Ultrathin Layered Double Hydroxide Nanosheets Research Articles

Intracellular Delivery of Therapeutic Protein via Ultrathin Layered Double Hydroxide Nanosheets.

The therapeutic application of biofunctional proteins relies on their intracellular delivery, which is hindered by poor cellular uptake and transport from endosomes to cytoplasm. Herein, we constructed a two-dimensional (2D) ultrathin layered double hydroxide (LDH) nanosheet for the intracellular delivery of a cell-impermeable protein, gelonin, towards efficient and specific cancer treatment. The LDH nanosheet was synthesized via a facile method without using exfoliation agents and showed a high loading capacity of proteins (up to 182%). Using 2D and 3D 4T1 breast cancer cell models, LDH-gelonin demonstrated significantly higher cellular uptake efficiency, favorable endosome escape ability, and deep tumor penetration performance, leading to a higher anticancer efficiency, in comparison to free gelonin. This work provides a promising strategy and a generalized nanoplatform to efficiently deliver biofunctional proteins to unlock their therapeutic potential for cancer treatment.

Bridging Au nanoclusters with ultrathin LDH nanosheets via ligands for enhanced charge transfer in photocatalytic CO2 reduction

Au nanoclusters (NCs) bring new opportunities for constructing visible-light photocatalysts for solar-driven CO2 conversion, whereas the agglomeration under illumination and lack of catalytic sites severely hinder their application. One promising approach to address the limitations is the confinement of Au NCs on a heterogeneous substrate with efficient catalytic sites, in which a concomitant bottleneck originates from the electron transfer between Au NCs and catalytic sites determining the charge transfer dynamics. Herein, we develop an effective strategy for grafting Au NCs onto ultrathin layered double hydroxide (LDH) nanosheets via engineering bridging ligands. The bridging ligands function as both surface anchors and electron mediators, which confine and stabilize Au NCs on LDH, as well as facilitate electron transfer from Au NCs to catalytic sites. As a result, the durability and efficiency for photocatalytic CO2 reduction is significantly enhanced. This work provides a fresh hint for stabilizing ultrasmall nanoclusters and facilitating the electron transfer between light-harvesting nanoclusters and catalytic sites through bridging ligands.

Ultrathin NiFe-LDH nanosheets strongly coupled with MOFs-derived hybrid carbon nanoflake arrays as a self-supporting bifunctional electrocatalyst for flexible solid Zn-air batteries

The construction of a hybrid hierarchical architecture is a promising strategy for optimizing the electrocatalytic activity and the performance of flexible Zn-air battery. However, it still remains a challenging task. This study reports on the use of a simple approach in the preparation of a flexible 3D self-supporting bifunctional catalyst. Ultrathin NiFe-based layered double hydroxide nanosheets (NiFe-LDH) have in this approach been strongly coupled to a metal-organic framework (MOF)-derived carbon nanoflake array, to be used in flexible Zn-air batteries. Importantly, the introduction of Co nanoparticles that were anchored onto the nitrogen-doped porous carbon (Co-NC) nanoflakes provided an abundance of active sites for the oxygen reduction reaction (ORR). Moreover, the catalytic oxygen evolution reaction (OER) process was improved by altering the local electronic structure of the Ni and Fe species in NiFe-LDH. The 3D interconnected conductive network structure, in addition to the strong coupling between NiFe-LDH and Co-NC, was found to give a catalyst with superior electrocatalytic OER performances. The overpotential was only 284 mV at 50 mA cm−2 in an alkaline medium, which is a result that outperforms the commercial RuO2 catalyst. This bifunctional catalyst did also exhibit a good catalytic performance that is comparable to that of commercial Pt/C towards ORR. Interestingly, when this catalyst was used as binder-free air cathode, the assembled flexible solid-state Zn-air battery demonstrated a favorable power density, cycling stability, and mechanical flexibility. The present work offers a facile and efficient strategy for the development and construction of self-supporting bifunctional OER/ORR electrocatalysts, to be used in wearable and flexible electronic devices.

Universal Strategy for Preparing Highly Stable PBA/Ti3C2Tx MXene toward Lithium-Ion Batteries via Chemical Transformation.

Prussian blue analogues (PBAs) are believed to be intriguing anode materials for Li+ storage because of their tunable composition, designable topologies, and tailorable porous structures, yet they suffer from severe capacity decay and inferior cycling stability due to the volume variation upon lithiation and high electrical resistance. Herein, we develop a universal strategy for synthesizing small PBA nanoparticles hosted on two-dimensional (2D) MXene or rGO (PBA/MX or PBA/rGO) via an in situ transformation from ultrathin layered double hydroxides (LDH) nanosheets. 2D conductive nanosheets allow for fast electron transport and guarantee the full utilization of PBA even at high rates; at the meantime, PBA nanoparticles effectively prevent 2D materials from restacking and facilitate rapid ion diffusion. The optimized Ni0.8Mn0.2-PBA/MX as an anode for lithium-ion batteries (LIBs) delivers a capacity of 442 mAh g-1 at 0.1 A g-1 and an excellent cycling robustness in comparison with bare PBA bulk crystals. We believe that this study offers an alternative choice for rationally designing PBA-based electrode materials for energy storage.

Ultrathin Nanosheet-Supported Ag@Ag2O Core-Shell Nanoparticles with Vastly Enhanced Photothermal Conversion Efficiency for NIR-II-Triggered Photothermal Therapy.

Photothermal therapy (PTT) working in the second near-infrared (NIR-II) region has aroused a huge interest due to its potential application in terms of clinical cancer treatment. However, owing to the lack of photothermal nanoagents with high photothermal conversion efficiency, NIR-II-driven PTT still suffers from poor efficiency and subsequent cancer recurrence. In this work, we show a new and highly efficient preparation approach for NIR-II photothermal nanoagents and tailor ultrathin layered double hydroxide (LDH)-supported Ag@Ag2O core-shell nanoparticles (Ag@Ag2O/LDHs-U), vastly improving NIR-II photothermal performance. A combination study (high-resolution transmission electron microscopy (HRTEM), extended X-ray absorption fine structure spectroscopy (EXAFS), and X-ray photoelectron spectroscopy (XPS)) verifies that ultrafine Ag@Ag2O core-shell nanoparticles (∼3.8 nm) are highly dispersed and firmly immobilized within ultrathin LDH nanosheets, and their Ag2O shell possesses abundant vacancy-type defects. These unique Ag@Ag2O/LDHs-U display an impressive photothermal conversion efficiency as high as 76.9% at 1064 nm. Such an excellent photothermal performance is likely attributed to the enhanced localized surface plasmon resonance (LSPR) coupling effect between Ag and Ag2O and the reduced band gap caused by vacancy-type defects in the Ag2O shell. Meanwhile, Ag@Ag2O/LDHs-U also show prominent photothermal stability, due to the unique supported core-shell nanostructure. Moreover, both in vitro and in vivo studies further confirm that Ag@Ag2O/LDHs-U possess good biocompatible properties and outstanding PTT therapeutic efficacy in the NIR-II region. This research shows a new strategy in the rational design and preparation of an efficient photothermal agent, which is helpful to achieve more accurate and effective cancer theranostics.

Co2 Methanation Over Catalyst Derived from Ultrathin Nizral Layered Double Hydroxide Nanosheets Precursor

Co2 Methanation Over Catalyst Derived from Ultrathin Nizral Layered Double Hydroxide Nanosheets Precursor

Hierarchical ultrathin NiFe-borate layered double hydroxide nanosheets encapsulated into biomass-derived nitrogen-doped carbon for efficient electrocatalytic oxygen evolution

Exploring highly efficient, cost-effective, and stable electrocatalysts toward oxygen evaluation reaction (OER) is of great significance for hydrogen generation. Herein, in situ growth of NiFe-borate layered double hydroxide (NiFe-BLDH) nanosheets on waste biomass-derived nitrogen-doped carbon (NC) with hierarchical architecture under microwave hydrothermal conditions is reported. The as-synthesized NiFe-borate layered double hydroxide/nitrogen-doped carbon (NiFe-BLDH/NC) exhibits outstanding OER activity, showing an extremely low overpotential of 243 mV at the current density of 10 mA cm−2 and a relatively small Tafel slope of 42.7 mV dec−1, which are superior to the commercial RuO2 and many previously reported NiFe-LDH-based OER electrocatalysts. Additionally, the catalyst also shows remarkable stability with unobvious decrease of current density over a period of 24 h. These excellent catalytic performances could be attributable to the synergistic effects between the conductive NC scaffold and NiFe-BLDH with excellent hydrophilicity caused by the intercalated borate anions, which provide many advantages, such as large surface area, abundant active sites, fast charge and mass transport pathways. This work provides new insights into the design and facile preparation green and efficient electrocatalysts

Electrochemical sensing for naphthol isomers based on the in situ growth of zeolitic imidazole framework-67 on ultrathin CoAl layered double hydroxide nanosheets by a reaction–diffusion technique

It is established that ultrathin layered double hydroxide nanosheets (LDHNS) and zeolitic imidazole frameworks (ZIF) are desirable electrochemical sensing modifiers owing to their large surface area and abundant catalytic sites. Integration of them is thus an effective solution to maximize their electrocatalytic activity. Herein, a novel reaction–diffusion framework (RDF) technique is applied for the in situ growth of ZIF-67 on ultrathin CoAl-LDHNS (CoAl-LDHNS@ZIF-67). In a confined space of the agar gel matrix of RDF, the coordination reaction between organic ligands and CoAl-LDHNS without an additional Co2+ source achieves the controllable growth of ZIF-67 crystals through a long vertical diffusion. The prepared composite comprises both CoAl-LDHNS and ZIF-67 components with a certain ratio and provides a large surface area and amply catalytic sites, thus realizing a rapid transfer of electron and mass. The CoAl-LDHNS@ZIF-67 modified electrode is employed for the simultaneous detection of naphthol isomers by differential pulse voltammetry. Naphthol isomers display anodic reactions with a wide peak potential difference, allowing their simultaneous detection feasible. Voltammetric responses of α-naphthol and β-naphthol follow good linearity against the concentration in a wide range from 0.3 to 150 μM with limits of detection of 54 and 82 nM, respectively. The proposed sensor also demonstrates excellent selectivity, stability, reproducibility, and practicability for the simultaneous detection of naphthol isomers.

Ultrathin Layered Double Hydroxide Nanosheets Enabling Composite Polymer Electrolyte for All‐Solid‐State Lithium Batteries at Room Temperature

AbstractSolid electrolytes are the most promising substitutes for liquid electrolytes to construct high‐safety and high‐energy‐density energy storage devices. Nevertheless, the poor lithium ion mobility and ionic conductivity at room temperature (RT) have seriously hindered their practical usage. Herein, single‐layer layered‐double‐hydroxide nanosheets (SLN) reinforced poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) composite polymer electrolyte is designed, which delivers an exceptionally high ionic conductivity of 2.2 × 10−4 S cm−1 (25 °C), superior Li+ transfer number (≈0.78) and wide electrochemical window (≈4.9 V) with a low SLN loading (≈1 wt%). The Li symmetric cells demonstrate ultra‐long lifespan stable cycling over ≈900 h at 0.1 mA cm−2, RT. Moreover, the all‐solid‐state Li|LiFePO4 cells can run stably with a high capacity retention of 98.6% over 190 cycles at 0.1 C, RT. Moreover, using LiCoO2/LiNi0.8Co0.1Mn0.1O2, the all‐solid‐state lithium metal batteries also demonstrate excellent cycling at RT. Density functional theory calculations are performed to elucidate the working mechanism of SLN in the polymer matrix. This is the first report of all‐solid‐state lithium batteries working at RT with PVDF‐HFP based solid electrolyte, providing a novel strategy and significant step toward cost‐effective and scalable solid electrolytes for practical usage at RT.

Ultrathin defective high-entropy layered double hydroxides for electrochemical water oxidation

The ultrathin defective high-entropy layered double hydroxides (HE-LDHs) nanosheets, having multifarious and near-continuous catalytic sites, can be used for a new platform for electrochemical oxygen evolution.

Composition controllable fabrication of ultrathin 2D CoMn layered double hydroxides for highly efficient electrocatalytic oxygen evolution

Oxygen evolution reaction (OER) is an important half-cell reaction of water splitting. The OER involves a multiple proton-coupled electron transfer process, which leads to the sluggish kinetic reaction. Searching for highly efficient route to synthesize electrocatalysts for OER is significant for developing sustainable energy systems. Herein, the 2D ultrathin cobalt-manganese layered double hydroxides (CoMn-LDHs) nanosheets with a typical hydrotalcite structure are prepared by a specific reduction–oxidation method. Particularly, the Co8Mn2-LDH electrocatalyst exhibits the highest activity along with a large surface area of 276.9 m2/g among different Co/Mn ratios of the CoMn-LDHs. The as-prepared Co8Mn2-LDH shows an overpotential as low as 307 mV at the 10 mA/cm2 current density and a small Tafel slope of 86 mV/dec. The Co8Mn2-LDH still maintains a satisfactory durability after a long-term continuous measurement. Such excellent electrocatalytic performance may be attributed to the huge surface area and the unique layered structure, which will do favor to the charge transport between the interface of solution and catalyst. Therefore, the reduction–oxidation method provides a highly efficient route to synthesize LDHs for OER.

Visible-Light-Induced Hydrogenation of C═C Bonds by Hydrazine over Ultrathin Layered Double Hydroxide Nanosheets

The reduction of C═C is of great importance, while H2 is the most widely used source usually in the harsh condition in the industry. However, under mild conditions, the H2-free reduction of C═C bon...

In situ growth of ZIF-67 on ultrathin CoAl layered double hydroxide nanosheets for electrochemical sensing toward naphthol isomers

Zeolitic imidazole frameworks (ZIF) and ultrathin layered double hydroxide nanosheets (LDHNS) have drawn growing attention in the electrocatalysis field. Combining the merits and maximizing the electrocatalytic activity of each building block in the corresponding composite is imperative but challenging. This work thus proposes a simple strategy for the in situ growth of ZIF-67 on ultrathin CoAl-LDHNS (LDHNS@ZIF-67) without an additional Co2+ source. Thanks to the ultrathin nature, CoAl-LDHNS provide more Co reactive sites for the ordered growth of ZIF-67 nanocrystals on this 2D matrix via coordination interactions between Co2+ and 2-methylimidazole. The obtained LDHNS@ZIF-67 provides more convenient pathways to rapid electron transportation between the basal electrode and analytes. Hence, the modified electrode can be applied for the truly simultaneous detection of naphthol isomers by differential pulse voltammetry. α-naphthol and β-naphthol exhibit irreversible oxidation peaks at 0.327 and 0.487 V vs. saturated calomel electrode, respectively, making their simultaneous detection feasible. The voltammetric responses of both isomers are linear in concentrations ranging from 0.3 to 150 μM with limits of detection of 62 and 94 nM, respectively. The sensor exhibits advantages including good reproducibility, stability, selectivity, and practicability for the simultaneous detection of naphthol isomers in real water samples.

600 nm Irradiation-Induced Efficient Photocatalytic CO2 Reduction by Ultrathin Layered Double Hydroxide Nanosheets

Currently, developing effective photocatalysts for reducing CO2 to commercial chemicals and fuels has aroused great interest. However, rates of photocatalytic CO2 reduction remain too low to arouse...

Electrochemical transformation of Prussian blue analogues into ultrathin layered double hydroxide nanosheets for water splitting.

Herein, we demonstrate a template directed route for the synthesis of self-supported cobalt-iron based Prussian blue analogues (PBAs). The PBAs are electrochemically transformed into layered double hydroxides to produce excellent water oxidation and hydrogen evolution activity, while the overall water splitting is attained at a cell voltage of 1.58 V to reach 20 mA cm-2 current density.

Photo-induced charge kinetic acceleration in ultrathin layered double hydroxide nanosheets boosts the oxygen evolution reaction

Photo-electro-integrated activation over LDH catalysts was demonstrated as an effective strategy to boost OER activity with free solar energy.

One‐Step Synthesis of Ultrathin NiMn Layered Double Hydroxide Nanosheets for Supercapacitors

AbstractWith the help of ethylenediamine (EN), we built through hydrothermal synthesis a multiple‐level NiMn layered double hydroxide nanostructure consisting of ultrathin nanosheets (UNML) with plenty buffer spaces. Such porous structure provides more active sites, shortens the diffusion path of electrolyte ions, and creates massive “live volume” to ensure structural integrity during long‐term cycling. The UNML possesses high specific capacitance (1513 F g−1 at 1 A g−1). Moreover, the hybrid supercapacitor employing UNML and AC as positive and negative electrode delivers enhanced energy density up to 59 Wh kg−1 at a power density of 808 W kg−1 and robust cycling stability with capacitance degradation of 8.7 % after 5000 cycles. This simple strategy is expected to cope with the prevalent issues facing battery‐type electrode materials, ensuring improvement of the overall electrochemical performance.

Hierarchical NiMn-layered double hydroxides@CuO core-shell heterostructure in-situ generated on Cu(OH)2 nanorod arrays for high performance supercapacitors

Supercapacitors are attracting tremendous research interest because they are expected to achieve battery-level energy density while having long calendar life and short charging time. Ultrathin layered double hydroxide nanosheets (LDHs) are promising candidates as electrode materials for energy storage. Herein, we have successfully designed and synthesized a hierarchical NiMn-LDH@CuO/CF core-shell heterostructure which comprises a vertical and intercrossing ultrathin NiMn-LDHs nanosheets shell and a slightly curly and tops tangled CuO nanowires core. The synthesized NiMn-LDH@CuO/CF electrode exhibits a high areal capacitance of 6077 mF cm−2 (2430.8 F g−1) at a current density of 2 mA cm−2 (0.8 A g−1), which is significant higher than those of CF, Cu(OH)2/CF, CuO/CF, NiMn-LDH/CF and NiMn-LDH electrodes. Moreover, a superior cycling stability of 89.22% retention after 8000 cycles at a high current density of 50 mA cm−2 is observed and a low internal resistance Rs (0.584 Ω) can be achieved. Furthermore, an all solid-state asymmetric supercapacitor (ASC) device based on the as-synthesized hierarchical NiMn-LDH@CuO/CF core-shell heterostructure hybrid material as positive electrode and activated carbon as negative electrode is successfully fabricated and exhibits an energy density of 10.8 W h kg−1 at a power density of 100 W kg−1. Additionally, a LED indicator can be lit up for eight minutes when three ASCs are connected in series. The excellent electrochemical performances can be credited to the significant enhancement of the specific surface area, charge transport and mechanical stability resulted from the ultrathin LDH shell, the highly conductive CuO nanowires core-shell nanostructure. This strategy for the fabrication of hierarchical core-shell heterostructure could have enormous potential for applications in high performance energy storage devices.

Novel Ultrathin Layered Double Hydroxide Nanosheets with In Situ Formed Oxidized Phosphorus as Anions for Simultaneous Fire Resistance and Mechanical Enhancement of Thermoplastic Polyurethane

Thermoplastic polyurethane (TPU) is widely used in wires, cables, etc., facing a big challenge in its fire safety under many cases. Traditional nanoparticles with a flame-retardant feature are show...

In situ growth of ultrathin NiFe layered double hydroxide nanosheets on reduced oxide graphene as an enhanced oxygen evolution electrocatalyst

It is highly essential but challengeable to explore the earth-abundant and low-cost oxygen evolution reaction catalysts to replace Ir- or/and Ru-based ones. In this article, we report an in situ growth of ultrathin NiFe layered double hydroxide nanosheets on reduced graphene oxide in formamide aqueous solution followed by simple chemical reduction. These ultrathin layered double hydroxide nanosheets in the composite occur in single- or multi-layer forms on reduced graphene oxide matrix. Consequently, the obtained catalyst exhibits the enhanced BET surface area and electrochemically active surface area, and low mass transfer resistance. This electrocatalyst displays the excellent OER activity with a small onset potential of 233 mV. Additionally, it only requires an overpotential of 254 mV to achieving current density of 10 mA cm−2, and can gives a current density of 70.60 mA cm−2 at overpotential of 300 mV in 0.1 M KOH. It also demonstrates the robust long-time electrochemical durability.