Layered Double Hydroxide Nanosheets Research Articles

NiAl LDH nanosheets based on Ag nanoparticles-decoration and alkali etching strategies for high performance supercapacitors

Layered double hydroxides (LDHs) represent a category of two-dimensional layered intercalation materials, showing significant potential as electrode materials for the production of high-energy-density supercapacitors due to their tunable composition, ease of synthetic modification, and low cost. Here, we constructed alkali-etched NiAl LDH-OH nanosheets/Ag nanoparticles (NPs) composite material (Ag@NiAl LDH-OH) for high-performance supercapacitors through a simple solvent-thermal reaction. The alkali treatment is employed to selectively etch some Al3+ ions, generating cation vacancies as active sites for energy storage. Additionally, under the simultaneous influence of strong alkalis and vacancies, the interlayer spacing of LDHs expands, aiding in the promotion of interlayer ion mobility. Meanwhile, the decoration of silver nanoparticles ensures excellent electron conductivity in the NiAl-LDH-OH nanosheets, thereby facilitating improved utilization of the active substance and achieving outstanding rate performance. The Ag@NiAl LDH-OH electrode, when prepared, demonstrates a significant increase in specific capacitance, reaching 1790 F g−1 at a current density of 1 A g−1. This represents approximately 7 times the specific capacitance of the pristine NiAl LDH electrode, with a capacity retention of 79 % even under a high current density of 20 A g−1. Moreover, the assembled asymmetric supercapacitor (ASC) attains a maximum energy density of 138.25 Wh kg−1 at a power density of 700 W kg−1, maintaining 81 % of its initial specific capacitance after 20000 cycles. This research introduces novel pathways for advancing high-energy-density SCs.

A high-flux atomically dispersed MIL-100 (Fe) incorporated PMS-based LDH catalytic membrane for the removal of micropollutants from secondary effluent wastewater

This study fabricated a CoFe layered double hydroxide (CoFeLDH) membrane incorporating the metal–organic framework (MOF) MIL(100)Fe, tailored for a peroxymonosulfate (PMS) based system. Among various combinations of MOF and LDH nanosheets on a PVDF substrate, the highest water flux, reaching 1900 L/m2/hr/bar, was achieved with an LDH/MOF ratio of 5:1 and an MOF concentration of 0.025 M. The optimized membrane exhibited exceptional performance, achieving 99 % degradation of ranitidine at 0.1 mM PMS. The LDH MOF catalytic membrane exhibited excellent treatment performance in real water matrices and demonstrated long-term operational efficiency. The effective removal of ranitidine by this catalytic membrane was attributed to a synergistic combination of radical (SO4− and OH) and non-radical (singlet 1O2 and electron transfer O2) oxidation pathways, with SO4− and singlet 1O2 playing a predominant role. Post-activation, 40 % of surface Co2+ and 65 % of Fe2+ in the LDH MOF membrane were found in the + III oxidation state, highlighting the significance of metal catalytic sites and the reusability potential of the membrane. The durability of the membrane was evident through 10 cycles, achieving a flux recovery ratio of 95 % in the first cycle and sustaining efficient performance across pH variations (3 to 9) and exposure to various anions. Importantly, negligible metal leaching was observed for the real water samples, ensuring suitability for large-scale applications.

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.

In-situ growth transformation and oxygen vacancy synergistic modulation of the electronic structure of NiCo-LDH enables high-performance hybrid supercapacitors

This article successfully constructs NiCo-LDH nano cages formed by in-situ triggering (IS-LDH), and synergistically modulates the electronic structure by introducing oxygen vacancies. The in-situ triggered generation of NiCo-LDH (IS-LDH) by synthesizing ZIF-67 owns a typical rhombic dodecahedral structure and sensitivity to acid etching. Characterization analysis revealed that the IS-LDH nanocage succeeded the polyhedral structure morphology of ZIF-67 but with multiple vertically aligned nanosheets on the shell. Oxygen vacancies (Ov) were introduced into the IS-LDH through a chemical reduction process using sodium borohydride. The findings demonstrate that the synthesized OvIS-LDH nanocapacitor has a low charge transfer resistance (Rct) with a specific capacitance as high as 1111C g−1 (at 1 A g−1). After 10,000 cycles of charge-discharge measurements, the capacity retention rate was 89.45%. Density functional theory (DFT) calculations confirmed that the inclusion of Ov enhanced the repulsion of OH− by the LDH nanosheets and improved the intrinsic conductivity of LDH. The assembled hybrid supercapacitor (OvIS-LDH//AC) successfully powered an LED light for 20 min. This study proposes a logical approach for developing anode materials that can enhance the performance of supercapacitors.

In Situ Tracking of Water Oxidation Generated Nanoscale Dynamics in Layered Double Hydroxides Nanosheets.

Layered double hydroxides (LDHs) are potential catalysts for water oxidation, and it is recognized that they undergo dynamic evolution during the operation. However, little is known about the interfacial behaviors at the nanoscale under working conditions nor the underlying effects on electrocatalytic performance. Herein, using electrochemical atomic force microscopy, we in situ visualize the heterogeneous evolution of LDH nanosheets during oxygen evolution reaction (OER). By further combining density functional theory calculations, we elucidate the origin of the heterogeneous dynamics and their impact on the OER efficiency. Our findings demonstrate that NiCo LDHs transform to the catalytically active NiCoOx(OH)2-x phase during OER, and the redox transition between is accompanied by compressive and tensile strain, leading to in-plane contraction and reversible expansion of the nanosheets. Nonisotropic strain and out-of-plane strain relaxation due to defects and interparticle interactions result in cracking and wrinkling in the nanostructure, which is responsible for the partial activation and long-term deterioration of LDH electrocatalysts toward the OER. With this knowledge, we suggest and validate that engineering defects can precisely tune these dynamic behaviors, improving the OER activity and stability among LDH-based electrocatalysts.

Shape Self-Adaptive Liquid Embolic Agent for Ultrafast and Durable Vascular Embolization.

Minimally invasive embolization greatly decreases the mortality resulting from vascular injuries while still suffering from a high risk of recanalization and systematic thrombosis due to the intrinsic hydrophobicity and poor adhesion of the clinically used liquid embolic agent of Lipiodol. In this study, a shape self-adaptive liquid embolic agent was developed by mixing biocompatible poly(acrylic acid) (PAA), two-dimensional magnesium-aluminum layered double hydroxide (LDH), and poly(ethylene glycol)200 (PEG200). Upon contact with blood, the injectable PAA-LDH@PEG200 would quickly absorb water to form an adhesive and mechanically strong PAA-LDH thin hydrogel within 5 s, which could firmly adhere to the blood vessel wall for ultrafast and durable embolization. In addition, benefiting from the "positively charged nucleic center effect" of LDH nanosheets, the liquid PAA-LDH@PEG200 could avoid vascular distension by PAA overexpansion and possess high shock-resistant mechanical strength from the blood flow. Furthermore, both in vitro and in vivo embolization experiments demonstrated the complete embolic capacity of liquid PAA-LDH@PEG200 without the occurrence of recanalization for 28 days and also the great potential to act as a platform to couple with chemotherapeutic drugs for the minimized transcatheter arterial chemoembolization (TACE) treatment of VX2 tumors without recurrence for 18 days. Thus, liquid PAA-LDH@PEG200 developed here possesses great potential to act as a shape self-adaptive liquid embolic agent for ultrafast and durable vascular embolization.

Unveiling hygroresponsive ion conduction performances of layered double hydroxide nanosheets

Layered double hydroxide (LDH) nanostructures have attracted significant attention as versatile two-dimensional building blocks with exceptional properties, including specific surface area, selective growth, variable anion exchange, catalytic reactivity, and intrinsic hydroxide ion conductivity. Due to the rare intrinsic hydroxide ion conduction arising from the abundant hydroxyl groups, LDHs have been applied in various fields, including supercapacitors, batteries, electrocatalysts, photocatalysts, and proton exchange membranes. However, the correlation between temperature, humidity, and structural properties of LDH as an ion conductive channel device has not yet been investigated. In this study, we verified the ion-conducting mechanism of LDH by utilizing closely packed two-dimensional scroll nanosheets with variations in temperature and humidity. The ion flux in the LDH nanosheets operates through surface-to-surface hopping influenced by water activity and the desorption/adsorption state of water. Moreover, the LDH nanosheets demonstrate an exceptional ability for self-recovery, absorbing moisture from the surrounding environment and diffusing it to internal structures. This water absorption property significantly contributes to the surface water-induced ion conduction observed in LDH nanosheets.

Synthesis of Zr2ON2 via a urea-glass route to modulate the bifunctional catalytic activity of NiFe layered double hydroxide in a rechargeable zinc-air battery

The development of a highly efficient, stable, and low-cost bifunctional catalyst is imperative for facilitating the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). However, significant challenges are involved in extending its applications to rechargeable zinc-air batteries. This study presents a bifunctional catalyst, Zr2ON2@NiFe layered double hydroxide (LDH), that was developed by utilizing a urea-glass route for synthesizing the Zr2ON2 precursor, followed by riveting NiFe LDH nanosheets using a hydrothermal method. Specifically, the vertical distribution of NiFe LDH on the Zr2ON2 surface ensures the maximization of the number of accessible active sites and interfacial catalysis of NiFe LDH. Notably, Zr2ON2@NiFe LDH demonstrates ORR and OER bifunctional electrocatalytic behavior and high stability owing to its heterostructure and composition. Furthermore, a rechargeable zinc-air battery using a Zr2ON2@NiFe LDH electrocatalyst as the air cathode demonstrated a high peak power density (172 mW cm−2) and galvanostatic charge-discharge cycle stability (5 mA cm−2 over 443 h). Thus, this study presents an efficient and cost-effective strategy for the design of bifunctional electrocatalysts.

Oxygen Vacancy Generation and Stabilization in Layered NiFeCo Double Hydroxide Nanosheets for a Highly Efficient Oxygen Evolution Reaction

Oxygen Vacancy Generation and Stabilization in Layered NiFeCo Double Hydroxide Nanosheets for a Highly Efficient Oxygen Evolution Reaction

Enhancing oxygen evolution reaction through self-reconstruction of 2D nanoarrays on nickel foam

The synthesis of nanostructured transition metal compounds with adjustable components are often challenging due to the involvement of multiple synthetic procedures or complex manipulations. In this work, a one-step self-regulating acid-etching strategy is employed for nickel iron-layered double hydroxide (NiFe LDH). A two-dimensional (2D) NiFe LDH nanosheet is speedy and efficiently formed. This as-prepared NiFe LDH exhibits electrocatalytic activity for oxygen evolution reaction (OER). This approach avoids numerous structural design challenges and provides highly active sites and a robust interface between catalyst and support. As a result, 2D NiFe LDH electrodes demonstrate highly efficient OER performance with a low overpotential of 300 mV and a Tafel slope of 70.6 mV dec−1 at a current density of 100 mA cm−2.

In situ semi-etching of bimetallic LDH nanosheet arrays into FeNi-LDH/MOF to boost oxygen evolution reaction

The inherent sluggish kinetics of water oxidation is the core issue for electrochemical hydrogen production from water splitting. Metal organic frameworks (MOFs) with tunable porous structures, abundant coordination metal centers and large specific surface area are expected as efficient electrocatalysts. In this paper, FeNi-LDH/MOF composite nanostructures were successfully constructed on carbon cloth (CC) through partially converting iron-nickel layered double hydroxide (FeNi-LDH) into FeNi-MOF (NiFe(CN)5NO) by an in-situ semi-etching method. The MOF nanocrystals in this material are in-situ decorated on the surface of FeNi-LDH nanosheets, providing abundant open active sites and mass transfer channels for electrocatalysis. Thanks to the synergistic effect of the LDH and MOF, as well as the exceptional hierarchical architecture, the FeNi-LDH/MOF/CC as a self-supported electrode exhibits distinguished electrocatalytic OER performance, with a low overpotential of 263 mV@100 mA cm−2 and a small Tafel slope of 50.2 mV dec-1 in 1.0 M KOH. In addition, the catalyst exhibits good durability with almost constant current density during 24 h OER test. This work provides an effective way to design high-performance MOFs-based composite electrocatalytic materials.

Three-dimensional Ni foam supported Pt/NiFe LDH catalyst with enhanced oxygen activation for room-temperature formaldehyde oxidation

Room-temperature catalytic oxidation of formaldehyde (HCHO) has been extensively investigated due to its high efficiency, convenience, and environmental friendliness. Herein, nickel-iron layered double hydroxide (NiFe LDH) nanosheets were synthesized in-situ on a nickel foil (NF) using a facile one-step hydrothermal method, followed by the deposition of ultra-low content (0.069 wt%) of Pt nanoparticles through NaBH4 reduction. The resulting three-dimensional (3D) hierarchical Pt/NiFe-NF catalyst exhibited exceptional activity for the complete decomposition of formaldehyde to carbon dioxide (CO2) at room temperature (∼95 % conversion within 1 h), as well as remarkable cycling stability. The 3D porous structure of Pt/NiFe-NF provides fast transport channels for the diffusion of gas molecules, making the active catalyst surfaces more accessible. Moreover, abundant hydroxyl groups in NiFe LDH serve as adsorption centers for HCHO molecules to form dioxymethylene (DOM) and formate intermediates. Furthermore, electronic interactions between NiFe LDH and Pt enhance the adsorption and activation of O2 on Pt surfaces, leading to the complete decomposition of intermediates into non-toxic products. This work presents new insights into the design and preparation of Pt-based 3D hierarchical catalysts with surface-rich hydroxyl groups for the efficient removal of indoor HCHO.

Enhancing the Performance of 2D Ni-Fe Layered Double Hydroxides by Cabbage-Inspired Carbon Conjunction for Oxygen Evolution Reactions.

Layered double hydroxide (LDH) nanosheets as one type of two-dimensional materials have garnered increasing attention in the field of oxygen evolution reaction (OER) in recent decades. To address the challenges associated with poor conductivity and limited electron and charge transfer capability in LDH materials, we have developed a straightforward one-pot synthesis method to successfully fabricate a composite material with a microstructure resembling cabbage, which encompasses NiFe-LDH and nanocarbon (referred as NiFe-LDH@C). Atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM) revealed that the monolayer NiFe-LDH with a height of ~0.5-0.8 nm is uniformly distributed and closely bonded to the carbon support, leading to a significant enhancement in conductivity and facilitating faster electron and charge transfer. Moreover, the NiFe-LDH@C exhibits a substantial number of surface defect sites, which enhances the interaction with oxygen species. This dual enhancement in charge transfer and oxygen species-mediated transfer greatly improves the catalytic OER performance, which is further corroborated by theoretical calculations. Notably, the Ni10Fe6-LDH@C with the highest concentration of surface oxygen vacancies demonstrated superior water oxidation performance, surpassing commercially available RuO2 catalysts; an OER overpotential of 231 mV@10 mA cm-2 with a Tafel slope of 71 mV dec-1 was achieved.

Metal-ion-assisted in-situ fabrication of large-size CoNi-LDH@MXene for robust high-energy supercapacitors

MXene has attracted substantial attention in the field of electrochemical energy storage by virtue of its excellent electrical conductivity and redox activity. Nevertheless, the interaction of hydrogen bonds and van der Waals forces in interlamination made MXene is susceptible to stack and aggregate that severely limits its practical application. In this study, cubic ZIF-67 was in-situ grown on the MXene substrate, with the assistance of a metal-ion-assisted etching strategy stepwise nucleate and grow defective LDH nanosheet arrays, resulting in the formation of large-size CoNi-LDH@MXene composite electrode. The uniformly distributed LDH nanosheet arrays feature with low angle grain boundaries and further leading to the formation of oxygen vacancies, which become reactive reaction sites and offer high-speed channels for ion migration. The large-size CoNi-LDH@MXene composite electrode exhibited a substantially improved electrochemical performance of 1420 F g−1 at 1 A/g. After being assembled into an asymmetric supercapacitor, it manifests a high energy density (energy density of 58.3 Wh kg−1 at 750 W kg−1). This work demonstrates a novel strategy for in situ fabrication of robust supercapacitor devices.

Fabrication of new in‐situ ternary nano/microcomposite LDH/Ag2O/Bayerite in trimetallic NiAg/Al layered double hydroxides for CO2 capture material

AbstractWe reported new in‐situ ternary nano/microcomposite layered double hydroxides/Ag2O/bayerite in trimetallic NiAg/Al layered double hydroxides (LDH) via hydrothermal technique; and characterization by powder X‐ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT‐IR), field emission scanning electron microscopy (FE‐SEM), energy dispersive spectroscopy (EDS), and N2 adsorption‐desorption. The formation of bayerite and silver oxide species on the LDH nanosheet depended on the excess of Al3+ and Ag+ in the solution under alkaline and hydrothermal conditions. The nitrogen isotherm adsorption profile for all ternary composites exhibited uniformity with mesoporous and lamellar characteristics. The surface area of all the composites ranged from 81.17 to 150.23 m2. g−1, the Barret‐Joyner‐Halenda (BJH) pore volume from 0.22 to 0.27 cm3. g−1, and the average pore diameter ranged from 3.47 to 5.78 nm. All composites show a laminar plate‐like structure covered with elongated pieces. The particle size of the composites ranged from 54.86 to 115.96 nm, indicating the size changed from nano to microcomposite because of the different molar ratios of Ag and Ni in the solid. The ternary composite reveals CO2 capture activity with adsorption capacity ranging from 13.93 to 19.61 mmol g−1. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Hydrogen bond-modulated copper nanocluster-aggregation-induced enhanced ECL with layered double hydroxides-sensing interface for miRNA-135b detection in colorectal cancer

Herein, we developed a novel electrochemiluminescence (ECL) sensing interface based on Mg/Fe layered double hydroxides nanosheets (LDHs) for miRNA-135b detection in human colorectal cancer tissues. The LDHs nanosheet with large specific surface area and abundant active sites can work as the electrode sensing interface to effectively catalyze the electrochemical reactions. Furthermore, the formation of hydrogen bonds between 4-carboxyphenylboronic acid (CBPA) on the copper nanoclusters (Cu NCs) and fluorine ions limited the intramolecular vibration and accelerated electron transfer, greatly improving the luminescence signal. Due to the catalysis of LDH and the aggregation-induced enhanced electrochemiluminescence (AIECL) effect, the ECL quantum yield of Cu NCs has been significantly amplified. The Mg/Fe LDH-based sensing system for miRNA-135b detection had a linear detection range of 10 fM–10 μM with a detection limit of 3.5 fM. Finally, the cancer tissue extracted from colorectal cancer patients have been successfully detected. The result indicated that the Mg/Fe LDHs sensing interface provided a new and reliable pathway for ECL analysis performance.

Interface engineering of 2D NiFe LDH/NiFeS heterostructure for highly efficient 5-hydroxymethylfurfural electrooxidation

The electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to valuable chemicals is an efficient way to upgrade biomass molecules and replace traditional catalytic synthesis. It is crucial to develop efficient and low-cost earth-abundant electrocatalysts to enhance catalytic performance of HMF oxidation. Herein, a new type of two-dimensional (2D) hybrid arrays consisting of NiFe layered double hydroxides (LDH) nanosheets and bimetallic sulfide (NiFeS) is constructed via interface engineering for efficient electrocatalytic oxidation of HMF to 2,5-furandicarboxylic acid (FDCA). The preparation process of 2D NiFe LDH/NiFeS with ultrathin heterostructure involves in anchoring a Co-based metal-organic framework (Co MOF) as template onto the carbon cloth (CC) via in-situ growth, formation of NiFe LDH on the surface of Co MOF and subsequent partial sulfidation. The electrocatalyst of NiFe LDH/NiFeS exhibits outstanding performance towards HMF oxidation, about 98.5% yield for FDCA and 97.2% Faraday efficiency (FE) in the alkaline electrolyte with 10 mmol/L HMF, as well as excellent stability retaining 90.1% FE for FDCA after six cycles test. Moreover, even at an HMF concentration of 100 mmol/L, the yield and FE for FDCA remain high at 83.6% and 93.6%, respectively. These findings highlight that 2D heterostructure containing abundant interfaces between NiFe LDH nanosheets and NiFeS can enhance the intrinsic activity of LDH and thus promote the oxidation reaction kinetics. Additionally, the synergistic effect of the bimetallic NiFe compounds also improved the selectivity of HMF conversion to FDCA. Our present work demonstrates that constructing 2D ultrathin heterostructure of NiFe LDH/NiFeS is a facile strategy via interface engineering to enhance the intrinsic activity of LDH electrocatalysts, which would open new avenues toward low-cost and advanced 2D nanocatalysts for sustainable energy conversion and electrochemical valorization of biomass derivatives.

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.

Efficient photocatalytic hydrogen production of Ni-Co layered double hydroxides (Ni-Co LDHs) anchored with reduced graphene oxide (rGO) hybrid composite

Using a suitable co-catalyst to boost photocatalytic H2 evolution from water splitting is crucial. Herein, we designed pristine NiCo-LDH and reduced graphene-oxide supported nickel-cobalt layered double hydroxide nanosheets (NiCo-LDH/rGO) as photocatalyst for the first time to evaluate the hydrogen production performance. Adding graphene has the potential to significantly increase electrical conductivity, and the supported NiCo-LDH has the potential to significantly reduce the likelihood of graphene self-aggregation. The effectiveness of its photocatalytic hydrogen generation was analyzed using a set of characterizations. The H2 evolution rates for pure rGO were 345.2 μmolh−1g−1, whereas those for Ni-Co LDH/rGO were 578.2 μmolh−1g−1. Average hydrogen generation per hour for the Ni-Co LDH/rGO composite material was 2032.1 μmolh−1g−1, which was 5.8 and 3.5 times that of rGO and Ni-Co LDH/rGO, respectively, NiCo-LDH@rGO's synergistic impact on the NiCo-LDH boosts the H2 generation pathway by increasing the catalyst's stability as well as performance by exposing active sites and speeding up electron transport. The produced nanocomposite shows excellent spatial charge separation and quicker electron transport across the conductive network of rGO, as shown by the photocurrent response test and photoluminescence (PL) spectra. The results of this study provide a fresh perspective on the practical use and synthesis of the inexpensive and effective NiCo-LDH/rGO, demonstrating the standard deviation of logical planning and preparation of high-performance photocatalysts.

Magnetron Sputtered SnO₂ Layer Combined with NiCo−LDH Nanosheets for High‐Performance All‐Solid‐State Supercapacitors

AbstractNickel‐cobalt layered double hydroxide (NiCo−LDH) has attracted much attention because of its excellent electrochemical properties and regulability. And it is a potential pseudocapacitive electrode material, which is commonly used in supercapacitors and lithium‐ion batteries. Its application in the field of supercapacitors can improve the energy density, power density and cycle life of devices. However, NiCo−LDH still faces some challenges, such as poor electrical conductivity and the capacity attenuation caused by agglomeration of layered structures, which require further research and optimization. In this paper, SnO2 films were prepared on carbon cloth (CC) by magnetron sputtering method, and Ni−Co LDH nanosheets were grown by hydrothermal reaction to obtain NiCo−LDH@SnO2 composites. Due to the synergistic effect between NiCo−LDH and SnO2, NiCo−LDH@SnO2 composites exhibit high Cs and good cyclic stability. In addition, an all‐solid‐state flexible asymmetric supercapacitor (ASC) was assembled with activated carbon (AC) anodes, showing good specific capacitance(Cs) and energy density. And a high initial capacitance can still be retained after 10,000 cycles. This paper shows that NiCo−LDH@SnO2 shows excellent application potential in supercapacitors.