantly enhanced photoelectrochemical properties compared with the In2S3 single-component; due to that, the NiFe-LDH nanosheets depositing on the surface of In2S3 nanocrystal can reduce the accumulation of photogenic holes, facilitate the separation of photogenerated charge carriers, and enhance the light response and absorption. After being decorated with the NiFe-LDH nanosheets, the In2S3/NiFe-LDH photoanode displays a lower onset potential of 0.06 V and an enhanced photocurrent density as high as 0.30 mA·cm−2 at the potential of 1.0 V (vs. RHE). Furthermore, it also displays a 90% degradation rate of xylose oxidizing into xylose acid in 3 h under UV light. This work provides a promising approach for designing new heterojunctions applied to biomass degradation.

An efficient solution based on the synergistic effects of nickel foam in NiFe-LDH nanosheets for oil/water separation

Efficient oil-water separation has always been a research hotspot in the field of environmental studies. Employing a one-step hydrothermal approach, NiFe-layered double hydroxides (LDH) nanosheets were synthesized on nickel foam substrates. The resulting NiFe-LDH/NF membrane exhibited rejection rates exceeding 99% across six diverse oil-water mixtures, concurrently demonstrating a remarkable ultra-high flux of 1.4 × 106 L·m−2·h−1. This flux value significantly surpasses those documented in existing literature, maintaining stable performance over 1000 manual filtration cycles. These breakthroughs stem from the synergistic interplay among the three-dimensional channels of the nickel foam, the nanosheets, and the hydration layer. By leveraging the pore size of the foam to enhance the functionality of the hydration layer, the conventional trade-off between permeability and selectivity was transformed into a balanced force relationship between the hydration layer and the oil phase. The operational and failure mechanisms of the hydration layer were examined using the prepared NiFe-LDH/NF membrane, validating the correlation between oil phase viscosity and density with hydration layer rupture. Additionally, an extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was employed to investigate changes in interaction energy, further reinforcing the study's findings. This research contributes novel insights and assistance to the comprehension and application of hydration layers in other membrane studies dedicated to oil-water separation.

In-situ growth of NiFe-LDH nanosheets on carbon nanofibers as polysulfide barriers for Li-S batteries

To solve the shuttle effect of polysulfides and sluggish reaction kinetics in Li-S batteries, a functional interlayer added between the cathode and separator has been proven to be a very effective means. The pleasing interlayer is usually formed by the conductive skeleton and active components that have polysulfide adsorption and catalytic conversion abilities. In this paper, an electrospinning method assisted with in-site growth strategy has been developed to design a hierarchical functional film with NiFe-LDH nanosheets anchored on carbon nanofibers (CNF@NiFe-LDH). Structural characterizations and electrochemical measurements have been taken to indicate that the CNF@NiFe-LDH interlayer can effectively restrict the diffusion of polysulfides and accelerate the redox kinetics.

CoO supported NiFe layered double hydroxide sandwich-like nanosheets on hierarchical carbon framework for efficient electrocatalytic oxygen evolution.

Exploration of greatly efficient and steady non-noble oxygen evolution reaction (OER) electrocatalysts is of great significance in improving the overall efficiency of energy density systems such as regenerative fuel cells, water electrolyzes, and metal-air batteries. Herein, inspired by hierarchical 3D porous structures with open microchannels of natural wood, CoO@NiFe LDH sandwich-like nanosheets were anchored on the carbonized wood (CW) via electrodeposition and calcination strategies. The strong interactions between CoO nanosheets and NiFe LDH nanosheets endow CoO@NiFe LDH/CW electrocatalyst with high catalytic properties toward the OER comparable to CoO/CW and NiFe LDH/CW. The optimized CoO@NiFe LDH/CW electrocatalyst demonstrates good OER catalytic performance with an overpotential of 230 mV at 100 mA cm-2. This work presents an innovative approach to utilize renewable resources for constructing advanced free-standing catalysts.

Exploring Ir-doped NiFe-LDH nanosheets via a pulsed laser for oxygen evolution kinetics: in situ Raman and DFT insights

Herein, we present Ir-doped NiFe-LDH nanosheets synthesized via a pulsed laser irradiation strategy, showing superior electrocatalytic OER kinetics. We investigate the origin of activity in NiFeIr-LDH through in situ/operando Raman and DFT studies.

Self-supported NiFe-LDH nanosheets on NiMo-based nanorods as high-performance bifunctional electrocatalysts for overall water splitting at industrial-level current densities

Self-supported NiFe-LDH nanosheets on NiMo-based nanorods as high-performance bifunctional electrocatalysts for overall water splitting at industrial-level current densities