Ultrafine Metal Nanoparticles Research Articles

Generalized Synthesis of Highly-Dispersed, Ultrafine Transition Metal Nanoparticles on Silica Spheres for Enhanced Optical Absorption.

Robust synthesis of ultrafine metal nanoparticles (ufMNPs) below 5nm with clean surfaces and strong optical absorption in the visible spectral range is challenging due to their instability originating from large surface-to-volume ratios. This work reports a general strategy involving two sequential steps: i) loading metal precursor ions onto the surface of silica nanospheres (SiOx NSs) by forming a uniform coating of metal oxyhydroxide [MOy(OH)z] through preferred surface acid-base reactions and ii) thermally reducing MOy(OH)z in forming gas at elevated temperatures to form ufMNPs evenly dispersed on the surface of SiOx NSs. The capability of this synthesis strategy is verified by loading ufMNPs of various transition metals and bimetallic combinations onto the SiOx NSs. The ufMNPs exhibit strong optical absorption enhanced by the optical scattering resonances in the SiOx NSs, which generate intense electric fields near the surface of the SiOx NSs. The SiOx NSs also support stabilizing the ufMNPs, which do not need additional organic capping reagents. The successful synthesis of SiOx-NS-supported ufMNPs with clean surfaces and enhanced optical absorption is promising for exploring the photocatalytic properties of ufMNPs.

A universal and ultrafast method for fabricating a library of nanocellulose-supported metal nanoparticles

Using nanocatalysts to catalyze water electrolysis for hydrogen production is an ideal solution to address the energy crisis. The most well-adopted fabrication methods for nanocatalysts are tube furnace annealing, Hydrothermal method, etc., hardly satisfying the trade-off among coarsening, dispersity, and particle size due to mutual restrictions. Herein, a universal, ultrafast and facile cellulose nanometer whiskers-high temperature shock (CNW-HTS) method was reported for fabricating a library of ultrafine metal nanoparticles with uniform dispersion and narrow size distribution. The metal-anchor functional groups in CNW (i.e., –OH and –COOH) and the characteristics of the HTS method for ultrafast heating and powerful quenching synergistically contribute to the successful synthesis of metal nanoparticles. As an initial demonstration, the as-prepared Pt nanocatalyst (η10 ​mA ​cm−2 ​= ​51.8 ​mV) shows more excellent catalytic hydrogen evolution reaction (HER) performance than the Pt catalyst prepared in the tubular furnace (η10 ​mA ​cm−2 ​= ​169.4 ​mV). This rapid and universal CNW-HTS method can pave the way for nanomanufacturing to produce high-quality metal nanoparticles, thereby expanding applications of energy conversion and electrocatalysis.

A novel Co–CoAl2O4/exfoliated montmorillonite composite with improved nanoparticle dispersion for methyl orange removal via coupling peroxydisulfate

The degradation of refractory pollutants via the activation of peroxydisulfate (PDS) by Co-based nanostructures as catalysts has been gaining significant attention. However, most cobalt-based catalysts suffer from severe aggregation and metal ion leakage, resulting in a loss of activity and potential environmental threats. In this study, exfoliated montmorillonite (EMMT) loaded Co–CoAl2O4 composites were elaborately constructed through a facile coprecipitation-reduction method. The effects of the calcination temperature, the EMMT addition content, the pH of the precursor, and the reduction temperature on the microstructure of the Co–CoAl2O4/EMMT composites were investigated, and the optimum synthesis conditions were determined. In the optimal sample, well-crystallized CoAl2O4 nanoparticles were uniformly deposited onto the EMMT nanosheets with a considerably large specific surface area, while ultrafine metallic Co nanoparticles were homogeneously immobilized on the CoAl2O4 surface. This sample exhibited a superior activity (90% within 70 min) and reusability during methyl orange (MO) degradation. In the catalytic reaction, the superior adsorption property of EMMT facilitated the rapid transfer of MO molecules to the catalytically active sites. Moreover, CoAl2O4 acted as a transition layer which provided a cobalt source for the subsequent reduction process and regulated the growth of metallic Co nanoparticles, which increased the number of active sites for catalysis. Simultaneously, the metallic Co can not only activate PDS by being an electron donor, but also initiate the formation of Co-based redox pairs. This study offers new insights into the synthesis of efficient and cost-effective supported Co-based catalysts.

Ultrafine Pd on a La Metal–Organic Framework for Selective Hydrogenation of Furfural via a Metal–Support Electronic Effect

It is challenging to synthesize a stable ultrafine Pd catalyst with high selectivity and activity at low temperatures toward hydrogenation of furfural (FF). We report an approach of applying C═N and S–O entities in a highly stable La metal–organic framework (La-MOF) (LaQS) as the platform support that confines Pd nanoparticles (NPs) through coordination, resulting in a stable Pd/LaQS catalytic system. The catalytic conversion of FF into tetrahydrofurfuryl alcohol (THFA) using this catalyst can be done as simply as one-step hydrogenation at room temperature, with a high selectivity of >99% maintained even at 120 °C. The outstanding catalytic activity and selectivity are mainly attributed to the electronic effect of metal–support in Pd/LaQS, which produces electron-rich Pd and enhanced Lewis-acid LaQS. Especially, this electronic effect can be facilely tuned by the Pd loading in Pd/LaQS. On the one hand, electron-rich ultrafine Pd promotes the activation of H2 and improves the reaction activity. On the other hand, the acid-enhanced LaQS support not only promotes the activation of FF and improves its activity, but also the positive electricity of the LaQS support is conducive to the reactant adsorption and product desorption, thus improving the THFA selectivity. This work develops a stable LaQS support for the stabilization of ultrafine metal nanoparticles via the metal–support interaction for enhanced catalysis, which sheds light on the construction of efficient MOF-based catalysts for task-specific applications.

自还原法合成超小尺寸钯加氢催化剂

Supported ultrafine metal nanoparticles display outstanding catalytic performance in heterogeneous catalysis. Nevertheless, there are limited convenient and practical approaches for synthesizing supported ultrafine metal nanoparticle catalysts, despite the development of advanced fabrication methods. High-temperature reduction is often required for the preparation of metal catalysts for catalytic hydrogenation. However, the use of reductants, such as H2, easily leads to the aggregation of nanoparticles during catalyst preparation. In this work, we developed an effective self-reduction strategy using Pd precursors with organic ligands to prepare supported ultrafine Pd catalysts. Simple calcination under an inert atmosphere leads to the formation of uniform and ultrafine Pd nanoparticles (∼1 nm). These Pd precursors were reduced following the reaction between the −CHx groups on ligands and surface hydroxyl species on oxide supports. CO and oxygen vacancies generated in situ both contributed to the stabilization of ultrafine Pd nanoparticles. The as-prepared ultrafine Pd nanoparticles were highly stable even after the high-temperature treatment at 600°C. The catalysts displayed a turnover frequency as high as 26,910 h−1 for styrene hydrogenation and maintained the catalytic activity for at least 5 test cycles.

Chelating adsorption-engaged synthesis of ultrafine iridium nanoparticles anchored on N-doped carbon nanofibers toward highly efficient hydrogen evolution in both alkaline and acidic media

Developing highly efficient and stable precious metal electrocatalysts toward hydrogen evolution reaction (HER) is crucial for energy application, while it is still challenging to achieve highly dispersed ultrafine metal nanoparticles on some promising supports to synergistically promote their electrocatalytic performance. Herein, we propose a feasible chelating adsorption-engaged strategy by introducing de-doped polyaniline with abundant amino groups to immobilize ultrafine iridium (Ir) nanoparticles on their derived N-doped carbon nanofibers (Ir-NCNFs). Experimental results demonstrate that the synthesized Ir-NCNFs can effectively promote the charge transfer and expose more electrochemical active sites, which eventually accelerate the reaction kinetics. Thus, the synthesized Ir-NCNFs catalyst exhibits admirable HER activities in both alkaline and acidic conditions with overpotentials of only 23 and 8 mV, which are even superior or close to the benchmark Pt/C catalyst. Furthermore, the synthesized Ir-NCNFs catalyst also exhibits a long-term durability. This study affords a reliable means to construct high-performance supported ultrafine metal nanocatalysts for electrocatalytic applications to alleviate the growing demand for energy conversion.

Locking Effect in Metal@MOF with Superior Stability for Highly Chemoselective Catalysis

Ultrasmall metal nanoparticles (NPs) show high catalytic activity in heterogeneous catalysis but are prone to reunion and loss during the catalytic process, resulting in low chemoselectivity and poor efficiency. Herein, a locking effect strategy is proposed to synthesize high-loading and ultrafine metal NPs in metal-organic frameworks (MOFs) for efficient chemoselective catalysis with high stability. Briefly, the MOF ZIF-90 with aldehyde groups cooperating with diamine chains via aldimine condensation was interlocked, which was employed to confine in situ formation of Au NPs, denoted as Au@L-ZIF-90. The optimized Au@La-ZIF-90 has highly dispersed Au NPs (2.60 ± 0.81 nm) with a loading amount around 22 wt % and shows a great performance toward 3-aminophenylacetylene (3-APA) from the selective hydrogenation of 3-nitrophenylacetylene (3-NPA) with a high yield (99%) and excellent durability (over 20 cycles), far superior to contrast catalysts without chains locking and other reported catalysts. In addition, experimental characterization and systematic density functional theory calculations further demonstrate that the locked MOF modulates the charge of Au nanoparticles, making them highly specific for nitro group hydrogenation to obtain 3-APA with high selectivity (99%). Furthermore, this locking effect strategy is also applicable to other metal nanoparticles confined in a variety of MOFs, and all of these catalysts locked with chains show great selectivity (≥90%) of 3-APA. The proposed strategy in this work provides a novel and universal method for precise control of the inherent activity of accessible metal nanoparticles with a programmable MOF microenvironment toward highly specific catalysis.

Water-soluble ionic carbon nitride as unconventional stabilizer for highly catalytically active ultrafine gold nanoparticles.

Ultrafine metal nanoparticles (NPs) hold promise for applications in many fields, including catalysis. However, ultrasmall NPs are typically prone to aggregation, which often leads to performance losses, such as severe deactivation in catalysis. Conventional stabilization strategies (e.g., immobilization, embedding, or surface modification by capping agents) are typically only partly effective and often lead to loss of catalytic activity. Herein, a novel type of stabilizers based on water-soluble ionic (K+ and Na+ containing) polymeric carbon nitride (i.e., K,Na-poly(heptazine imide) = K,Na-PHI) is reported that enables effective stabilization of highly catalytically active ultrafine (size of ∼2-3 nm) gold NPs. Experimental and theoretical comparative studies using different structural units of K,Na-PHI (i.e., cyanurate, melonate, cyamelurate) indicate that the presence of functionalized heptazine moieties is crucial for the synthesis and stabilization of small Au NPs. The K,Na-PHI-stabilized Au NPs exhibit remarkable dispersibility and outstanding stability even in solutions of high ionic strength, which is ascribed to more effective charge delocalization in the large heptazine units, resulting in more effective electrostatic stabilization of Au NPs. The outstanding catalytic performance of Au NPs stabilized by K,Na-PHI is demonstrated using the selective reduction of 4-nitrophenol to 4-aminophenol by NaBH4 as a model reaction, in which they outperform even the benchmark "naked" Au NPs electrostatically stabilized by excess NaBH4. This work thus establishes ionic carbon nitrides (PHI) as alternative capping agents enabling effective stabilization without compromising surface catalysis, and opens up a route for further developments in utilizing PHI-based stabilizers for the synthesis of high-performance nanocatalysts.

Spontaneous Phase Segregation Enabling Clogging Aversion in Continuous Flow Microfluidic Synthesis of Nanocrystals Supported on Reduced Graphene Oxide

Eliminating clogging in capillary tube reactors is critical but challenging for enabling continuous-flow microfluidic synthesis of nanoparticles. Creating immiscible segments in a microfluidic flow is a promising approach to maintaining a continuous flow in the microfluidic channel because the segments with low surface energy do not adsorb onto the internal wall of the microchannel. Herein we report the spontaneous self-agglomeration of reduced graphene oxide (rGO) nanosheets in polyol flow, which arises because the reduction of graphene oxide (GO) nanosheets by hot polyol changes the nanosheets from hydrophilic to hydrophobic. The agglomerated rGO nanosheets form immiscible solid segments in the polyol flow, realizing the liquid-solid segmented flow to enable clogging aversion in continuous-flow microfluidic synthesis. Simultaneous reduction of precursor species in hot polyol deposits nanocrystals uniformly dispersed on the rGO nanosheets even without surfactant. Cuprous oxide (Cu2O) nanocubes of varying edge lengths and ultrafine metal nanoparticles of platinum (Pt) and palladium (Pd) dispersed on rGO nanosheets have been continuously synthesized using the liquid-solid segmented flow microfluidic method, shedding light on the promise of microfluidic reactors in synthesizing functional nanomaterials.

Ultrafine metallic cobalt nanoparticle encapsulated in N‐doped carbon as high‐efficiency catalysts for reduction of 4‐nitrophenol

Novel and efficient ultrafine metallic cobalt nanoparticles encapsulated in N‐doped carbon catalysts are prepared via a facile method from pyrolysis of ZIF‐67‐x%CTAB, which is modified by CTAB (cetyltrimethyl ammonium bromide). The content of surfactant CTAB can control the crystal size of ZIF‐67, which further determines the Co particle size of Co@CN‐x%CTAB. The as‐prepared ZIF‐67‐x%CTAB and Co@CN‐x%CTAB were characterized by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), high‐resolution transmission electron microscopy (HRTEM), Brunauer−Emmett−Teller (BET), and X‐ray photoelectron spectroscopy (XPS). Co@CN‐0%CTAB could not maintain the primary morphologies of ZIF‐67‐0%CTAB with the collapse of skeleton. However, the Co@CN‐3%CTAB and Co@CN‐5%CTAB catalysts inherit the original morphologies with skeleton constriction. It indicated that Co@CN catalysts could maintain the skeleton structure of ZIF‐67 by adding CTAB during the preparation process. The particle size of Co@CN decreased with the increasing of CTAB content. Moreover, the addition of CTAB facilitated the formation of Co‐Nx species on catalyst surface. The kinetic rate constant of Co@CN‐5%CTAB catalyst was 0.99 min−1, which is 2.5 times as high as that of Co@CN‐0%CTAB catalyst for 4‐nitrophenol reduction. The excellent catalytic performance of Co@CN‐5%CTAB may be due to the presence of Co (0) species generated in situ during the calcination process, the smaller Co nanoparticles and more Co‐Nx site on the surface of the catalyst.

Nanostructured hexagonal BN coating-supported silver and iron oxide nanoparticles and related bactericidal and fungicidal activities

The history of mankind is inextricably linked with the fight against infections, and today this problem is even more urgent. To address this important issue, we deposited h-BN coatings decorated with ultrafine metallic silver or iron oxide nanoparticles (NPs). The coatings release metal ions in a concentration dependent manner. Fe/h-BN coatings at a minimum inhibitory concentration (MIC) of iron oxide NPs (74 µg/cm2), effectively suppress the growth of Escherichia coli K-261 and U20, Staphylococcus aureus MW2 and 839, and Streptococcus pneumoniae ATCC33400 bacterial strains and Candida parapsilosis ATCC90018 fungus after 24 h. Enhanced bactericidal and fungicidal activities of Fe-rich samples is attributed to generation of high amount of ROS. Ag/h-BN materials at MIC of Ag equal to 12 µg/cm2, completely inactivate Escherichia coli K-261 and U20, and Staphylococcus aureus MW2 and 839 strains after 24 h. Sample with 25 μg/cm2 of Ag NPs kill all Escherichia coli K-261 and U20, and Staphylococcus aureus MW2 cells after 3 h and effectively inhibit the growth of Staphylococcus aureus ATCC25923, Candida parapsilosis ATCC90018, Escherichia coli C600, Candida auris CBS10913, and Streptococcus pneumoniae ATCC33400. These results are important for the further development of nanostructured films with a wide spectrum of activity against various pathogens.

Ultrafine Ru nanoparticles confined in graphene-doped porous g-C3N4 for effectively boosting ammonia borane hydrolysis

Ammonia borane (AB) hydrolysis is a promising strategy for the development of hydrogen energy, and ultrafine metal nanoparticles (NPs) are attractive catalysts owing to their abundant active sites. In this work, porous graphitic carbon nitride (CN) are doped with reduced graphene oxide (rGO) and used as supports to evenly confine ultrafine Ru NPs with an adsorption-chemical reduction method. The results show that the different assembly methods and compositions affect the geometric and electronic characteristics of the composites, thus affecting the catalytic behavior in AB hydrolysis. Also, the effects of different Ru loadings and NaOH dosages are researched to improve the hydrolysis efficiency. Specifically, the optimal Ru/CN-rGO catalysts display exciting catalytic performance due to the proper porous structure, N, O co-doping and highly dispersed ultrafine Ru NPs. The corresponding turnover frequency (887.2 min−1) in the presence of NaOH (1.00 mol L−1) and the apparent activation energy (21.7 kJ mol−1) are superior to many previous results. The facile fabrication strategy and robust performance attest to a promising potential for Ru/CN-rGO in the fields of hydrogen energy.

Ultrafine gold nanoparticles dispersed in conjugated microporous polymers with sulfhydryl functional groups to improve the reducing activity of 4-nitrophenol

Achieving the preparation of uniformly loaded ultrafine metal nanoparticles catalysts is a key problem in the field of catalysis. In this study, ultrafine gold nanoparticle catalysts were prepared by using conjugated microporous polymers (CMPs) modified with sulfhydryl group to support gold. High-resolution transmission electron microscopy (HR-TEM) at Au@TBD-S-SH showed that the average particle size of gold nanoparticles (Au NPs) was 3.4 nm. The higher catalytic activity was shown by comparing the normalized reaction rate constants (Knor = 117) from the work of other investigators. Moreover, the catalysts maintained their activity after ten cycles. Meanwhile, Au NPs increased in size probably on account of adsorption products and slight agglomeration. These studies demonstrated that functionalized CMPs loaded with noble metals can efficiently remove phenolic compounds from wastewater.

Ru nanoparticles anchored on porous N-doped carbon nanospheres for efficient catalytic hydrogenation of Levulinic acid to γ-valerolactone under solvent-free conditions

The catalytic transformation of the biomass platform compound levulinic acid (LA) to γ-valerolactone (GVL) is a vital reaction to produce related renewable chemicals and fuels. Developing stable catalysts with highly dispersed and accessible ultrafine metal nanoparticle (NP) active sites for the hydrogenation of LA under solvent-free conditions is still a major challenge. Herein, a versatile nano-emulsion self-assembly method was employed to fabricate N-doped carbon nanospheres with a high specific surface area and hierarchically porous structure. Ultrafine Ru NPs were successfully anchored on the hierarchal porous N-doped carbon nanospheres (HPNC) with high dispersion. The obtained Ru/HPNC catalyst exhibited excellent catalytic performance for LA hydrogenation to GVL under solvent-free conditions with outstanding reusability. In contrast, Ru NPs embedded in other supports (including activated carbon and carbon nanotubes) were observed to be less effective under the same reaction conditions. The superior catalytic performance of the Ru/HPNC catalyst is due to the hierarchically porous catalyst structure, and accessible ultrafine Ru active sites which can promote the activation of CO bonds and H2 absorption during the catalytic process. The reaction pathway of LA hydrogenation to GVL is clearly researched by theoretical calculations. Thus, the current work provides a facile strategy for the synthesis of highly dispersed ultrafine metal NP-based catalysts for an important biomass transformation.

H2 Plasma Reducing Ni Nanoparticles for Superior Catalysis on Hydrogen Sorption of MgH2

Highly fine, dispersive, and active catalysts are essential for lowering the operating temperature of MgH2, a promising high-capacity material for solid-state hydrogen storage. In this work, ultrafine Ni nanoparticles (2–6 nm) are synthesized from the precursor nickel acetylacetonate (C10H14NiO4) on the surface of MgH2 by H2 plasma reduction process, followed by further ball milling. The obtained composite could rapidly release more than 6.5 wt % H within 10 min at 275 °C. Even at a low temperature of 225 °C, up to 6 wt % H could be desorbed. The MgH2–Ni composite also exhibits excellent low-temperature hydrogenation kinetics and almost no capacity degradation over nine hydrogenation/dehydrogenation cycles. The significant improvement in the hydrogen-storage properties is attributed to the in situ formation of ultrafine and stable Mg2NiH0.3 nanocrystals during cycling. This work provides a convenient approach to synthesize ultrafine metal nanoparticles for catalytic applications in the field of high energy storage density hydride materials.

From ammonium Hexahalorhenates(IV) to nanocrystalline rhenium metal: A combined thermal, diffraction and microscopic analysis

Rhenium metal powder is a material of industrial importance. Several industrial and laboratory methods have been developed for the preparation of ultrafine Re metal powder and nanoparticles. The present study provides a better understanding of the characteristic and formation of Re metal powder from the decomposition of (NH4)2ReX6 salt (X = F, Cl, Br, I) at high temperature in inert atmosphere. Such analysis resulted in the formation of nanocrystalline Re metal as characterized by powder XRD. Williamson-Hall, Scherrer, and Williamson-Smallman methods were employed to study the effect of crystallize size, lattice strain, and dislocation density as analyzed from powder XRD peak broadening. The morphology and composition of the metal were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy.

Preparation Strategy Using Pre-Nucleation Coupled with In Situ Reduction for a High-Performance Catalyst towards Selective Hydrogen Production from Formic Acid

Formic acid decomposition (FAD) is one of the most promising routes for rapid hydrogen (H2) production. Extensive efforts have been taken to develop efficient catalysts, which calls for the simultaneous regulation of the electronic structure and particle size of the catalyst. The former factor determines the intrinsic performance, while the latter corresponds to the active site utilization. Here, an effective preparation strategy, pre-nucleation coupled with in situ reduction, is developed to realize and well-tune both surface electronic states and particle size of the pallidum (Pd) catalyst. Benefiting from the structural merits, the as-prepared catalyst exhibits high mass-specific activity of 8.94 molH2/(gPd·h) with few carbon monoxide (CO) molecules, and the activation energy could reach a value as small as 33.1 kJ/mol. The work not only affords a highly competitive FAD catalyst but also paves a new avenue to the synthesis of ultra-fine metal nanoparticles with tailorable electronic structures.

Confinement synthesis in porous molecule-based materials: a new opportunity for ultrafine nanostructures.

A balance between activity and stability is greatly challenging in designing efficient metal nanoparticles (MNPs) for heterogeneous catalysis. Generally, reducing the size of MNPs to the atomic scale can provide high atom utilization, abundant active sites, and special electronic/band structures, for vastly enhancing their catalytic activity. Nevertheless, due to the dramatically increased surface free energy, such ultrafine nanostructures often suffer from severe aggregation and/or structural degradation during synthesis and catalysis, greatly weakening their reactivities, selectivities and stabilities. Porous molecule-based materials (PMMs), mainly including metal–organic frameworks (MOFs), covalent organic frameworks (COFs) and porous organic polymers (POPs) or cages (POCs), exhibit high specific surface areas, high porosity, and tunable molecular confined space, being promising carriers or precursors to construct ultrafine nanostructures. The confinement effects of their nano/sub-nanopores or specific binding sites can not only effectively limit the agglomeration and growth of MNPs during reduction or pyrolysis processes, but also stabilize the resultant ultrafine nanostructures and modulate their electronic structures and stereochemistry in catalysis. In this review, we highlight the latest advancements in the confinement synthesis in PMMs for constructing atomic-scale nanostructures, such as ultrafine MNPs, nanoclusters, and single atoms. Firstly, we illustrated the typical confinement methods for synthesis. Secondly, we discussed different confinement strategies, including PMM-confinement strategy and PMM-confinement pyrolysis strategy, for synthesizing ultrafine nanostructures. Finally, we put forward the challenges and new opportunities for further applications of confinement synthesis in PMMs.

SiO2-Coated Ag Nanoparticles for Conversion of Terminal Alkynes to Propolic Acids via CO2 Insertion

Integration of adequate activity, stability, and productivity in a catalyst is of strategical importance to achieve high performance, particularly for inactive reactants, e.g., CO2. Here, using a reversed microemulsion method, ultrafine metallic Ag nanoparticles coated with porous SiO2 can be facilely obtained using micelles as separated nanoreactors for the preparation. Such architectures allowed the rigid SiO2 matrices to act as physical spacers, so that aggregation of the Ag particles could be avoided. Meanwhile, due to the templating effect from the surfactant, large mesopores could be induced in the SiO2 shell, and thus the diffusion barrier of reactants could be minimized. When used as a heterogeneous catalyst for carboxylation of terminal alkynes by CO2 under mild conditions, the prepared x[email protected]2 catalysts showed extraordinary performance in terms of excellent activity, stability, productivity, and wide substrate scope. The knowledge developed here may also enrich the toolbox for performance promotion of metal catalysts via specially fabricated structures.

Ultra-Fine Gold Nanoparticles Enabled Au-BST NF/PVTC Composites to Have Excellent Energy Storage Performance

Composites composed of a polymer matrix and inorganic fillers have attracted tremendous attention owing to their promising application in flexible dielectric film capacitors. However, boosting the energy density while ensuring a high charging-discharging efficiency is still a huge challenge. In this work, Ba0.6Sr0.4TiO3 nanofibers (BST NFs) doped with different contents of ultra-fine Au nanoparticles are precisely prepared by one-step electrospinning, and P(VDF-TrFE-CFE) (PVTC)-based composites incorporated with various nanofibers are further prepared via a solution-casting process. A superior discharged energy density of 14.2 J/cm3 and an excellent energy storage efficiency of 71.3% have been achieved in such monolayer composites by optimizing the doping content and distribution of ultra-fine Au nanoparticles in BST NFs, which are induced by enhanced electric displacement and ensure suppressed energy loss and improved electric breakdown strength. Hence, doping moderate ultra-fine metal nanoparticles in one-dimensional inorganic nanofillers is a feasible strategy for designing polymer-based composites with outstanding performance.