Hierarchical Nanoarchitectures Research Articles

Ultra-stable electrocatalysts for overall urea degradation by NiFeCoZn-S modified N-doped carbon

Urea degradation is a viable method to produce hydrogen in a sustainable way, while having an important place in environmental protection and energy security. In this work, ultrathin N-doped carbon (NC) nanosheets, modified by ultrafine multiple transition metal sulfide (NiFeCoZn-S) nanoparticles, are synthesized to serve as electrocatalysts for overall urea degradation. This unique structure allows NiFeCoZn-S/NC to have a relatively large ECSA and active sites, stemming from the small dimensions of the NiFeCoZn-S particles and the hierarchical nanoarchitecture of the NC. Thus, NiFeCoZn-S/NC has a significant urea oxidation reaction (UOR) activity of 1.31 V at 10 mA cm-2 in an electrolyte consisting of 1.0 M KOH and 0.33 M urea. Furthermore, when the catalyst was used in an electrolytic cell for urea degradation, a potential of 1.49 V was achieved up to 10 mA cm-2. Additionally, the catalyst exhibits only a 6.1% performance decay after 660 h of operation at 10 mA cm-2. Its exceptional stability outshines that of existing urea catalysts, rendering it an attractive prospect for future applications.

Multiple strategies regulating the d-band center of Ni2P/NiFe2O4 @N-GTs hierarchical nanoarchitecture as efficient electrocatalyst for overall water splitting

The rational design of highly active electrocatalysts for water electrolysis remains challenging for green hydrogen utilization. Herein, guided by the correlation between the electroactivity and the d-band center (Ed), a novel hierarchical nanoarchitecture (Ni2P/NiFe2O4-VO@N-GTs) was fabricated, in which, Ni2P nanoparticles are grown on the oxygen vacancy-rich NiFe2O4 nanosheet arrays anchoring on N-doping graphene tubes. The results reveal that the multiple strategies including the vacancies and heterogeneous interface construction effectively induce the charge redistribution, and further adjust the Ed to the appropriate energy level, which endows the optimal balance between the adsorption and desorption ability of the catalyst to reaction intermediates, thus leading to the conspicuous electrocatalytic activity. Additionally, the hierarchical nanoarchitecture contributes to the exposure of more active sites, the efficiency of electron transfer, and the release of generated gas. Hence, Ni2P/NiFe2O4-VO@N-GTs presents superior bifunctional activity, especially a low overpotential of 194 mV at 10 mA cm−2 for OER. The corresponding overall water electrolyzer owns a lower cell voltage and long-term durability with continuously operating over 330 h at 100 mA cm−2, outperforming the most reported bifunctional electrocatalysts. This work presents an effective pathway for regulating the Ed through multiple strategies to improve the catalytic performance of catalysts.

In situ fabrication of Ag nanoparticles modified vertically-grown ZnO nanorods on carbon fiber paper electrode for simultaneous detection of luteolin, daidzein and baicalein

In this paper, a facial strategy is employed to directly growing ZnO nanorods (ZnONR) on carbon fiber paper (CFP) and functionalizing with silver nanoparticles (AgNP), constructing a structural stable paper-based electrode (AgNP/ZnONR@CFP). This unique AgNP/ZnONR hierarchical nanoarchitecture provides large surface area and an easy substrate penetrable structure facilitating enhanced electrochemical features towards flavonoids oxidation. When the electrode is evaluated as a binder-free sensor for flavonoids detection, three distinct and separate differential pulse voltammetric peaks for luteolin, daidzein, and baicalein are observed, demonstrating the simultaneous and selective detection of these flavonoids possible. The AgNP/ZnONR@CFP sensor demonstrates a remarkable wide linear relationship with low detection limits for luteolin, daidzein, and baicalein detection in a mixed solution. When the sensor is employed to analyze luteolin, daidzein, or baicalein in real extracts from Japanese Honeysuckle, Soybean, and Chrysanthemum morifolium, satisfactory recovery rates (ranging from 96.3 % to 102.5 %) and low relative standard deviation (RSD) values (less than 5.0 %) are obtained. In addition, an assembled sensor device (two-electrode) based on this trimmable AgNP/ZnONR@CFP electrode exhibits remarkable quick response and excellent sensitivity for luteolin, daidzein, or baicalein detection, facilitating real-time and portable detection, highlighting its great potential in batch production of the sensor devices.

Flower-like CoSe2/N, P-doped carbon microspheres accommodated on carbon nanosheets for high-performance potassium-ion batteries

Transition metal selenides (TMSs) have emerged as promising electrode materials for potassium-ion batteries (PIBs), whereas the large volume expansion and sluggish reaction kinetics have seriously hindered the cycle life and rate performance. Herein, a hierarchical composite of flower-like CoSe2/N, P-doped carbon microspheres accommodated on carbon nanosheets (CoSe2-NPC@CNS) was rationally fabricated as the anode for PIBs through a one-pot hydrothermal and subsequent selenization method. The intimate hybridization of CoSe2/N, P-doped carbon microspheres can effectively alleviate the volume expansion of CoSe2 during charge-discharge cycles, and the ultrathin carbon nanosheets derived from fluid catalytic cracking (FCC) slurry serves as a highly conductive and buffered substrate. By robustly merging them together, the interconnected hierarchical nanoarchitecture with exposed active sites achieves promoted potassium storage capacity, electrochemical reaction kinetics, and structural stability. As a result, the PIBs with CoSe2-NPC@CNS anode deliver high reversible capacities of 320.8 mAh g−1 after 100 cycles at 0.1 A g−1 and 213.9 mAh g−1 after 850 cycles at 1.0 A g−1, excellent rate capability (188.8 mAh g−1 at 5 A g−1), and enhanced pseudo-capacitive contribution rate of 88.7 %. This work offers valuable insight into the rational design and development of hierarchical anode materials with high performance for PIBs and beyond.

3D hierarchical porous N-doped carbon nanoarchitecture coated bimetallic phosphides as a highly efficient bifunctional electrocatalyst for overall water splitting

As the energy and ecological crises are increasingly grim, it is challengeable but extremely attractive to fabricate highly efficient and low-cost bifunctional electrocatalysts for overall water splitting (OWS). Herein, a bimetallic phosphide embedded in N-doped hierarchical porous carbon (CoP/Ni2P@NHPC) framework was successfully constructed by calcination and phosphorization of cobalt–nickel coordination polymer nanoflowers (Co/Ni CPNFs), which were obtained by a facile hydrothermal process. Benefitting from their fascinating architecture and composition, the as-prepared CoP/Ni2P@NHPC exhibits outstanding electrochemical properties for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with small Tafel slopes (103.9 mV dec-1, 62.58 mV dec-1) and ultralow overpotentials (275 mV, 159 mV at 10 mA cm−2) in alkaline medium. Additionally, the CoP/Ni2P@NHPC can be used as a bifunctional catalyst in a two-electrode water splitting device, and it only requires a low cell voltage of 1.55 V to attain the current density of 10 mA cm−2. Meanwhile, the CoP/Ni2P@NHPC also present admirable durability (at least 20 h) under long-term electrolysis. This work gives inspiration for the preparation of highly active bifunctional electrocatalysts for OWS.

Hydrothermal synthesis and photocatalytic application of ZnS-Ag composites based on biomass-derived carbon aerogel for the visible light degradation of methylene blue.

A facile and cost-effective hydrothermal followed by precipitation method is employed to synthesize visible light-driven ZnS-Ag ternary composites supported on carbon aerogel (CA). Extensive studies were conducted on the structural, morphological, and optical properties, confirming the successful formation of ternary nanocomposites. The obtained results evidently demonstrate the successful loading of ZnS and Ag onto the surface of the CA. High-resolution transmission electron microscopy analysis revealed that ZnS and Ag nanoparticles (AgNPs) were uniformly distributed on the surface of the CA with an average diameter of 18nm. The biomass-derived CA, containing a hierarchical porous nano-architecture and an abundant number of -NH2 functional groups on the surface, can greatly prevent the agglomeration, stability and reduce particle size. Brunauer-Emmett-Teller analysis results indicated specific surface areas of 4.62m2g-1 for the CA, 48.50m2g-1 for the CA/ZnS composite, and 62.62m2g-1 for the CA/ZnS-Ag composite. These values demonstrate an increase in surface area upon the incorporation of ZnS and Ag into the CA matrix. Under visible light irradiation, the synthesized CA/ZnS-Ag composites displayed remarkably improved photodegradation efficiency of methylene blue (MB). Among the tested samples, the CA/ZnS-Ag composites exhibited the highest percentage of photodegradation efficiency, surpassing ZnS, CA, and CA/ZnS. The obtained percentages of degradation efficiency for CA, ZnS, CA/ZnS, and CA/ZnS-Ag composites were determined as 26.60%, 52.12%, 68.39%, and 98.64%, respectively. These results highlight the superior photocatalytic performance of the CA/ZnS-Ag composites in the degradation of MB under visible light conditions. The superior efficiency of the CA/ZnS-Ag composite can be attributed to multiple factors, including its elevated specific surface area, inhibition of electron-hole pair recombination, and enhanced photon absorption within the visible light spectrum. The CA/ZnS-Ag composites displayed consistent efficiency over multiple cycles, confirming their stable performance, reusability, and enduring durability, thereby showcasing the robust nature of this composite material.

Preparation of ZnO hierarchical nanoarchitectures and their photocatalytic performance

ZnO HNAs were prepared via a simple hydrothermal process. The samples were characterized via different techniques. The effect of temperature on the morphology, structure and properties of ZnO samples was investigated. The obtained ZnO HNA samples exhibited an impressive photocatalytic performance and good separation-recycling performance due to the porous structures assembled by nanosheets and large secondary particle size.

A facile dual-template-directed successive assembly approach to hollow multi-shell mesoporous metal–organic framework particles

Hollow multi-shell mesoporous metal–organic framework (MOF) particles with accessible compartmentalization environments, plentiful heterogeneous interfaces, and abundant framework diversity are expected to hold great potential for catalysis, energy conversion, and biotechnology. However, their synthetic methodology has not yet been established. In this work, a facile dual-template-directed successive assembly approach has been developed for the preparation of monodisperse hollow multi-shell mesoporous MOF (UiO-66-NH2) particles through one-step selective etching of successively grown multi-layer MOFs with alternating two types of mesostructured layers. This strategy enables the preparation of hollow multi-shell mesoporous UiO-66-NH2 nanostructures with controllable shell numbers, accessible mesochannels, large pore volume, tunable shell thickness and chamber sizes. The methodology relies on creating multiple alternating layers of two different mesostructured MOFs via dual-template-directed successive assembly and their difference in framework stability upon chemical etching. Benefiting from the highly accessible Lewis acidic sites and the accumulation of reactants within the multi-compartment architecture, the resultant hollow multi-shell mesoporous UiO-66-NH2 particles exhibit enhanced catalytic activity for CO2 cycloaddition reaction. The dual-template-directed successive assembly strategy paves the way toward the rational construction of elaborate hierarchical MOF nanoarchitectures with specific physical and chemical features for different applications.

Sulfur vacancies reinforced cobalt molybdenum sulfide nanosheets integrated cathode for high energy density hybrid supercapacitors

Rational design and construction of bimetallic sulfide materials integrated cathode with well-defined hierarchical nanoarchitectures plays a vital role in boosting the electrochemical performance of hybrid supercapacitors (HSCs). Herein, sulfur vacancies reinforced cobalt molybdenum sulfide nanosheets (Vs-CMS) integrated cathodes are prepared by hydrothermal and NaBH4 reduction methods. The introduction of sulfur vacancies in CMS not only contributes to more active sites for faradic redox reactions but also accelerates electron and ion transmission. Benefiting from the synergistic effects of well-defined hierarchical nanoarchitecture and sulfur vacancies, the optimal Vs-CMS integrated cathode delivers a high areal capacity of 0.56 mAh cm−2 at 1 mA cm−2, good rate performance of 0.34 mAh cm−2 at 30 mA cm−2, and excellent cycling stability with 96.7% capacity retention after 10,000 cycles. Furthermore, capacitive-type porous framework activated carbon (PFAC) anodes are used to couple with the optimal Vs-CMS cathodes for assembling HSCs. The as-obtained PFAC anodes possess a high specific capacitance of 112.1 F g− 1 at 0.25 A g− 1, high rate capability of 46.3 F g− 1 at 10 A g− 1, and good cycling stability of 95.5% capacitance retention after 10,000 cycles. The as-assembled HSCs deliver maximum energy density of 73.2 Wh kg−1 and power density of 3014.7 W kg−1, and prominent cyclic stability of 93.3% capacity retention after 10,000 cycles.

Design and synthesis of hierarchical MnO–Fe3O4@C/expanded graphite composite for sensitive electrochemical detection of bisphenol A

Hierarchically nanostructured binary transition metal oxide-based materials with high conductivity and catalytic activity are quite attractive for the electrochemical quantitative detection of environmental pollutants due to their natural abundance, variable oxidation state, and excellent synergies between metal sites. Herein, a new hierarchical MnO–Fe3O4@C/expanded graphite (EG) composite is designed and synthesized through a simple and in situ annealing method with the utilization of bimetallic organic framework (FeMn-MOF)/EG precursor. The synthesized MnO–Fe3O4@C/EG composite possesses a unique hierarchical nanoarchitecture that small-sized bimetallic oxide nanoparticles of 10–40 nm completely encapsulated by amorphous carbon layers of 2–4 nm are uniformly distributed on the EG platform. This distinctive structure combines the advantages of high conductivity, excellent catalytic activity, and strong stability. Resultantly, when it is applied to monitor environmental endocrine disruptors, the sensor exhibits a significant catalytic effect on the electrochemical oxidation of bisphenol A (BPA), inducing an amplified response current. In addition, the sensor shows a wide linear range of 1–50 μM and 50–400 μM for the BPA monitor, giving a sensitivity of 5208.8 and 1641.9 μA mM−1 cm−2, respectively. This study offers a new approach to design hierarchical binary metal oxide-based sensing materials as well as to explore their electrochemical properties and applications for the determination of emerging contaminants.

Amorphous and crystalline interface engineering of FeSeOx/Mo-NiSe2 nanoarrays for synergistically boosting electrocatalytic water oxidation

Exploring integrated regulation strategies to boosting electrocatalytic performance is essential to design more efficient and inexpensive OER catalysts. Herein, amorphous and crystalline (a-c) interface engineering and heteroatom doping are integrated to construct a novel electrocatalyst containing amorphous FeSeOx and crystalline Mo-doped NiSe2 (denoted as FeSeOx/Mo-NiSe2) via pseudocrystalline replication method and selenization treatment. The resultant FeSeOx/Mo-NiSe2 electrocatalyst with 3D hierarchical nanoarchitectures of nanorod arrays covered by interlocking nanoblocks exposes more active sites and accelerated reaction kinetics. Furthermore, a-c interface engineering and heteroatom doping can synergistically enhance the intrinsic activity and charge transfer capability of NiSe2 by decreasing the electron diffusion distance and flexibly modulating the electronic structure, which contributes to boost the oxygen evolution reaction (OER) performance. Consequently, the obtained FeSeOx/Mo-NiSe2 achieves a low overpotential of 205 mV at 10 mA cm−2, which outperforms many other transitions metal selenides electrocatalysts. Density functional theory (DFT) calculations demonstrate that the formation of an internal electric field between FeSeOx and Mo-NiSe2 accelerates charge transport and optimizes the adsorption/desorption of oxygen-containing intermediates, thereby accelerating the reaction kinetics and improving the OER performance. This work serves as a point of reference for designing innovative metal selenides based electrocatalysts combining a-c interface engineering and heteroatom doping.

Hierarchical nanoarchitecture with NiFe-LDH on MoS2 for enhanced electrocatalysis of hydrogen evolution in alkaline media

Molybdenum disulfide (MoS2) can effectively improve the efficiency of hydrogen evolution reaction (HER) and reduce the cost of hydrogen production. However, MoS2 is kinetically sluggish in alkaline media, which makes it difficult to apply directly to HER. In order to improve the applicability of MoS2 in HER, this paper designs a hierarchical NiFe-LDH/MoS2 nanosheet with a heterogeneous interface anchored on carbon fiber paper (CFP) to optimize the performance of MoS2. The experimental results show that the NiFe-LDH/MoS2/CFP electrode in 1.0 M KOH exhibits excellent HER activity with only 88.5 mV overpotential at 10 mA cm−2. The good performance is attributed to numerous active sites on the NiFe-LDH/MoS2 heterogeneous surface, the good electrical conductivity of MoS2 and CFP, as well as the pores distributed on NiFe-LDH/MoS2 that facilitate mass transfer. It is also found that the catalyst exhibits outstanding stability (24 h) in alkaline media. This work opens up new prospects for the development of high-performance electrocatalysts in alkaline media.

Self-assembled hierarchical porous nanoarchitectured 2,6-diaminopyridine decorated N-doped reduced graphene oxide as advanced electrode for high-performance aqueous Zn-ion hybrid supercapacitors

2,6-diaminopyridine (DAP), an active organic molecule containing amino groups and pyridine N is expected to be an attractive material for energy storage due to its fast and reversible proton-involved redox activity. Herein, the novel N-doped (or CNTs) and DAP organic molecules double-modified reduced graphene oxide nanocomposites with hierarchical porous nanoarchitectures were successfully designed and synthesized by a simple solvothermal method. Benefiting from the advantages of the three components and the positive synergistic enhancement between them, the newly synthesized N-RGO/DAP and CNTs/RGO/DAP nanocomposites exhibit excellent electrochemical properties, such as high specific capacitance, excellent rate capability and cycling stability. Furthermore, the Zn-ion hybrid supercapacitor further assembled with the optimal N-RGO/DAP as cathode delivers excellent Zn-ion energy storage performance in aqueous electrolyte, with a high specific capacitance (capacity) of 320.2 F g−1 (158.3 mAh g−1), excellent energy density of 140.9 Wh kg−1 at a power density of 534 W kg−1, and an ultra-long durability of 95.3% capacitance retention after 16,000 cycles at a large current of 100 mV s−1. This paper provides a novel strategy and advanced electrode nanocomposite with excellent electrochemical properties, which shows great promise in high-performance energy storage devices with high-flexibility, light-weight and sustainability.

Comparison study of WO3 thin film and nanorods for smart window applications

The WO3 thin films were deposited at oxygen partial pressure of 8x10-4 mbar. A template-free straightforward hydrothermal method is employed to produce vertical alignment hierarchical WO3 nano-architectures on clear conducting substrates (3x2.5 cm2 in size and slides resistance 4 O). After being deposited at ambient temperature, the samples were air annealed at 400 °C for 4 h. The optical, electrochromic, surface and structural morphology behavior of the deposited material after annealing were studied using XRD, Raman, FTIR, SEM, electrochemical analyzer and UV–Visible spectrometer characterization methods. After annealing at 400 °C for 4 h in air, every characteristic peak are matched to a monoclinic (crystalline) WO3 phase. The Nano flower array achieved a considerable coloration efficiency (24.09 cm2/s) and low cathodic peak current (−2.03 mA) compare to the Tungsten trioxide thin film produced by the DC magnetron sputtering method. The vertically oriented geometry and the porosity space between the Nano flower, which improve H+ diffusion and provide a considerable contact area for charge-transfer processes, are primarily responsible for the improved electrochromic properties.

Thin Films Fabricated by Pulsed Laser Deposition for Electrocatalysis

Thin Films Fabricated by Pulsed Laser Deposition for Electrocatalysis

Constructing N-doped and 3D Hierarchical Porous graphene nanofoam by plasma activation for supercapacitor and Zn ion capacitor

Traditional electrode materials still face vital challenges of few active sites, low porosity, complex synthesis process, and low specific capacitance. Herein, N-doped and 3D hierarchical porous graphene nanofoam (N-GNF) is created on carbon fibers (CFs) by employing a facile, fast, and environmentally friendly strategy of N2 plasma activation. After an appropriated N2 plasma activation, the graphene nanosheets (GNSs) synthesized by Ar/CH4 plasma deposition transform into N-GNF successfully. N doping donates rich active sites and increases the hydrophilia, while hierarchical nanoarchitecture exposes an enlarged effective contact area at the interface between electrode and electrolyte and affords sufficient space for accommodating more electrolytes. The as-assembled flexible N-GNF@CFs//Zn NSs@CFs Zn ion capacitor delivered a high energy density of 105.2 Wh kg-1 at 378.6W kg-1 and initial capacity retention of 87.9% at the current of 2Ag-1 after a long cycle of 10,000.

Hierarchical Fe3O4@LDH-incorporated composite anion exchange membranes for fuel cells based on magnetic field orientation

The trade-off between ionic conductivity and mechanical properties is the key issue facing anion exchange membranes (AEMs) at present. Herein, a new strategy combing three-dimensional (3D) hierarchical nanoarchitecture and magnetic field orientation was proposed to prepare imidazolium-functionalized poly(2,6-dimethyl phenylene oxide) (ImPPO)-based composite AEMs with simultaneously improved ionic conductivity and mechanical strength. Magnetic Fe3O4@LDH microspheres using Fe3O4 as the core and two-dimensional lamellar anion conductor, layered double hydroxide (LDH), as the shell were prepared through a simple co-precipitation method. The as-prepared Fe3O4@LDH was then incorporated into ImPPO matrix and induced by an external magnetic field to fabricate Fe3O4@LDH-orientated composite AEMs. The hierarchical-structured Fe3O4@LDH can not only effectively avoid the stacking of LDH laminates and thus fully play the ion conduction ability of LDH, but also contribute to the formation of continuous OH− ion transport pathway in the composite system after magnetic field induction. The magnetic-field-oriented membrane with 1% Fe3O4@LDH doping exhibited ionic conductivity of 128.9 mS cm−1 at 80 °C, which was 43.1% higher than that of pure ImPPO. Moreover, the high dry strength (30.7 MPa) and satisfactory wet strength and flexibility of the composite membrane were also obtained. The assembled direct methanol fuel cell demonstrated a peak power density of 11.7 mW cm−2, and showed an OCV retention of as high as 94.7% after continuous operation for 100 h, indicating their great potential for fuel cell applications.

Metal Organic Framework‐MXene Nanoarchitecture for Fast Responsive and Ultra‐Stable Electro‐Ionic Artificial Muscles

AbstractElectro‐ionic soft actuators, capable of continuous deformations replacing non‐compliant rigid mechanical components, attract increasing interest in the field of next‐generation metaverse interfaces and soft robotics. Here, a novel MXene (Ti3C2Tx) electrode anchoring manganese‐based 1,3,5‐benzenetricarboxylate metal‐organic framework (MnBTC) for ultrastable electro‐ionic artificial muscles is reported. By a facile supramolecular self‐assembly, the Ti3C2Tx‐MnBTC hybrid nanoarchitecture forms coordinate bond, hydrogen bond, and hydrophilic interaction with the conducting polymer of poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), resulting in a mechanically flexible and electro‐ionically active electrode. The superior electrical and electrochemical performances of the electrode stem from the synergistic effects between intrinsically hierarchical nanoarchitecture of MnBTC and rapid electron transport behavior of Mxene, leading to fast diffusion and accommodation of ions in the ion‐exchangeable membrane. The developed artificial muscle based on Ti3C2Tx‐MnBTC is found to exhibit high bending displacement (12.5 mm) and ultrafast response time (0.77 s) under a low driving voltage (0.5 V), along with wide frequency response (0.1–10 Hz) and exceptional stability (98% retention at 43,200 s) without any distortion of actuation performance. Furthermore, the designed electro‐active artificial muscle is successfully used to demonstrate mimicry of eye motions including eyelid blinking and eyeball movement in a doll.

Metal-Organic Framework-Derived Fe-Doped Ni3Se4/NiSe2 Heterostructure-Embedded Mesoporous Tubes for Boosting Oxygen Evolution Reaction.

It is crucial but challenging to promote sluggish kinetics of oxygen evolution reaction (OER) for water splitting via finely tuning the hierarchical nanoarchitecture and electronic structure of the catalyst. To address such issues, herein we present iron-doped Ni3Se4/NiSe2 heterostructure-embedded metal-organic framework-derived mesoporous tubes (Ni-MOF-Fe-Se-400) realized by an interfacial engineering strategy. Due to the hierarchical nanoarchitecture of conductive two-dimensional nanosheet-constructed MOF-derived mesoporous tubes, coupled with fine tuning of the electronic structure via Fe-doping and interactions between Ni3Se4/NiSe2 heterostructures, the Ni-MOF-Fe-Se-400 catalyst delivers superior OER activity: it requires only a low overpotential of 242 mV to achieve 10 mA cm-2 (Ej=10), surpassing the benchmark RuO2 (Ej=10 = 286 mV) and displays exceptional durability in the chronoamperometric i-t test with a small current decay (6.2%) after 72 h. Furthermore, the water splitting system comprises a Ni-MOF-Fe-Se-400 anode and a Pt/C cathode requires a low cell voltage of 1.576 V to achieve Ej=10 with an excellent Faradic efficiency (∼100%), outperforming the RuO2-Pt/C combination. This work presents a novel interfacial engineering strategy to finely adjust the morphology and electronic structure of the non-noble metal-based OER catalyst via a facile fabrication method.

Biomimetic platinum forest enables 3D micro-supercapacitors with enhanced areal performance

Nowadays, the rapid development of portable micro-electronics has stimulated a significantly increasing demand in micro-supercapacitors (MSCs) for efficient micropower sources. However, the performance of MSCs is hindered by the dense electrode design with sluggish ion diffusion or reaction kinetics and tortuous charge transfer pathways, especially at high mass loading. Inspired by the structure of natural forest with efficient solar energy utilization, we fabricate an innovative biomimetic Pt forest (named forest-like Pt) as a robust three-dimensional (3D) conductive current collector by a simple one-step electrodeposition process. This hierarchical nanoarchitecture significantly improves the exposed surface areas of active electrode materials. As a proof-of-concept, 3D MSCs based on poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer grown on such forest-like Pt exhibit an enhanced areal capacitance of 69.3 mF cm−2 at 0.1 mA cm−2, which is more than 5-fold larger than that of pristine PEDOT-based MSCs using conventional flat Au current collectors. Furthermore, the assembled 3D MSCs show a high areal energy density (6.16 μW h cm−2) and outstanding rate capability (63.2 mF cm−2 even at 5 mA cm−2). Thus, this novel design concept provides a new approach to build advanced electrode nanoarchitectures for the next-generation MSCs.