Hierarchical Nanostructures Research Articles

Copper restructured transition metal/metal oxide heterostructure with a hierarchical nanostructure for accelerated water dissociation kinetics and alkaline hydrogen evolution

The slow kinetics of water dissociation on electrocatalysts lacking platinum hinders the advancement of cost-effective hydrogen production via alkaline water electrolysis. Herein, a hierarchically peach-flower-shaped electrocatalyst consisting of copper-restructured cobalt–nickel/cobalt–nickel oxide heterostructure anchored on copper nanowires (Cu-CoNiO/CoNi@Cu NWs) is developed for efficient hydrogen evolution reaction (HER). Benefiting from the optimized electronic configuration and geometric structure, this Cu-CoNiO/CoNi@Cu NWs catalyst performs an outstanding alkaline HER activity of 29 mV at 10 mA cm−2 and 98 mV at 100 mA cm−2, which is comparable with the state-of-the-art Pt/C catalyst (26 mV at 10 mA cm−2 and 117 mV at 100 mA cm−2). Our findings rank among the topmost catalytic efficiencies when compared to all previously reported non-noble metal catalysts and numerous noble metal catalysts. The combined experimental exploration and theoretical studies reveal that the incorporation of Cu dopant into CoNiO/CoNi heterostructure enhances electron transfer from metal atoms to O atom, leading to the formation of the polarized electric field to accelerate water dissociation and H evolution, eventually facilitating the overall alkaline HER process. The boosted electron exchange and mass transportation deriving from the introduction of Cu NWs and hierarchically peach-flower-shaped nanostructure further reinforce the HER activity of the Cu-CoNiO/CoNi catalyst.

Two birds with one stone: Bimetallic ZnCo2S4 polyhedral nanoparticles decorated porous N-doped carbon nanofiber membranes for free-standing flexible anodes and microwave absorption

Cost-efficient material with an ingenious design is important in the engineering applications of flexible energy storage and electromagnetic (EM) protection. In this study, bimetallic ZnCo2S4 (ZCS) polyhedral nanoparticles homogenously embedded in the surface of porous N-doped carbon nanofiber membranes (ZCS@PCNFM) have been fabricated by electrospinning technique combined with carbonization and hydrothermal processes. As a self-assembled electrode for lithium-ion batteries (LIBs), the bimetallic ZCS nanoparticles possess rich redox reactions, good electrical conductivity, and pseudocapacitive properties, while the three-dimensional (3D) multiaperture architecture of the nanofiber film not only shortens the transfer spacing of lithium ions and electrons but also effectively tolerates the volume variation during lithiation and delithiation cycles. Benefiting from the above merits, the ZCS@PCNFM electrode exhibits good cycle performance (662.3 mA h/g at 100 mA/g after 100 cycles), superior rate capacity (401.3 mA h/g at 1 A/g) and an extremely high initial specific capacity of 1152.2 mAh/g at 100 mA/g. Meanwhile, depending on the hierarchical nanostructure and multi-component heterogeneous interface effects constructed by 3D inlaid architecture, the ZCS@PCNFM nanocomposite exhibits fascinating microwave absorption (MA) characteristics with a superhigh reflection loss (RL) of –49.7 dB at a filling content of only 20 wt% and corresponding effective absorption bandwidth (EAB, RL<–10 dB) of 5.2 GHz ranging from 12.8 to 18.0 GHz at 2.2 mm.

MOF-derived Mo-doped Co3O4: A hierarchical yeast-like structure for superior carbon monoxide sensing

Carbon monoxide (CO) is one of the most dangerous gases owing to its dual threat, role in global warming, and severe impact on human health. Metal-organic framework (MOF) gas-sensing materials have drawn the interest of many different sectors due to their unique structural characteristics. This study used a solvothermal technique and subsequent annealing to create a hierarchical, yeast-shaped Mo-Co3O4 material from a Co-MOF precursor. The prepared materials have been employed in the development of a CO-detection gas sensor. Gas-sensing experiments revealed that Mo-Co3O4 exhibited significantly improved sensing capabilities compared to pure Co3O4. Notably, at 200 °C, 2 mol% Mo-Co3O4 showed high response levels of about 136 at 100 ppm CO concentrations, approximately 50.4 times higher than pure Co3O4. Furthermore, the Mo-doped material exhibited a low detection threshold, excellent reproducibility, long-term stability, good selectivity, and rapid response and recovery times (78.5/55.3 s). Introducing Mo dopants into the Co3O4 material and the hierarchical yeast-like nanostructure are responsible for these improvements in gas-sensing capability.

Hierarchical Nanostructures Constructed by Soft Epitaxial Self-Assembly of Organic-Inorganic Hybrid Giant Amphiphiles.

2D nanomaterials with ångström-scale thicknesses offer a unique platform for confining molecules at an unprecedentedly small scale, presenting novel opportunities for modulating material properties and probing microscopic phenomena. In this study, mesogen-tethered polyhedral oligomeric silsesquioxane (POSS) amphiphiles with varying numbers of mesogenic tails to systematically influence molecular self-assembly and the architecture of the ensuing supramolecular structures, are synthesized. These organic-inorganic hybrid amphiphiles facilitate precise spatial arrangement and directional alignment of the primary molecular units within highly ordered supramolecular structures. The correlation between molecular design and the formation of superlattices through comprehensive structural analyses, incorporating molecular thermodynamics and kinetics, is explored. The distinct intermolecular interactions of the POSS core and the mesogenic tails drive the preferential formation of a 2D inorganic sublattice while simultaneously guiding the hierarchical assembly of organic lamellae via soft epitaxy. The findings reveal the intricate balance between shape, size, and interaction strengths of the inorganic and organic components, and how these factors collectively influence the structural hierarchy of the superstructures, which consist of multiple sublattices. By controlling this unique molecular behavior, it is possible to modulate or maximize the anisotropy of optical, mechanical, and electrical properties at the sub-nanometer scale for nanotechnology applications.

In-situ constructed NiCoZnS composite on nickel foam with hierarchical structures as bifunctional electrocatalysts for oxygen evolution reaction (OER) and supercapacitors

Transition metal sulfides have shown promise as candidates for energy storage and conversion devices, but the limited electroactive sites may greatly hinder further improvement. The novel nanostructured morphologies enhance active sites and surface area, thereby increasing overall electrochemical performance. Herein, we successfully synthesized various morphologies such as ZnS spheres, CoS star anise spice-like structures, and NiS flakes-like structures, which were directly grown on Ni foam using a single-step hydrothermal method. Additionally, the novel nanostructured morphologies were combined as a heterojunction NiCoZnS electrode to further utilize electronic and junction properties, thereby enhancing performance. This combination of morphologies—spheres, star anise spice, and flakes-like structures with ultrathin thickness and large surface areas—effectively increases the number of active sites, resulting in enhanced supercapacitor and oxygen evolution reaction (OER) performance. Moreover, directly growing nanostructures on conductive Ni foam endows the electrode materials with higher conductivity and richer active sites. In terms of supercapacitor performance, the NiCoZnS electrode exhibits a specific capacity of 1171.3 C g−1 at 0.5 A g−1 and remarkable rate performance. Furthermore, NiCoZnS maintains a capacitance retention of 94.9 % after 5000 cycles. As an electrocatalyst, NiCoZnS undergoes a rapid self-reconstruction process during the oxygen evolution reaction (OER), producing rich oxygen vacancies and thus demonstrating remarkable long-term stability. The NiCoZnS nanocomposites exhibit small overpotential (157 mV at 100 mA cm−2) and a Tafel slope of 128 mV dec−1. NiCoZnS's unique hierarchical nanostructures, doping-optimized electronic structural configuration, and specific surface lead to high catalytic performance. These remarkable performances of mixed morphologies like NiCoZnS hold great promise for energy storage and conversion devices.

Fast fabrication of a hierarchical nanostructured multifunctional ferromagnet.

Materials with multifunctionality affect society enormously. However, the inability to surmount multiple functionality trade-offs limits the discovery of next-generation multifunctional materials. Departing from conventional alloying design philosophy, we present a hierarchical nanostructure (HNS) strategy to simultaneously break multiple performance trade-offs in a material. Using a praseodymium-cobalt (PrCo5) ferromagnet as a proof of concept, the resulting HNS outperforms contemporary high-temperature ferromagnets with a 50 to 138% increase in electrical resistivity while achieving their highest energy density. Our strategy also enables an exceptional thermal stability of coercivity (-0.148%/°C)-a key characteristic for device accuracy and reliability-surpassing that of existing commercial rare-earth magnets. The multifunctionality stems from the deliberately introduced nanohierarchical structure, which activates multiple micromechanisms to resist domain wall movement and electron transport, offering an advanced design concept for multifunctional materials.

Yolk-Shell Hierarchical Pore Au@MOF Nanostructures: Efficient Gas Capture and Enrichment for Advanced Breath Analysis.

Surface-enhanced Raman scattering (SERS) offers a promising, cost-effective alternative for the rapid, sensitive, and quantitative analysis of potential biomarkers in exhaled gases, which is crucial for early disease diagnosis. However, a major challenge in SERS is the effective detection of gaseous analytes, primarily due to difficulties in enriching and capturing them within the substrate's "hotspot" regions. This study introduces an advanced gas sensor combining mesoporous gold (MesoAu) and metal-organic frameworks (MOFs), exhibiting high sensitivity and rapid detection capabilities. The MesoAu provides abundant active sites and interconnected mesopores, facilitating the diffusion of analytes for detection. A ZIF-8 shell enveloping MesoAu further enriches target molecules, significantly enhancing sensitivity. A proof-of-concept experiment demonstrated a detection limit of 0.32 ppb for gaseous benzaldehyde, indicating promising prospects for the rapid diagnosis of early stage lung cancer. This research also pioneers a novel approach for constructing hierarchical plasmonic nanostructures with immense potential in gas sensing.

Biotemplate synthesis of SnO2 hollow porous structures for enhanced isopropanol sensing performance

Researchers are showing significant interest in the development of nanostructures with hierarchical porosity. This study introduces an eco-friendly, cost-effective, and straightforward method to create SnO2 hollow porous nanostructures using the peony as a biotemplate. A comprehensive analysis of the gas sensing characteristics of these hierarchical SnO2 hollow porous nanostructures is conducted. The results show that the gas sensor based on SnO2 showcases relatively high response values measuring 18.3 and exhibits rapid response speed of 1 s to 100 ppm isopropanol, even at a comparably low operating temperature of 180 °C. Additionally, the sensor displays good repeatability and long-term stability, which can be attributed to the inherent advantages stemming from its distinct structure. Therefore, this study provides experimental and theoretical foundations for the potential application of hollow porous SnO2 structures in sensor technology.

CHITOSAN / HEXAMOLYBDATE NANOSTRUCTURES FOR ORAL DRUG DELIVERY

Background: In recent decades, substantial progress has been achieved in the field of drug delivery through the creation of controlled-release formulations, leading to significant medical advancements. The primary objective of these controlled release systems is to sustain the desired drug concentration in the bloodstream or specific tissues for an extended duration. One class of nanostructures is polyoxometalates (POMs), which are negatively charged anionic nanoclusters consisting of metal and oxygen atoms. POMs are notable for their ability to be precisely controlled in size and shape. These characteristics, combined with their inherent negative charge, contribute to their stability and make them highly versatile structures. Aim: This study aimed to examine the self-assembly of organic-inorganic hybrids using polyoxometalate (POM) Lindqvist-type hexamolybdate and chitosan to synthesize novel 3D nanostructures. These nanostructures were then investigated for their suitability as nanocarriers for the chemotherapy drug )Temozolomide TMZ(. The release of TMZ from the nanocarrier was studied under various pH conditions. Methods: This study comprises two practical components. The first part focuses on synthesizing hierarchical nanostructures designed to load TMZ drugs. The amount of drug loaded onto the as-prepared nanostructure of POM-Chitosan was determined using High-Performance Liquid Chromatography (HPLC) at various loading times. The second part of the study investigates the release process of the TMZ drug from the hierarchical nanostructures. This release process is examined in two buffer solutions with distinct pH values. Results: The surface characteristics, size, chemical composition, and identity of the nanostructures were confirmed using techniques such as HPLC, FTIR, XRD, SEM, and XPS. The results confirm the successful complexation of chitosan with POM Lindqvist-type hexamolybdate. Discussion: The nanocarriers demonstrated an intriguing pH-dependent release behavior, suggesting their potential application in drug delivery systems. Conclusions: In this study, new nanocarriers of chitosan and POM were successfully prepared and loaded with TMZ (21% loading) via self-assembly for oral drug delivery. The as-prepared nanocarrier form of TMZ was fully characterized via XRD, FTIR, XPS, and SEM. The as-prepared oral form of TMZ showed an excellent pH-dependent release of TMZ, where the release rate at pH 7.4 was considerably faster than at pH 2.8.

Novel three-dimensional architectured ZnMgAl ternary layered double hydroxide@reduced graphene oxide nanocomposites as electrode material for high-performance supercapacitor

Ternary layered double hydroxides (LDH) have recently attracted immense attention owing to their stupendous features, such as fine compositional tuning, multiple valence states, and superior electrochemical activity. Moreover, their intriguing structures and distinctive physiochemical properties delineate them as an exemplary material to serve as electrodes for high-performance supercapacitors (SCs). The present work reports the in-situ synthesis of Zinc Magnesium Aluminium LDH (ZMA) integrated with reduced graphene oxide (rGO) through a single-step hydrothermal approach. The resulting novel ternary ZMA@rGO nanocomposite (ZMAG) possesses a unique architecture incorporating hierarchical 3D nanoflowers of ZMA embedded on graphene nanosheets. The porous morphology of LDH improves interfacial charge transport, which results in more faradaic reactions at the electrochemically active sites. In addition, the conductive graphene nanosheets render a high specific surface area, endowing excellent capacitive behavior. The amalgamated electrochemical properties of ZMA and rGO develop a competent electrode material (ZMAG) for SCs. The ZMAG2 nanocomposite having ZMA and rGO in 1:1, evinces a specific capacitance (Cs) of 656.7 F/g at a current density (Id) of 1 A/g. Furthermore, the asymmetric supercapacitor (ASC) features admirable cycle stability (retains 89% of initial capacitance after 15,000 charge/discharge cycles). Herein, the real-time application of ZMA@rGO//AC ASC has also been demonstrated. Therefore, hierarchical porous nanostructure proclaims new prospects for fabricating proficient electrode materials for energy storage devices.

Critical microstructural modifications of Cu/Zn/Al2O3 catalyst during CO2 hydrogenation to methanol

This contribution reports the impact of the reaction pressure (1, 10, 20 and 30 bar) on the deactivation of the commercial catalyst Cu/ZnO/Al2O3 during the CO2 hydrogenation to CH3OH. The best performance was obtained at 30 bar with ≈ 30 % of initial CO2 conversion (XCO2) and CH3OH space-time-yield (STYMEOH) of 255 mgMeOH/gcat.h. Although the initial conversion decreased drastically the activity was kept along all the reaction time, ≈ 5 %. The analysis of fresh and post-reaction samples using X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Electron Microscopy (SEM-FEG, STEM, HRTEM), and Raman Spectroscopy demonstrated profound microstructural changes, characterized by phase sintering, formation of Cu-aluminate, segregation of phases, an imbalance among Cu-species, as well as the presence of coke. As the catalyst Cu/ZnO/Al2O3 has a particular microstructure, these modifications provoked the loss of the geometric configuration of the active sites, which might also originate a disturbance in the electronic interactions, resulting in activity loss. HRTEM and STEM image (dark field) of the passivated sample showed the presence of crystalline nanostructures (d < 4 nm) attributed to Cu0, surrounded by amorphous phases. STEM images of spent samples also reveals the development of hierarchical and elongated nanostructures spread on all the spent catalysts. This result foresees the co-existence of small nanoparticles (< 5 nm) with large ones in all the catalyst surface, corroborating XRD results. It is noteworthy that the hydrothermal environmental developed inside the reactor originated from the high pressure and the continuous H2O production, both which may favor the phase sintering and aluminate formation.

Strong Interaction between Molybdenum Compounds and Mesoporous CMK‐5 Supports Boosts Hydrogen Evolution Reaction

AbstractStrong metal‐support interaction (SMSI) between transition metal nanoparticles and carbon matrix offers significant structure advantages due to the ability to modulate the electronic structure of metal nanoparticles, increase the density of active sites, and improve the conductivity of catalysts. Here, ultrafine nanoparticles of metallic molybdenum compounds (MoP, Mo2C, and MoS2) strongly coupled with mesoporous carbon CMK‐5 are synthesized. The confinement growth of nanoparticles in the pores of CMK‐5 produces encapsulated nanoparticles, affording facilitated electron transfer, and enhancing the HER activity induced by the SMSI effect. The hierarchical nanostructure and strong electronic interactions between the carbon substrate and molybdenum‐based nanoparticles allow efficient mass/electron transport between the carbon substrate and molybdenum‐based nanoparticles, improving the catalytic hydrogen evolution reaction (HER) activity. The effective electron exchange between the Mo species and the CMK‐5 support is studied by X‐ray photoelectron spectroscopy (XPS) measurement, confirming the presence of the SMSI effect. The resulting MoP/CMK‐5 catalyst exhibits outstanding HER performance in alkaline (65 mV@10 mA cm−2), acidic (123 mV@10 mA cm−2), and simulated seawater electrolytes (103 mV@10 mA cm−2), making it one of the most promising catalysts reported for HER. This work provides guidance on designing high‐performance electrocatalysts with SMSI for the enhancement of the electrochemical reaction.

Advancing X‐Band Electromagnetic Interference Shielding: Single‐Layer Thin Films of Fe3O4‐MWCNT (1:2)‐PVDF Meta‐Nanocomposite Fabricated by Low‐Cost Drop‐Casting Process

This study, investigate of ternary thermoplastic fluoropolymer blend nanocomposite (NC) system for improved microwave (MW) shielding, consisting of polyvinyl dimethylamine fluoride (PVDF) and Fe3O4‐multiwalled carbon nanotube (MWCNT) (1:2) NC. Using a hydrothermal process, complex hierarchical nanostructures (NSs) of Fe3O4‐MWCNT (1:2) NC are produced. These NSs are then integrated using a drop‐casting technique into PVDF matrices with different wt% (20, 40, and 60 wt%) and thicknesses (20, 50, and 80 μm). The single‐layer thin films (SLFs) with the Fe3O4‐MWCNT (1:2)‐PVDF matrix are successfully produced as a consequence of this approach. The presence of FeOC bonding from X‐ray photoelectron spectroscopy (XPS) analysis confirms chemical interaction, while scanning electron microscopy (SEM–Energy dispersive spectroscopy EDX) imaging analysis for material homogeneity. Moreover, the SLFs of Fe3O4‐MWCNT (1:2)‐PVDF (20, 40, and 60 wt% for 80 μm thickness) are newly discovered meta‐nanocomposites (MNCs) properties, which are evidenced by negativeMW real complex permittivity (−274.4, −271.2, and −136.4), superior attenuation constant (12862.73, 16265.18, and 12256.34), and higher alternating current (AC)electrical conductivities (1020.8, 1174.6, and 727.7 S m−1). The synergistic impact of higher attenuation and AC conductivity of MNCs results in an increased average MW shielding effectiveness of ≈33.28 dB for Fe3O4‐MWCNT (1:2)‐PVDF 20 wt% MNCs (≈80 μm).

Advancing electrochemical activity: Insights from Li doped Ni-MOF synthesis and performance

This study presents the first-time synthesis of a novel Li doped Ni-MOF electrode material, achieved via a one-step hydrothermal strategy. Microstructural analysis using FESEM and HRTEM revealed hierarchical hollow spherical-like nanostructures within the Li doped Ni-MOF, providing abundant active sites for ion transport and storage. This structural feature resulted in enhanced specific capacity, exhibiting battery-like behaviors. Specifically, the Li doped Ni-MOF electrode displayed a notable specific capacity of 214.2 C/g in CV curves at 0.5 mV/s and 814 C/g in GCD curves at 1 A/g. These findings underscore the potential of the Li doped Ni-MOF as a superior electrode material for supercapacitors, indicating its promising prospects for advancing next-generation high-performance energy storage devices.

Synthesis of ZnO@Fe2O3 microflowers with enhanced performance in volatile organic compound detection

Metal-oxide semiconductor is widely applied in gas sensor for volatile organic compound detection. However, these sensors usually exhibit poor selectivity and inferior sensitivity. Here, ZnO@Fe2O3 microflowers were synthesized using FeOOH microflowers as precursors via a simple solution reaction route, followed by heat treatment. The ZnO@Fe2O3 microflowers were characterized using a series of techniques, and their sensing responses to volatile organic compounds (VOCs) were evaluated in comparison with those of pristine Fe2O3. The ZnO@Fe2O3 microflower sensor exhibited better responses to several gases, especially acetone, with a response of 74.3 towards 100 ppm acetone, which is 2.85 times higher than that of the Fe2O3 microflower sensor. The sensor also presented high selectivity, reproducibility, and stability in sensing different VOCs. The large specific surface area, heterostructure, favorable hierarchical flower-like nanostructure assembled by the nanosheets, and high porosity of the ZnO@Fe2O3 microflowers contributed to its enhanced gas-sensing responses. Overall, this synthetic strategy for fabricating flower-like ZnO@Fe2O3 nanostructures can be widely applied.

Hierarchical metal–organic framework nanoarchitectures for catalysis

Metal–organic frameworks (MOFs) have garnered significant attention in the field of catalysis due to their unique advantages such as diverse coordination geometry, variable metal nodes, and organic linkers, facilitating precise structural and compositional control for achieving programmable catalytic functionalities. Although their inherent microporous structure could provide excellent shape selectivity during catalysis, it typically impedes the mass transfer process, thereby reducing the use of internal active sites and overall catalytic efficiency. Additionally, employing single MOFs as catalysts presents challenges in achieving complex catalytic reactions that require multifunctional active sites. In recent years, considerable research efforts have focused on designing and constructing hierarchical nanostructured MOFs to alleviate substrate diffusion limitations by introducing secondary nanopores, shortening diffusion distances via the construction of low-dimensional nanoarchitectures, and constructing multifunctional catalysts by integrating distinct MOFs with suitable functions. This review provides a comprehensive overview of the design, synthesis methods, and formation mechanisms of MOF-based hierarchical nanostructures in recent years. Subsequently, it further highlights their applications in thermal catalysis, electrocatalysis, and photocatalysis, along with the relationship between their hierarchical nanostructures and catalytic performances. Finally, it provides an outlook on the challenges and potential development directions of hierarchically structured MOF nanocatalysts.

Fabrication of 3D CuFe2O4/Cu0 hierarchical nanostructures on carbon fiber paper by simple hydrothermal method for efficient detection of malachite green, sunset yellow and tartrazine in food samples

In this study, a hydrothermal process was utilized to grow mixed-valence CuFe2O4/Cu0 nanosheets on carbon fiber paper, forming a three-dimensional hierarchical electrode (CuFe2O4/Cu0@CFP). The ordered array structure, coupled with the porous bowl-like structure, enhances the exposure of more electrode active sites and facilitates analyte penetration, thus enhancing the electrode sensing performance. As a binder-free sensor, the CuFe2O4/Cu0@CFP sensor exhibited remarkable sensitivity in detecting Malachite Green (MG), Sunset Yellow (SY) and Tartrazine (TA) over wide concentration ranges: 0.1–300 μM for MG (R2 = 0.994), 0.005–200 μM for SY (R2 = 0.996), and 0.005–300 μM for TA (R2 = 0.995) with low detection limits of 0.033 μM for MG, 0.0016 μM for SY, and 0.0016 μM for TA (S/N = 3), respectively. Additionally, the 3D CuFe2O4/Cu0@CFP sensor detected MG, SY, and TA in a mixed solution with satisfactory results. It also performs well in beverage, fruit juice powder, and jelly samples, with results matching those from HPLC.

Enhancing efficiency of photoelectrochemical water splitting using zinc vanadate nanosheets (ZV) on manganese vanadate needle flowers (MV) supported by carbon nanofibers

Zinc and Manganese vanadates are highly regarded as potential photoanode materials for photoelectrochemical (PEC) water splitting due to their limited bandgap, varying optical and electrical characteristics based on their composition, and robust nature. To advance the practical use these materials, it is essential to creating precisely composed and structured Zinc and Manganese vanadates to enhance their overall effectiveness. In this work, we employed various morphologies, such as nanobelt flower like Zinc vanadate (ZV), nano-needle like Manganese vanadate (MV), a composite with ZV and MV, and a ZV-MV@CNF ternary composition. These novel morphologies grown on ITO substrate using a simple, hydrothermal approach without using any seed layer. The structural, surface, and optical examinations confirmed that the ZV-MV@CNF catalyst had superior visible light absorption, accelerated charge transfer, heterojunction interface between ZV and MV, and increased electron mobility, leading to outstanding photoelectrochemical performance. The photocurrent density of the ZV-MV@CNF photoanode reached 6.59 mA cm−2 at 1 V versus Ag/AgCl in a 0.25 M KOH solution under the illumination light. These results are ∼3.00, 3.52, and 1.28 times greater than the pristine ZV, MV, and ZV-MV, respectively. The fine-tuned ZV, MV, ZV-MV, and ZV-MV@CNF electrodes showed applied bias photon to current efficiency (ABPE) values of 0.09 %, 0.06 %, 0.14 %, and 0.18 %, respectively. The improved photoelectrochemical behavior of the ZV-MV@CNF electrode is credited to the excellent light absorption, and the remarkable catalytic and charge transport capabilities of CNFs. Therefore, these experimental results and characterization analysis suggested that advanced hierarchical nanostructures hold significant promise for water splitting applications.

Constructing the synergistic active sites of nickel bicarbonate supported Pt hierarchical nanostructure for efficient hydrogen evolution reaction

Constructing synergistic active sites and optimizing the cooperative adsorption energies for hydrogen and hydroxyl based intermediates are two essential strategies to improve the sluggish kinetics of hydrogen evolution reaction (HER) in alkaline medium. However, it is still in its infancy to simultaneously achieve these goals, especially for designing a well-defined carrier with multiple hydroxyl adsorption sites. Herein, the Ni(HCO3)2 nanoplates (NHC) with horizontal interfaces sites of Ni-terminated NiO, NiOOH, NiCOO, and Ni(OH)2 were employed as the hydroxyl adsorption active sites, which could anchor Pt particles with hydrogen adsorption active sites, constructing the synergistic active sites (NHC-Pt) for HER catalysis. Evidenced by X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS), the NHC could affect the chemical state and electronic structure of Pt particles by forming bond of Pt-O which could reduce the reaction energy barriers, facilitate the adsorption of hydrogen and establishment of H–H bond. Furthermore, density functional theory (DFT) theoretical calculation revealed that the related process of hydroxide was the rate-determining step. It is demonstrated the hydroxyl group presents the lowest energy barrier for desorption in the process of HER when the gradual desorption process could be described as a migration from Ni(HCO3)2·OH directly or via other Ni-based systems formed after partial decomposition of nickel hydrocarbonate to Ni(OH)2···OH with following desorption. As a result, the NHC-Pt hierarchical nanostructure demonstrated superior activity towards HER in a pH-universal solution. This enhancement can be attributed to the optimized electronic structure of Pt, the migration of hydroxyl group on NHC substrates, and the synergistic effects between the NHC carrier and Pt particles.

Jellyfish-Inspired Self-Healing Luminescent Elastomers Based on Borate Nanoassemblies for Dual-Model Encryption.

Responsive luminescent materials that reversibly react to external stimuli have emerged as prospective platforms for information encryption applications. Despite brilliant achievements, the existing fluorescent materials usually have low information density and experience inevitable information loss when subjected to mechanical damage. Here, inspired by the hierarchical nanostructure of fluorescent proteins in jellyfish, we propose a self-healable, photoresponsive luminescent elastomer based on dynamic interface-anchored borate nanoassemblies for smart dual-model encryption. The rigid cyclodextrin molecule restricts the movement of the guest fluorescent molecules, enabling long room-temperature phosphorescence (0.37 s) and excitation wavelength-responsive fluorescence. The building of reversible interfacial bonding between nanoassemblies and polymer matrix together with their nanoconfinement effect endows the nanocomposites with excellent mechanical performances (tensile strength of 15.8 MPa) and superior mechanical and functional recovery capacities after damage. Such supramolecular nanoassemblies with dynamic nanoconfinement and interfaces enable simultaneous material functionalization and self-healing, paving the way for the development of advanced functional materials.