Tuning CuMgAl-Layered Double Hydroxide Nanostructures to Achieve CH4 and C2+ Product Selectivity in CO2 Electroreduction.

Electrochemical CO2 reduction reaction (eCO2RR) over Cu-based catalysts is a promising approach for efficiently converting CO2 into value-added chemicals and alternative fuels. However, achieving controllable product selectivity from eCO2RR remains challenging because of the difficulty in controlling the oxidation states of Cu against robust structural reconstructions during the eCO2RR. Herein, we report a novel strategy for tuning the oxidation states of Cu species and achieving eCO2RR product selectivity by adjusting the Cu content in CuMgAl-layered double hydroxide (LDH)-based catalysts. In this strategy, the highly stable Cu2+ species in low-Cu-containing LDHs facilitated the strong adsorption of *CO intermediates and further hydrogenation into CH4. Conversely, the mixed Cu0/Cu+ species in high-Cu-containing LDHs derived from the electroreduction during the eCO2RR accelerated C-C coupling reactions. This strategy to regulate Cu oxidation states using LDH nanostructures with low and high Cu molar ratios produced an excellent eCO2RR performance for CH4 and C2+ products, respectively.

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 -58.1 dB at 15.8 GHz at a thickness of 2.1 mm, and a broad effective absorption bandwidth (EAB) value of 7.3 GHz is achieved at 2.5 mm. 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.

Directional Activation of Oxygen by the Au-Loaded ZnAl-LDH with Defect Structure for Highly Efficient Photocatalytic Oxidative Coupling of Methane.

Photocatalytic oxidative coupling of CH4 (OCM) is a promising CH4 conversion process that can achieve efficient methane conversion with the assistance of O2. It remains to be highly challenging to improve the photocatalytic OCM activity from catalyst design and to deepen the understanding of the reactant activation in the OCM process. In this work, the Au-loaded ZnAl-layered double hydroxides (LDHs) with and without oxygen vacancy are constructed (denoted as Au/ZnAl and Au/ZnAl-v), respectively. When applied for photocatalytic OCM, the Au/ZnAl-v shows a CH4 conversion rate of 8.5 mmol g-1 h-1 with 92% selectivity of C2H6 at 40 °C, outperforming most reported photocatalytic OCM systems at low temperature reported in the literature. Furthermore, the catalytic performance of Au/ZnAl-v can be stable for 100 h. In contrast, the An/ZnAl exhibits a CH4 conversion rate of 0.8 mmol g-1 h-1 with 46% selectivity of C2H6. Detailed characterizations and DFT calculation studies reveal that the introduced Ov sites on Au/ZnAl-v are able to activate O2, and the resulting superoxide radical O2·- greatly promotes the activation of CH4. The coupling of CH3· groups with the assistance of Au cocatalyst leads to the formation of C2H6 with high photocatalytic activity.

Tuning Iron Active Sites of FeOOH via Al3+ and Heteroatom Doping-Induced Asymmetric Oxygen Vacancy Electronic Structure for Efficient Alkaline Water Splitting.

Oxygen evolution reaction is the essential anodic reaction for water splitting. Designing tunable electronic structures to overcome its slow kinetics is an effective strategy. Herein, the molecular ammonium iron sulfate dodecahydrate is employed as the precursor to synthesize the C, N, S triatomic co-doped Fe(Al)OOH on Ni foam (C,N,S-Fe(Al)OOH-NF) with asymmetric electronic structure. Both in situ oxygen vacancies and their special electronic configuration enable the electron transfer between the d-p orbitals and get the increase of OER activity. Density functional theory calculation further indicates the effect of electronic structure on catalytic activity and stability at the oxygen vacancies. In alkaline solution, the catalyst C,N,S-Fe(Al)OOH-NF shows good catalytic activity and stability for water splitting. For OER, the overpotential of 10 mA cm-2 is 264 mV, the tafel slope is 46.4 mV dec-1, the HER overpotential of 10 mA cm-2 is 188 mV, the tafel slope is 59.3 mV dec-1. The stability of the catalyst can maintain ≈100 h. This work has extraordinary implications for understanding the mechanistic relationship between electronic structure and catalytic activity for designing friendly metal (oxy)hydroxide catalysts.

Modulation Engineering of Electromagnetic Wave Absorption Performance of Layered Double Hydroxides Derived Hollow Metal Carbides Integrating Corrosion Protection.

Layered double hydroxides (LDHs) with unique layered structure and atomic composition are limited in the field of electromagnetic wave absorption (EMA) due to their poor electrical conductivity and lack of dielectric properties. In this study, the EMA performance and anticorrosion of hollow derived LDH composites are improved by temperature control and composition design using ZIF-8 as a sacrifice template. Diverse regulation modes result in different mechanisms for EMA. In the temperature control process, chemical reactions tune the composition of the products and construct a refined structure to optimize the LDHs conductivity loss. Additionally, the different phase interfaces generated by the control components optimize the impedance matching and enhance the interfacial polarization. The results show that the prepared NCZ (Ni3ZnC0.7/Co3ZnC@C) has a minimum reflection loss (RLmin ) of -58.92 dB with a thickness of 2.4 mm and a maximum effective absorption bandwidth (EABmax ) of 7.36 GHz with a thickness of 2.4 mm. Finally, due to its special structure and composition, the sample exhibits excellent anticorrosion properties. This work offers essential knowledge for designing engineering materials derived from metal organic framework (MOF) with cutting-edge components and nanostructures.

Thermally Stable High-Entropy Layered Double Hydroxides for Advanced Catalysis.

Layered double hydroxides (LDHs), especially high-entropy LDHs (HE-LDHs), have gained increasing attention. However, HE-LDHs often possess poor thermal stability, restricting their applications in thermo-catalysis. Herein, a novel complexing nucleation method is proposed for engineering HE-LDHs with enhanced thermal stability. This approach precisely controls the nucleation of metal ions with different solubility products, achieving homogeneous nucleation and effectively mitigating phase segregation and transformation at elevated temperatures. The prepared HE-LDH sample demonstrated exceptional thermal stability at temperatures up to 300 °C, outperforming all previously reported LDHs. Importantly, these HE-LDHs preserve both Lewis and Brønsted acidic sites, enabling the 100% removal of aromatic sulfides and alkaline nitrogen compounds from fuel oils in thermo-catalytic oxidation reactions. Experimental and characterization findings reveal that the metal-hydroxide bonds in the prepared HE-LDHs are strengthened by associated hydroxyl groups, inducing negative thermal expansion and augmenting the presence of acidic sites, thereby ensuring structural stability and enhancing catalytic activity. This study not only proposes a strategy for engineering HE-LDHs with remarkable thermal stability but also highlights potential applications of LDHs in thermo-catalysis.

Tannic Acid Selective Modulation Defects to Enhance the Photocatalytic CO2 Reduction Activity of Layered Double Hydroxides.

Recently, layered double hydroxides (LDH) have shown great potential in photoreduction of CO2 owing to its flexible structural adjustability. In this study, the mild acidic property of tannic acid (TA) is exploited to etch the bimetal LDH to create abundant vacancies to gain the coordination unsaturated active centers. Based on the different chelating abilities of TA to various metal ions, the active metals are remained by selective chelation while the inert metals are removed during the etching process of bimetal LDH. Furthermore, selective chelating with metal ions not only increases the percentage of highly active metals but also compensates for the structural damage caused by the etch, which achieves a scalpel-like selective construction of vacancies. The NiAl-LDH etched and functionalized by TA for 3 h exhibits superior photo-reduction of CO2 performance without co-catalysts and photo-sensitizers, which is 14 times that of the pristine NiAl-LDH. The fact that many bimetal LDHs can be functionalized by TA and exhibit significantly improved photocatalytic efficiency is confirmed, suggesting this strategy is generalized to functionalize double- or multi-metal LDH. The method provided in this work opens the door for polyphenol-functionalized LDHs to enhance their ability for light-driven chemical transformations.

PAD4 Inhibitor-Loaded Layered Double Hydroxide Nanosheets as a Multifunctional Nanoplatform for Photodynamic Therapy-Mediated Tumor Metastasis Treatment.

Photodynamic therapy (PDT) is demonstrated to be effective in inducing antitumor immune responses for tumor metastasis treatment. However, tumor hypoxia, inferior tissue penetration of light, and low singlet oxygen (1O2) quantum yield significantly hamper the efficacy of PDT, thus weakening its immune function. Moreover, PDT-mediated neutrophil extracellular traps (NETs) formation can further reduce the therapeutic effectiveness. Herein, the use of defect-rich CoMo-layered double hydroxide (DR-CoMo-LDH) nanosheets as a carrier to load a typical peptidyl arginine deiminase 4 inhibitor, i.e., YW4-03, to construct a multifunctional nanoagent (403@DR-LDH) for PDT/immunotherapy, is reported. Specifically, 403@DR-LDH inherits excellent 1O2 generation activity under 1550 nm laser irradiation and improves the half-life of YW4-03. Meanwhile, 403@DR-LDH plus 1550 nm laser irradiation can stimulate immunogenic cell death to promote the maturation of dendric cells and activation/infiltration of T cells and significantly downregulate H3cit protein expression to inhibit NETs formation, synergistically promoting the antitumor metastasis effect. Taken together, 403@DR-LDH can kill cancer cells and inhibit tumor growth/metastasis under 1550 nm laser irradiation. Single-cell analysis indicates that 403@DR-LDH can regulate the ratio of immune cells and immune-related proteins to improve the tumor immune microenvironment, showing strong efficacy to inhibit the tumor growth, metastasis, and recurrence.

Electrochemical Deposition for Cultivating Nano- and Microstructured Electroactive Materials for Supercapacitors: Recent Developments and Future Perspectives.

The globe is currently dealing with serious issues related to the world economy and population expansion, which has led to a significant increase in the need for energy. One of the most promising energy devices for the next generation of energy technology is the supercapacitor (SC). Among the numerous nanostructured materials examined for SC electrodes, inorganic nanosheets are considered to be the most favorable electrode materials because of their excellent electrochemical performance due to their large surface area, very low layer thickness, and tunable diverse composition. Various inorganic nanosheets (NS) such as metal oxides, metal chalcogenides, metal hydroxides, and MXenes show substantial electrochemical activity. Herein, a comprehensive survey of inorganic NS arrays synthesized through the electrodeposition method is reported with the discussion on detailed growth mechanism and their application in the fabrication of SC electrodes/devices for powering flexible and wearable electronics appliances. To begin with, the first section will feature the various types of electrodeposition working mechanism, SC types and their working mechanisms, importance of nanosheet structure for SCs. This review gives a profound interpretation of supercapacitor electrode materials and their performances in different domains. Finally, a perspective on NS array through electrodeposition method applications in diverse fields is extensively examined.

Controllable Electronic Transfer Tailoring d-band Center via Cobalt-Oxygen-Bridged Ru/Fe Dual-sites for Boosted Oxygen Evolution.

Rational tailoring of the electronic structure at the defined active center of reconstructed metal (oxy)hydroxides (MOOH) during oxygen evolution reaction (OER) remains a challenge. With the guidance of density functional theory (DFT), herein a dual-site regulatory strategy is reported to tailor the d-band center of the Co site in CoOOH via the controlled electronic transfer at the Ru─O─Co─O─Fe bonding structure. Through the bridged O2- site, electrons are vastly flowed from the t2g-orbital of the Ru site to the low-spin orbital of the Co site in the Ru-O-Co coordination and further transfer from the strong electron-electron repulsion of the Co site to the Fe site by the Co-O-Fe coordination, which balancing the electronic configuration of Co sites to weaken the over-strong adsorption energy barrier of OH* and O*, respectively. Benefiting from the highly active of the Co site, the constructed (Ru2Fe2Co6)OOH provide an extremely low overpotential of 248 mV and a Tafel slope of 32.5 mV dec-1 at 10 mA cm-2 accompanied by long durability in alkaline OER, far superior over the pristine and Co-O-Fe bridged CoOOH catalysts. This work provides guidance for the rational design and in-depth analysis of the optimized role of metal dual-sites.

Advanced High-Energy All-Solid-State Hybrid Supercapacitor with Nickel-Cobalt-Layered Double Hydroxide Nanoflowers Supported on Jute Stick-Derived Activated Carbon Nanosheets.

Developing efficient, lightweight, and durable all-solid-state supercapacitors is crucial for future energy storage systems. The study focuses on optimizing electrode materials to achieve high capacitance and stability. This study introduces a novel two-step pyrolysis process to synthesize activated carbon nanosheets from jute sticks (JAC), resulting in an optimized JAC-2 material with a high yield (≈24%) and specific surface area (≈2600 m2 g-1). Furthermore, an innovative in situ synthesis approach is employed to synthesize hybrid nanocomposites (NiCoLDH-1@JAC-2) by integrating JAC nanosheets with nickel-cobalt-layered double hydroxide nanoflowers (NiCoLDH). These nanocomposites serve as positive electrode materials and JAC-2 as the negative electrode material in all-solid-state asymmetric hybrid supercapacitors (HSCs), exhibiting remarkable performance metrics. The HSCs achieve a specific capacitance of 750 F g-1, a specific capacity of 209 mAh g-1 (at 0.5 A g-1), and an energy density of 100 Wh kg-1 (at 250 W kg-1) using PVA/KOH solid electrolyte, while maintaining outstanding cyclic stability. Importantly, a density functional theory framework is utilized to validate the experimental findings, underscoring the potential of this novel approach for enhancing HSC performance and enabling the large-scale production of transition metal-based layered double hydroxides.

Enhanced Ion Transport Through Mesopores Engineered with Additional Adsorption of Layered Double Hydroxides Array in Alkaline Flow Batteries.

Efficient mass transfer in electrodes is essential for the electrochemical processes of battery charge and discharge, especially at high rates and capacities. This study introduces a 3D electrode design featuring layered double hydroxides (LDHs) nanosheets array grown in situ on a carbon felt surface for flow batteries. The mesoporous structure and surface characteristic of LDH nanosheets, especially, the hydroxyl groups forming a unique "H-bonding-like" geometry with ferrous cyanide ions, facilitate efficient adsorption and ion transport. Thus, the designed LDHs electrode enables the alkaline zinc-iron flow battery to maintain a voltage efficiency of 81.6% at an ultra-high current density of 320 mA cm-2, surpassing the values reported in previous studies. The energy efficiency remains above 84% after 375 cycles at a current density of 240 mA cm-2. Molecular dynamics simulations verify the enhanced adsorption effect of LDH materials on active ions, thus facilitating ion transport in the battery. This study provides a novel approach to improve mass transport in electrodes for alkaline flow batteries and other energy storage devices.

In Situ Synthesis of High-Entropy (Oxy)Hydroxides Via Electrochemical Reconfiguration As Catalysts For Efficient Water Oxidation.

Surface reconstruction plays a pivotal role in enhancing the activity of the oxygen evolution reaction (OER), particularly in terms of the structural transformation from metal oxides to (oxy)hydroxides. Herein, a novel (oxy)hydroxide (FeCoNiCuMoOOH) with high entropy is developed by the electrochemical reconstitution of corresponding oxide (FeCoNiCuMoOx). Significantly, the FeCoNiCuMoOOH exhibits much higher OER electrocatalytic activity and durability with an overpotential as low as 201 mV at a current density of 10 mA cm-2, and with a Tafel slope of 39.4 mV dec-1. The FeCoNiCuMoOOH/NF presents high stability when testing under a constant current at 100 mA cm-2 within 1000 h. The surface reconstruction is a process of dissolution-reprecipitation of Cu and Mo species and co-hydroxylation of five metal species, which ultimately leads to the formation of FeCoNiCuMoOOH from FeCoNiCuMoOx. This study holds great significance in the realm of designing high-entropy (oxy)hydroxides catalysts with exceptional activity and stability for OER.

Tailoring Mott-Schottky RuO2/MgFe-LDH Heterojunctions in Electrospun Microfibers: A Bifunctional Electrocatalyst for Water Electrolysis.

Hydrogen is a fuel of the future that has the potential to replace conventional fossil fuels in several applications. The quickest and most effective method of producing pure hydrogen with no carbon emissions is water electrolysis. Developing highly active electrocatalysts is crucial due to the slow kinetics of oxygen and hydrogen evolution, which limit the usage of precious metals in water splitting. Interfacial engineering of heterostructures has sparked widespread interest in improving charge transfer efficiency and optimizing adsorption/desorption energetics. The emergence of a built-in-electric field between RuO2 and MgFe-LDH improves the catalytic efficiency toward water splitting reaction. However, LDH-based materials suffer from poor conductivity, necessitating the design of 1D materials by integration of RuO2/ MgFe-LDH to enhance catalytic properties through large surface areas and high electronic conductivity. Experimental results demonstrate lower overpotentials (273 and 122 mV at 10 mA cm-2) and remarkable stability (60 h) for the RuO2/MgFe-LDH/Fiber heterostructure in OER (1 m KOH) and HER (0.5 m H2SO4) reactions. Density functional theory (DFT) unveils a synergistic mechanism at the RuO2/MgFe-LDH interface, leading to enhanced catalytic activity in OER and improved adsorption energy for hydrogen atoms, thereby facilitating HER catalysis.

Bifunctional Bismuth-Based Layered Double Hydroxide Sonosensitizer for Magnetic Resonance Imaging-Guided Sonodynamic Cancer Therapy.

Novel inorganic sonosensitizers with excellent reactive oxygen species (ROS) generation activity and multifunctionality are appealing in sonodynamic therapy (SDT). Herein, amorphous bismuth (Bi)-doped CoFe-layered double hydroxide (a-CoBiFe-LDH) nanosheets are proposed via crystalline-to-amorphous phase transformation strategy as a new type of bifunctional sonosensitizer, which allows ultrasound (US) to trigger ROS generation for magnetic resonance imaging (MRI)-guided SDT. Importantly, a-CoBiFe-LDH nanosheets exhibit much higher ROS generation activity (≈6.9 times) than that of traditional TiO2 sonosensitizer under US irradiation, which can be attributed to the acid etching-induced narrow band gap, high electron (e-)/hole (h+) separation efficiency and inhibited e-/h+ recombination. In addition, the paramagnetic properties of Fe ion endow a-CoBiFe-LDH with excellent MRI contrast ability, making it a promising contrast agent for T2-weighted MRI. After modification with polyethylene glycol, a-CoBiFe-LDH nanosheets can function as a high-efficiency sonosensitizer to activate p53, MAPK, oxidative phosphorylation, and apoptosis-related signaling pathways, ultimately inducing cell apoptosis in vitro and tumor ablation in vivo under US irradiation, which shows great potential for clinical cancer treatment.

Nickel Hydroxide-Based Electrocatalysts for Promising Electrochemical Oxidation Reactions: Beyond Water Oxidation.

Transition metal hydroxides have attracted significant research interest for their energy storage and conversion technique applications. In particular, nickel hydroxide (Ni(OH)2), with increasing significance, is extensively used in material science and engineering. The past decades have witnessed the flourishing of Ni(OH)2-based materials as efficient electrocatalysts for water oxidation, which is a critical catalytic reaction for sustainable technologies, such as water electrolysis, fuel cells, CO2 reduction, and metal-air batteries. Coupling the electrochemical oxidation of small molecules to replace water oxidation at the anode is confirmed as an effective and promising strategy for realizing the energy-saving production. The physicochemical properties of Ni(OH)2 related to conventional water oxidation are first presented in this review. Then, recent progress based on Ni(OH)2 materials for these promising electrochemical reactions is symmetrically categorized and reviewed. Significant emphasis is placed on establishing the structure-activity relationship and disclosing the reaction mechanism. Emerging material design strategies for novel electrocatalysts are also highlighted. Finally, the existing challenges and future research directions are presented.

Unraveling the Dynamic Reconstruction of Active Co(IV)-O Sites on Ultrathin Amorphous Cobalt-Iron Hydroxide Nanosheets for Efficient Oxygen-Evolving.

Highly-efficient and cost-effective electrocatalysts toward the oxygen evolution reaction (OER) are crucial for advancing sustainable energy technologies. Herein, a novel approach leveraging corrosion engineering is presented to facilitate the in situ growth of amorphous cobalt-iron hydroxides on nickel-iron foam (CoFe(OH)x-m/NFF) within a NaCl-CoCl2 aqueous solution. By adjusting the concentration of the solution, the compositions can tailored and morphologies of these hydroxides to optimize the OER electrocatalytic performance. Specifically, the CoFe(OH)x-500/NFF electrode manifests as distinctive 3D flower-like clusters composed of remarkably thin nanosheets, measuring a mere 1 nm in thickness. By virtue of the amorphous and ultrathin nanosheet structure, the CoFe(OH)x-500/NFF electrode exhibits superior OER activity, characterized by notably low overpotentials (η100, 274 mV) and an exceptionally small Tafel slope of 40.54 mV dec-1. Moreover, the electrode's performance remains robust, maintaining low overpotentials for 168 h at 100 mA cm-2. In situ Raman spectroscopy indicates that the hydroxides experience surface structural reconstruction and transform into high-valent CoFeO2 with active Co(IV)-O sites during the OER. Theoretical calculations underscore the critical role of the NiFe substrate in enhancing the electrode's OER activity by improving electrical conductivity and modifying the adsorption energy of reaction intermediates, thereby reducing the energy barrier for the reaction.

Regulating the Oxygen Vacancy and Electronic Structure of NiCo Layered Double Hydroxides by Molybdenum Doping for High-Power Hybrid Supercapacitors.

Amelioration of nickel-cobalt layered double hydroxides (NiCo-LDH) with a high specific theoretical capacitance is of great desire for high-power supercapacitors. Herein, a molybdenum (Mo) doping strategy is proposed to improve the charge-storage performance of NiCo-LDH nanosheets growing on carbon cloth (CC) via a rapid microwave process. The regulation of the electronic structure and oxygen vacancy of the LDH is consolidated by the density functional theory (DFT) calculation, which demonstrates that Mo doping narrows the band gap, reduces the formation energy of hydroxyl vacancies, and promotes ionic and charge transfer as well as electrolyte adsorption on the electrode surface. The optimal Mo-doped NiCo-LDH electrode (MoNiCo-LDH-0.05/CC) has an amazing specific capacity of 471.1 mA h g-1 at 1 A g-1 , and excellent capacity retention of 84.8% at 32 A g-1 , far superior to NiCo-LDH/CC (258.3 mA h g-1 and 76.4%). The constructed hybrid supercapacitor delivers an energy density of 103.3 W h kg-1 at a power density of 750 W kg-1 and retains the cycle retention of 85.2% after 5000 cycles. Two assembled devices in series can drive thirty LED lamps, revealing a potential application prospect of the rationally synthesized MoNiCo-LDH/CC as an energy-storage electrode material.

Zn-Leaching Induced Rapid Self-Reconstruction of NiFe-Layered Double Hydroxides for Boosted Oxygen Evolution Reaction.

Optimizing the active centers through reconstruction is recognized as the key to construct high-performance oxygen evolution reaction (OER) catalysts. Herein, a simple and rapid in situ leaching strategy to promote the self-reconstruction of NiFe-layered double hydroxides (LDHs) catalysts is reported. The trace Zn dopants are introduced in advance by a facile and one-step hydrothermal method, followed by leaching over the electrochemical activation process, which can remarkably reduce the formation potential of NiFeOOH active centers to enable the deeper self-reconstruction for the formation of abundant highly active centers. Moreover, the self-restructured NiFeOOH-VZn cannot only significantly lower the dehydrogenation energy barrier for the transformation from Ni(OH)2 to NiOOH, but also decrease the free energy barrier of rate determining step for the *OH converted to *O through a deprotonation process, thus significantly boosting the OER behaviors. As a proof of concept, the obtained NiFeOOH-VZn catalyst just requires a low overpotential of 240 mV at 10 mA cm-2, and delivers robust stability at 50 mA cm-2 over 120 h, which outperforms the benchmark of noble metal RuO2 and those of most non-noble metal catalysts ever reported.

Guided Heterostructure Growth of CoFe LDH on Ti3C2Tx MXene for Durably High Oxygen Evolution Activity.

Heterostructures of layered double hydroxides (LDHs) and MXenes have shown great promise for oxygen evolution reaction (OER) catalysts, owing to their complementary physical properties. Coupling LDHs with MXenes can potentially enhance their conductivity, stability, and OER activity. In this work, a scalable and straightforward in situ guided growth of CoFeLDH on Ti3C2Tx is introduced, where the surface chemistry of Ti3C2Tx dominates the resulting heterostructures, allowing tunable crystal domain sizes of LDHs. Combined simulation results of Monte Carlo and density functional theory (DFT) validate this guided growth mechanism. Through this way, the optimized heterostructures allow the highest OER activity of the overpotential = 301 mV and Tafel slope = 43 mV dec-1 at 10 mA cm-2, and a considerably durable stability of 0.1% decay over 200 h use, remarkably outperforming all reported LDHs-MXenes materials. DFT calculations indicate that the charge transfer in heterostructures can decrease the rate-limiting energy barrier for OER, facilitating OER activity. The combined experimental and theoretical efforts identify the participation role of MXene in heterostructures for OER reactions, providing insights into designing advanced heterostructures for robust OER electrocatalysis.