Nanoflake Arrays Research Articles

Deliberate Amorphization of Co-MOF for Constructing Crystalline-Amorphous Heterostructures Toward High-Performance Water Electrolysis.

The endowment of metal organic frameworks (MOF) with superior electrocatalytic performance without compromising their structural/compositional superiorities is of great significance for the development of renewable energy devices, yet remains a grand challenge. Herein, a deliberate partial amorphization strategy is developed to construct a heterostructured electrocatalyst consisting of crystalline Co-MOF and amorphous Co-S nanoflake arrays aligned on the carbon cloth (CC) substrate (abbreviated as Co-MOF/Co-S@CC hereafter) through a rapid sulfuration method. The simultaneous implement of crystalline-amorphous (c-a) heterostructure and nanoflake arrayed architecture on CC substrate renders the Co-MOF/Co-S@CC with abundant and tight active sites, accelerated charge transfer rate, regulated electronic structures, and reinforced structural stability. As such, the obtained Co-MOF/Co-S@CC electrode demonstrates outstanding electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances with the overpotentials of 64 and 217mV at 10mA cm-2, respectively. Moreover, a two-electrode electrolyzer assembled by Co-MOF/Co-S@CC electrodes exhibits the lower cell voltages and larger current densities than those of Pt/C and RuO2 counterparts, excellent reversibility and prominent long-term stability, representing a great prospect for feasible H2 production. This adopted concept of c-a heterostructure for electronic regulation may bring about insightful inspiration for designing high-performance electrocatalysts for sustainable energy systems.

Binder-free copper manganese sulfide nanoflake arrays electrodeposited on reduced graphene oxide-wrapped nickel foam as an efficient battery-type electrode for asymmetric supercapacitors

In the current study, 2D interconnected copper manganese sulfide (CMS) nanoflake arrays are successfully electrodeposited on nickel foam (NF) and reduced graphene oxide-coated NF (NF/rGO). A pulsed current electrodeposition method is used to prepare a uniform and homogeneous coverage of rGO on NF. By using rGO as a conductive carbon-based template, an ultrathin nanoflake structure of CMS with smaller dimensions and higher electrochemically active surface area (ECSA) is achieved. The results reveal the battery-type behavior of the as-synthesized CMS electroactive materials. At a current density of 5 A g−1 this electrode delivers a significant specific capacity of 667 C g-1 and maintained a considerable proportion of its initial capacity, with a retention value of 83.2 % even after undergoing 3000 charge/discharge cycles. In addition, an asymmetric supercapacitor is fabricated by setting up the synthesized NF/rGO/CMS sample as the positive electrode and activated carbon as the negative electrode. The constructed device not only delivers an impressive energy density of 63.3 Wh kg-1 accompanied by an outstanding power density of 11214.5 W kg−1, but also exhibits a considerable cycling durability, enduring only a 12 % decline in specific capacitance after 3000 charge/discharge cycles at a current density of 5 A g−1.

Amorphous W-doped iron phosphide with superhydrophilic surface to boost water-splitting under large current density

Electrochemical water-splitting is an effective approach for producing hydrogen without producing any pollutants, but its large-scale development is hampered by the lack of low-cost and efficient electrocatalysts. Therefore, it is essential to explore efficient and low-cost non-precious catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, W-doped Fe-P/IF amorphous nanoflake arrays (W-Fe-P/IF) are synthesized by corrosive avenue and following low-temperature phosphorization. Benefiting from the superhydrophilic surface, amorphous structure, nanosheet morphology and abundant active sites, the synthesized catalysts exhibited good catalytic performance. Therefore, the W-Fe-P/IF electrocatalyst onws low overpotentials of 35, 67, and 105 mV to achieve 10 mA cm−2 in 1 M KOH, 1 M KOH + seawater, and 1 M PBS, respectively. In addition, it also exhibits low voltage of 1.63 V to obtain 10 mA cm−2 coupled with excellent stability under 500 mA cm−2. The work provides a new strategy for the preparation of highly-efficient and low-cost non-precious electrocatalysts on renewable energy-related applications.

Flexible Multicavity SERS Substrate Based on Ag Nanoparticle-Decorated Aluminum Hydrous Oxide Nanoflake Array for Highly Sensitive In Situ Detection.

Flexible surface-enhanced Raman scattering (SERS) substrates are very promising to meet the needs for real-time and on-field detection in practical applications. However, high-performance flexible SERS substrates often suffer from complexity and high cost in fabrication, limiting their widespread applications. Herein, we developed a facile method to fabricate a flexible multicavity SERS substrate composed of a silver nanoparticle (AgNP)-decorated aluminum hydrous oxide nanoflake array (NFA) grown on a polydimethylsiloxane (PDMS) membrane. Strong plasmon couplings promoted by multiple nanocavities afford high-density hotspots within such a flexible AgNPs@NFA/PDMS film, boosting high SERS sensitivity with an enhancement factor (EF) of ∼1.54 × 109, and a limit of detection (LOD) of ∼7.4 × 10-13 M for rhodamine 6G (R6G) molecules. Furthermore, benefiting from the high sensitivity, high mechanical stability, and transparency of this substrate, in situ SERS detections of trace thiram and crystal violet (CV) molecules on the surface of cherry tomatoes and fish have been realized, with LODs much lower than the maximum allowable limit in food, demonstrating the great potential of such a flexible substrate in food safety monitoring. More importantly, the preparation processes are very simple and environmentally friendly, and the techniques involved are completely compatible with well-established silicon device technologies. Therefore, large-area fabrication with low cost can be readily realized, enabling the extensive applications of SERS sensors in daily life.

Electrodeposited Cobalt Nanoflake Arrays as an Efficient Anodic Catalyst for Direct Borohydride Fuel Cells

Electrodeposited Cobalt Nanoflake Arrays as an Efficient Anodic Catalyst for Direct Borohydride Fuel Cells

Biphasic Nanoalloys‐Based Trifunctional Monolith for High‐Performance Flexible Zn‐Air Batteries and Self‐Driven Water Splitting

AbstractSufficient integration of multiple active moieties and correlated heterostructure engineering are pivotal to optimize the reaction kinetics and the intrinsic activities of heterogeneous electrocatalysts. Herein, an integrated heterostructure of biphasic nanoalloys are constructed, encasing in in situ grown and interlaced nitrogen‐doped carbon nanoflake arrays (CoFe‐NiFe/NC). Well‐designed CoFe‐NiFe/NC owns more accessible active sites and interfacial conjugation effects, jointly accelerating the electron transfer and mass transport for multifunctional electrocatalysis. Such unconventional monolith delivers extraordinary trifunctional activities for hydrogen evolution reaction, oxygen evolution reaction (overpotential of 185 mV at 10 mA cm−2) and oxygen reduction reaction. The superior trifunctionality of CoFe‐NiFe/NC is rationalized with experimental and theoretical elucidation. Results reveal that the modulated electronic synergism between the Ni, Fe‐assisted Co sites and the adjacent N‐bridged carbon matrix decisively favors the appropriate binding of intermediates for promoted redox kinetics. Consequently, stand‐alone CoFe‐NiFe/NC cathode contributes to high‐performance aqueous/flexible zinc‐air batteries (ZABs), exhibiting high power/specific energy and excellent cycling stability. Remarkably, CoFe‐NiFe/NC‐based alkaline water electrolyzer requires merely 1.51 V to reach 10 mA cm−2, and a self‐driven water splitting system yields a high H2 evolution rate. This unique heterostructure monolith would open up opportunities for developing high‐efficiency multifunctional catalysts and advanced energy utilization devices.

Transforming Undesired Corrosion Products into a Nanoflake-Array Functional Layer: A Gelatin-Assistant Modification Strategy for High Performance Zn Battery Anodes.

As corrosion products of Zn anodes in ZnSO4 electrolytes, Zn4SO4 (OH)6·xH2O with loose structure cannot suppress persistent side reactions but can increase the electrode polarization and induce dendrite growth, hindering the practical applications of Zn metal batteries. In this work, a functional layer is built on the Zn anode by a gelatin-assistant corrosion and low-temperature pyrolysis method. With the assistant of gelatin, undesired corrosion products are converted into a uniform nanoflake array comprising ZnO coated by gelatin-derived carbon on Zn foil (denoted Zn@ZnO@GC). It is revealed that the gelatin-derived carbons not only enhance the electron conductivity, facilitate Zn2+ desolvation, and boost transport/deposition kinetics, but also inhibit the occurrence of hydrogen evolution and corrosion reactions on the zincophilic Zn@ZnO@GC anode. Moreover, the 3D nanoflake array effectively homogenizes the current density and Zn2+ concentration, thus inhibiting the formation of dendrites. The symmetric cells using the Zn@ZnO@GC anodes exhibit superior cycling performance (over 7000h at 1mA cm-2/1 mAh cm-2) and without short-circuiting even up to 25 mAh cm-2. The Zn@ZnO@GC||NaV3O8 full cell works stably for 5000 cycles even with a limited N/P ratio of ≈5.5, showing good application prospects.

High Areal Capacity FeS@Fe Foam Anode with Hierarchical Structure for Alkaline Solid‐State Energy Storage

AbstractThe development of low‐cost and high‐performance iron (Fe)‐based anode materials is of great significance for rechargeable aqueous batteries. Herein, a FeS@Fe foam anode with crosslinked nanoflake array structure is fabricated. Being adopted as alkaline anode, FeS@Fe foam delivers enhanced areal capacity of 31.1 mAh cm−2 (at 50 mA cm−2), which is ≈1.5 times that of the‐state‐of‐the‐art literatures. The scaled‐up tests further reveal the higher capacity (800.7 mAh) and current density (1.25 A) with the area of 25 cm2. The FeS@Fe foam anode sustains intact after 270‐day cycles, demonstrating excellent durability. The assembled FeS//NiO single battery provides a superior areal energy density of 300.7 Wh m−2 at 500 W m−2. The reaction mechanism and electrode kinetics are revealed by combining in/ex situ techniques and DFT calculations. Experimental results and in/ex situ characterizations validate that excellent structural stability and high areal capacity are attributed to effective interface regulation and improved energy storage mechanism, respectively. This work pushes the advanced Fe‐based electrode to a superior level among these available alkaline solid‐state batteries.

Formulation of Hierarchical Nanowire-Structured CoNiO2 and MoS2/CoNiO2 Hybrid Composite Electrodes for Supercapacitor Applications.

Hierarchical porous nanowire-like MoS2/CoNiO2 nanohybrids were synthesized via the hydrothermal process. CoNiO2 nanowires were selected due to the edge site, high surface/volume ratio, and superior electrochemical characteristics as the porous backbone for decoration of layered MoS2 nanoflakes to construct innovative structure hierarchical three-dimensional (3D) porous NWs MoS2/CoNiO2 hybrids with excellent charge accumulation and efficient ion transport capabilities. Physicochemical analyses were conducted on the developed hybrid composite, revealing conclusive evidence that the CoNiO2 nanowires have been securely anchored onto the surface of the MoS2 nanoflake array. The electrochemical results strongly proved the benefit of the hierarchical 3D porous MoS2/CoNiO2 hybrid structure for the charge storage kinetics. The synergistic characteristics arising from the MoS2/CoNiO2 composite yielded a notably high specific capacitance of 1340 F/g at a current density of 0.5 A/g. Furthermore, the material exhibited sustained cycling stability, retaining 95.6% of its initial capacitance after 10 000 long cycles. The asymmetric device comprising porous MoS2/CoNiO2//activated carbon encompassed outstanding energy density (93.02 Wh/kg at 0.85 kW/kg) and cycling stability (94.1% capacitance retention after 10 000 cycles). Additionally, the successful illumination of light-emitting diodes underscores the significant potential of the synthesized MoS2/CoNiO2 (2D/1D) hybrid for practical high-energy storage applications.

A 2.4 V Aqueous Zinc-Ion Battery Enabled by the Photoelectrochemical Effect of a Modified BiOI Photocathode: Shattering the Shackle of the Electrochemical Window of an Aqueous Electrolyte.

Aqueous zinc-ion batteries emerge as a promising energy storage system with merits of high security, abundance, and being environmentally benign. But the low operating voltages of aqueous electrolytes restrict their energy densities. Previous reports have mostly focused on modifying the electrolytes to enlarge the operating voltages of aqueous zinc-ion batteries. However, either extra-expensive salts or potential safety hazards of organic additives are considered to be adverse for practical large-scale applications. Here, a proof-of-concept to enlarge the operating voltage of an aqueous zinc-ion battery by incorporating a well-designed semiconductor photocathode is proposed, which produces a photovoltage (Vph) across the semiconductor/liquid junction (SCLJ) interface to elevate the output voltage of zinc-ion battery under irradiation. The operating voltage of an aqueous zinc-ion battery can be markedly raised from 1.78 (thermodynamic limit) to 2.4 V when a BiOI nanoflake array photocathode with good surface modification is introduced, achieving a round-trip efficiency of 114.3% and a 34.8% increase of energy density compared to the theoretical value. The successive ionic layer adsorption and reaction modified surface effectively passivates surface trap defects of the BiOI photocathode and thus enlarges its Vph from 60 to 240 mV under irradiation. This study provides a design to enlarge the output voltages of aqueous zinc-ion batteries and other energy storage systems, providing insight into widening the voltage window, which is that the operating voltages are determined by photocathode under irradiation and not restricted by the electrochemical stability window of dilute aqueous electrolytes.

Large scale and oxygen vacancy VO2 porous thin sheets to enable high-performance zinc ion storage.

Herein, we report the first result of large scale and oxygen vacancy VO2 porous thin sheets assembled by a 3D interconnected nanoflake array framework, which is recorded as VOd. The as-prepared VOd was characterized by various methods and Zn2+ intercalation/deintercalation and structural decomposition mechanisms were proposed based on ex situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).

Fabrication of bimetallic Co/Ni composite oxides on Ni-foam as a highly active monolithic membrane catalyst for the reduction of 4-nitrophenol

The development of highly active non-noble metal catalysts is the prerequisite for the practical application of the reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) by NaBH4. In this work, inexpensive Co/Ni bimetallic composite oxide integral membrane catalysts with different metal-ion molar ratios towards 4-NP reduction were grown on the nickel foam (NF) substrate by a facile oxalate-pyrolysis method. Benefiting from the synergistic effect between Co and Ni elements, special crystalline phase of NiCo2O4 with high electron transfer capacity and uniform nanoflake array structure, the NF-based monolithic membrane catalyst with a Co/Ni molar ratio of 2:1 (Co2Ni1) exhibited the optimal activity for the catalytic reduction of 4-NP. A reduction ratio of 96.71% for 250 mL of 4-NP with an initial concentration of 15 mg/L could be reached within 25 min under the reaction conditions as follows: two pieces of Co2Ni1 catalytic membranes (20 × 40 mm2), 0.015 mol/L NaBH4 and a temperature of 25 °C. The corresponding kinetic reaction rate constant was 0.1410 min−1, which was 2.0 and 15.5 times higher than that of pure Co3O4 and NiO. Moreover, the activation energy, enthalpy and entropy for the reaction were calculated as 17.44 kJ/mol, 14.97 kJ/mol and −210.61 J•mol−1•K−1, respectively. Notably, the reduction rates of 4-NP remained at around 97% during thirteen consecutive catalytic runs, indicating the good reusability of the Co2Ni1 integral membrane catalyst. These results show that NF-based Co/Ni composite oxide membrane is a promising integral catalyst for converting of 4-NP into 4-AP owing to its excellent properties and easy recovery feature.

The improvement of photocatalytic activity of BiVO4 modified with Co(OH)2 nanoflake arrays for photocatalytic and photo-electrocatalytic desulfurization

Various and economical pure BiVO4 and Co(OH)2 nanoflake deposited BiVO4 photocatalysts have been prepared using the electrodeposition technique. Improved photocurrent density of 64 µA/cm2 at 1.0 V vs. Ag/AgCl was shown by Co(OH)2-BiVO4-150 photoanode (BiVO4 after 150 s of cobalt electrodeposition), which is about 8 times higher compared with BiVO4 photoanode. The catalysts prepared have also been used in the photocatalytic oxidation of dibenzothiophene (DBT), which is applied to stimulate fluid catalytic cracking for gasoline production in n-heptane solution. The corresponding parameters in the optimization of oxidative desulfurization of DBT were reaction time, temperature, solvent, DBT concentration and electrical bias voltage. The highest DBT desulfurization efficiency was shown by Co(OH)2-BiVO4-150. Based on the mechanism of photocatalytic oxidation, the superoxide and hydroxyl radicals played major parts in DBT degradation. Co(OH)2-BiVO4-150 photoanode showed better photo-electrocatalytic degradation efficiency, reaching a high 78.3% DBT removal even during the reaction time, in comparison with photocatalysis and electrocatalysis. The photocatalytic degradation system containing Co(OH)2-BiVO4-150 may be recycled six times without any important reduction of photocatalytic activity. This procedure introduces a simple and sustainable approach for the modification of BiVO4 to improve its photoelectrochemical and photocatalytic activity.

ZIF‐Derived Co3O4 Nanoflake Arrays Decorated Nickel Foams as Stable Hosts for Dendrite‐Free Li Metal Anodes

Developing high‐performance anode current collectors with three‐dimensional structure and lithiophilic layers is of great importance to further advance the application of lithium metal batteries. However, relatively few research has focused on the transition of substrate and the intrinsic structure stability after electrodeposition of lithium on substrates, which leads to an incomplete understanding of the behavior of lithium deposition. Herein, a lithium metal anodes host with a highly stable and 3D structure has been effectively produced through in situ development of nanoflake arrays embedded with Co3O4 obtained from ZIF on nickel foams (Co3O4‐NF). And the actual lithium deposition sites and lithium deposition process on Co3O4‐NF are elucidated via a combination of characterization techniques and electrochemical analytical methods. Consequently, the resulting Co3O4‐NF@Li anodes could effectively inhibit lithium dendrite formation and mitigate volume expansion, demonstrating a significantly extended and consistent lifespan of 800 cycles (1600 h) at 1 mA cm−2 with low overpotential and insignificant voltage fluctuation for the process of lithium stripping and plating in symmetric cells. Herein, it is aimed to examine the transitions of metal oxides as a lithiophilic site for the lithium metal anode. It offers novel perspectives and approaches for the design of dendrite‐free lithium metal anodes.

An ultra-sensitive electrochemical sensing platform based on nanoflower-like Au/ZnO array on carbon cloth for the rapid detection of the nitrite residues in food samples

In this work, we constructed an enhanced electrochemical signal sensing platform using Au/ZnO nanoflake arrays coated on carbon cloth for the rapid detection of nitrite in food. Based on a stepwise synthesis strategy of electrodeposition and magnetron sputtering technique, AuNPs were sputtered onto ZnO nanoflower-like array sheets. Combining the high catalytic performance of AuNPs with the morphology of ZnO significantly increased the surface area and electrocatalytic activity of the electrodes. The prepared sensor showed a linear response range of 0.2–4986 μΜ, a limit of detection of 0.09 μM, and a high sensitivity of 5677 μA mM−1 cm−2. It is worth noting that the sensor can precisely detect nitrite in the presence of interfering substances and has excellent stability and reproducibility. In addition, the nitrite residues in several food samples were analyzed using this method and spectrophotometric method, and the results of the two methods were not significantly different.

Anchoring Polar Organic Molecules in Defective Ammonium Vanadate for High-Performance Flexible Aqueous Zinc-Ion Battery.

Ammonium vanadate (NVO) often has unsatisfactory electrochemical performance due to the irreversible removal of NH4 + during the reaction. Herein, layered DMF-NVO nanoflake arrays (NFAs) grown on highly conductive carbon cloth (CC) are employed as the binder-free cathode (DMF-NVO NFAs/CC), which produces an enlarged interlayer spacing of 12.6Å (against 9.5 Å for NH4 V4 O10 ) by effective N, N-dimethylformamide (DMF) intercalation. Furthermore, the strong attraction of highly polar carbonyl and ammonium ions in DMF can stabilize the lattice structure, and low-polar alkyl groups can interact with the weak electrostatic generated by Zn2+ , which allows Zn2+ to be freely intercalated. The DMF-NVO NFAs/CC//Zn battery exhibits an impressive high capacity of 536 mAh g-1 at 0.5Ag-1 , excellent rate capability, and cycling performance. The results of density functional theory simulation demonstrate that the intercalation of DMF can significantly reduce the band gap and the diffusion barrier of Zn2+ , and can also accommodate more Zn2+ . The assembled flexible aqueous rechargeable zinc ion batteries (FARZIBs) exhibit outstanding energy density and power density, up to 436Wh kg-1 at 400W kg-1 , and still remains 180Wh kg-1 at 4000W kg-1 . This work can provide a reference for the design of cathode materials for high-performance FARZIBs.

Promoting High-Oxidation-State Metal Active Sites in a Hollow Ternary Metal Fluoride Nanoflake Array for Urea Electrolysis.

The adsorption ability of hydrogen, hydroxide, and oxygenic intermediates plays a crucial role in electrochemical water splitting. Electron-deficient metal-active sites can prompt electrocatalytic activity by improving the adsorption ability of intermediates. However, it remains a significant challenge to synthesize highly abundant and stable electron-deficient metal-active site electrocatalysts. Herein, we present a general approach to synthesizing a hollow ternary metal fluoride (FeCoNiF2) nanoflake array as an efficient and robust bifunctional electrocatalyst for the hydrogen evolution reaction (HER) and urea oxidation reaction (UOR). We find that the F anion withdraws electrons from the metal centers, inducing an electron-deficient metal center catalyst. The rationally designed hollow nanoflake array exhibits the overpotential of 30 mV for HER and 130 mV for UOR at a current density of 10 mA cm-2 and superior stability without decay events over 150 h at a large current density of up to 100 mA cm-2. Remarkably, the assembled urea electrolyzer using a bifunctional hollow FeCoNiF2 nanoflake array catalyst requires cell voltages of only 1.352 and 1.703 V to afford current densities of 10 and 100 mA cm-2, respectively, which are 116 mV less compared with that required for overall water splitting.

In Situ Construction of Heterostructured Co3O4/CoP Nanoflake Arrays on Carbon Cloth as Binder-Free Anode for High-Performance Lithium-Ion Batteries

Cobalt oxide (Co3O4) is regarded as the anode material for lithium-ion batteries (LIBs) with great research value owing to its environmental friendliness and exceptional theoretical capacity. However, the low intrinsic conductivity, poor electrochemical kinetics, and unsatisfactory cycling performance severely limit its practical applications in LIBs. The construction of a self-standing electrode with heterostructure by introducing a highly conductive cobalt-based compound is an effective strategy to solve the above issues. Herein, Co3O4/CoP nanoflake arrays (NFAs) with heterostructure are constructed skillfully directly grown on carbon cloth (CC) by in situ phosphorization as an anode for LIBs. Density functional theory simulation results demonstrate that the construction of heterostructure greatly increases the electronic conductivity and Li ion adsorption energy. The Co3O4/CoP NFAs/CC exhibited an extraordinary capacity (1490.7 mA h g-l at 0.1 A g-l) and excellent performance at high current density (769.1 mA h g-l at 2.0 A g-l), as well as remarkable cyclic stability (451.3 mA h g-l after 300 cycles with a 58.7% capacity retention rate). The reasonable construction of heterostructure can promote the interfacial ion transport, significantly enhance the adsorption energy of lithium ions, improve the conductivity of Co3O4 electrode material, promote the partial charge transfer throughout the charge and discharge cycles, and enhance the overall electrochemical performance of the material.

Synergetic Nanostructure Engineering and Electronic Modulation of a 3D Hollow Heterostructured NiCo2O4@NiFe-LDH Self-Supporting Electrode for Rechargeable Zn–Air Batteries

Developing electrocatalysts that integrate the merits of the hollow structure and heterojunction is an attractive but still challenging strategy for addressing the sluggish kinetics of oxygen evolution reaction (OER) in many renewable energy technologies. Herein, a 3D hierarchically flexible self-supporting electrode with a hollow heterostructure is intentionally constructed by assembling thin NiFe layered double hydroxide (LDH) nanosheets on the surface of metal-organic framework-derived hollow NiCo2O4 nanoflake arrays (NiCo2O4@NiFe-LDH) for rechargeable Zn-air batteries (ZABs). Theoretical calculations demonstrate that the interfacial electron transfer from NiFe-LDH to NiCo2O4 induces the electronic modulation, improves the conductivity, and lowers the reaction energy barriers during OER, ensuring high catalytic activity. Meanwhile, the 3D hierarchically hollow nanoarray architecture can afford plentiful catalytic active sites and short mass-/charge-transfer pathways. As a result, the obtained catalyst exhibits remarkable OER electrocatalytic performance, showing low overpotentials (only 231 mV at 10 mA cm-2, 300 mV at 50 mA cm-2) and robust stability. When assembling liquid and flexible solid-state ZABs with NiCo2O4@NiFe-LDH as the OER catalyst, the ZABs achieve excellent power density, high specific capacity, superior cycle durability, and good bending flexibility, exceeding the RuO2 + Pt/C benchmarks and other previously reported self-supporting catalysts. This work not only constructs an advanced hollow heterostructured catalyst for sustainable energy systems and wearable electronic devices but also provides insights into the role of interfacial electron modulation in catalytic performance enhancement.

Controlling crystallinity of oxygen-deficient tungsten oxide on SnO2 nanoflake arrays for advanced dual-band electrochromic smart window

Controlling crystallinity of oxygen-deficient tungsten oxide on SnO2 nanoflake arrays for advanced dual-band electrochromic smart window