Preparation and characterization of novel polyoxometalate/CoFe2O4/metal–organic framework magnetic core–shell nanocomposites for the rapid removal of organic dyes from water

In this study, the MIL-101(Cr) metal–organic framework was functionalized with a Dowson-type polyoxometalate (P₂W₁₈O₆₂⁶⁻; POM) and magnetic spinel cobalt ferrite (CoFe₂O₄; CFO) through a hydrothermal route and was characterized by means of FT-IR, XRD, FE-SEM, EDX, BET, and VSM measurements. All analyses confirmed the successful encapsulation of POM (∼32.2 wt%) into the magnetic MIL-101(Cr) framework. Compared to the pristine MIL-101(Cr) MOF, the as-prepared magnetic ternary nanocomposite (abbreviated as POM/CFO/MIL-101(Cr)) demonstrated a notable decrease in both the surface area and pore volume because of the incorporation of CoFe₂O₄ nanoparticles and huge P₂W₁₈O₆₂⁶⁻ polyanions into the cages of the MIL-101(Cr) framework. The POM/CFO/MIL-101(Cr) was then applied as a magnetically separable adsorbent for the rapid elimination of rhodamine B (RhB), methyl orange (MO), and methylene blue (MB) dye pollutants from aqueous solutions. For achieving the optimized conditions, the effects of initial pH, initial dye concentration, temperature, salt effect, and adsorbent dose on MB and RhB elimination were investigated. The dye adsorption isotherms followed the Langmuir model and pseudo-second-order kinetic model. The POM/CFO/MIL-101(Cr) composite material not only exhibited a fast adsorption rate towards dye molecules, but also demonstrated the selective adsorption of the cationic dyes in wastewater. The recycling experiments also demonstrated that the POM/CFO/MIL-101(Cr) adsorbent was highly stable and could be quickly recovered under a magnetic field without any alteration in the structure. The high adsorption capacity, simple fabrication method, rapid separation by a magnet and supreme reusability of the POM/CFO/MIL-101(Cr) nanocomposite make it an attractive adsorbent for the elimination of cationic dyes from wastewater.

The magnetic CoFe₂O₄/MIL-101 (Cr) metal–organic framework nanocomposite containing P₂W₁₈O₆₂⁶⁻ polyoxometalate was fabricated and applied as an ultrafast adsorbent to remove organic dyes from water.     

Magnetic–plasmonic Ni@Au core–shell nanoparticle arrays and their SERS properties

In this paper, large-area magnetic–plasmonic Ni@Au core–shell nanoparticle arrays (NPAs) with tunable compositions were successfully fabricated by a direct laser interference ablation (DLIA) incorporated with thermal dewetting method. The magnetic properties of the Ni@Au core–shell NPAs were analyzed and the saturation magnetization (M_s) of the Ni₈₀@Au₂₀ nanoparticles was found to be higher than that of nickel-only nanoparticles with the same diameter. Using Rhodamine 6G (R6G) as a Raman reporter molecule, the surface enhanced Raman scattering (SERS) property of the Ni@Au core–shell NPAs with a grain size distribution of 48 ± 42 nm and a short-distance order of about 200 nm was examined. A SERS enhancement factor of 2.5 × 10⁶ was realized on the Ni₅₀@Au₅₀ NPA substrate, which was 9 times higher than that for Au nanoparticles with the same size distribution. This was due to the enhanced local surface plasmon resonance (LSPR) between the ferromagnetic Ni cores and the surface polariton of the Au shells of each nanoparticle. The fabrication of the Ni@Au core–shell NPAs with different compositions offers a new avenue to tailor the optical and magnetic properties of the nanostructured films for chemical and diagnostic applications.

In this paper, large-area magnetic–plasmonic Ni@Au core–shell nanoparticle arrays (NPAs) with tunable compositions were successfully fabricated by a direct laser interference ablation (DLIA) incorporated with thermal dewetting method.     

Synthesis and photoluminescence properties of hybrid 1D core–shell structured nanocomposites based on ZnO/polydopamine

In the present work, we report on the modelling of processes at the zinc oxide and polydopamine (ZnO/PDA) interface. The PDA layer was deposited onto ZnO nanorods (NRs) via chemical bath deposition. The defect concentrations in ZnO before and after PDA deposition were calculated and analysed. The ZnONRs/PDA core–shell nanostructures were studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman and Fourier-transform infrared (FTIR) spectroscopy, photoluminescence (PL) measurements, and diffuse reflectance spectroscopy. The TEM and electron energy loss spectroscopy (EELS) measurements confirmed the conformal coating of PDA, while the PL emission from ZnO and ZnONRs/PDA samples showed a reduction of intensity after the PDA deposition. The decrease of defect concentration participating in PL and quantum efficiency explains the PL reduction. Finally, the observed decrease of activation energies and a shift of the PL peaks are attributed to the formation of an additional local electrical field between the PDA and ZnO nanostructures.

The results shown in this study provide a unique insight into the optical and electronic processes of the ZnO/PDA interface.     

Double-exponential refractive index sensitivity of metal–semiconductor core–shell nanoparticles: the effects of dual-plasmon resonances and red-shift

In order to improve the refractive index sensitivity of a localized surface plasmon resonance (LSPR) sensor, we present a new type of LSPR sensor whose refractive index sensitivity can be improved by greatly increasing the plasmon wavelength red-shift of metal–semiconductor core–shell nanoparticles (CSNs). Using extended Mie theory and Au@Cu_2−xS CSNs, we theoretically investigate the optical properties of metal–semiconductor CSNs in the entire near-infrared band. Compared with dielectric–metal and metal–metal CSNs under the same conditions, the metal–semiconductor CSNs have a higher double-exponential sensitivity curve because their core and shell respectively support two LSPRs that greatly increase the LSPR red-shift to the entire near-infrared range. It is worth noting that the sensitivity can be improved effectively by increasing the ratio of the shell-thickness to core-radius, instead of decreasing it in the case of the dielectric–metal CSNs. The underlying reason for the enhancement of sensitivity is the increase of repulsive force with the enlargement of shell thickness, which is different from the dielectric–metal CSNs. This design method not only paves the way for utilizing metal–semiconductor CSNs in biology and chemistry, but also proposes new ideas for the design of sensors with high sensitivity.

We present a new type of localized surface plasmon resonance (LSPR) sensor whose refractive index sensitivity can be improved by greatly increasing the plasmon wavelength red-shift of metal–semiconductor core–shell nanoparticles (CSNs).     

Silicone/Ag@SiO2 core–shell nanocomposite as a self-cleaning antifouling coating material

The effects of Ag@SiO₂ core–shell nanofiller dispersion and micro-nano binary structure on the self-cleaning and fouling release (FR) in the modelled silicone nano-paints were studied. An ultrahydrophobic polydimethylsiloxane/Ag@SiO₂ core–shell nanocomposite was prepared as an antifouling coating material. Ag@SiO₂ core–shell nanospheres with 60 nm average size and a preferential {111} growth direction were prepared via a facile solvothermal and a modified Stöber methods with a controlled shell thickness. Ag@SiO₂ core–shell nanofillers were inserted in the silicone composite surface via solution casting technique. A simple hydrosilation curing mechanism was used to cure the surface coating. Different concentrations of nanofillers were incorporated in the PDMS matrix for studying the structure–property relationship. Water contact angle (WCA) and surface free energy determinations as well as atomic force microscopy and scanning electron microscope were used to investigate the surface self-cleaning properties of the nanocomposites. Mechanical and physical properties were assessed as durability parameters. A comparable study was carried out between silicone/spherical Ag@SiO₂ core–shell nanocomposites and other commercial FR coatings. Selected micro-foulants were used for biological and antifouling assessments up to 28 days. Well-distributed Ag@SiO₂ core–shell (0.5 wt%) exhibited the preferable self-cleaning with WCA of 156° and surface free energy of 11.15 mN m⁻¹.

The effects of Ag@SiO₂ core–shell nanofiller dispersion and micro-nano binary structure on the fouling release of silicone paints were studied. An ultrahydrophobic PDMS/Ag@SiO₂ core–shell nanocomposite was prepared as an antifouling coating material.     

Understanding metal-enhanced fluorescence and structural properties in Au@Ag core–shell nanocubes

Au@Ag core–shell structures have received particular interest due to their localized surface plasmon resonance properties and great potential as oxygen reduction reaction catalysts and building blocks for self-assembly. In this study, Au@Ag core–shell nanocubes (Au@AgNCs) were fabricated in a facile manner via stepwise Ag reduction on Au nanoparticles (AuNPs). The size of the Au@AgNCs and their optical properties can be simply modulated by changing the Ag shell thickness. Structural characterization has been carried out by TEM, SAED, and XRD. The metal-induced fluorescence properties of probe molecules near the Au@AgNCs were measured during sedimentation of the Au@AgNCs. The unique ring-like building block of Au@AgNCs has dual optical functions as a fluorescence quencher or fluorescence enhancement medium depending on the assembled regions.

The unique ring-like building block of Au@AgNCs has dual optical functions as a fluorescence quencher and fluorescence enhancement medium.     

Rational design of asymmetric supercapacitors via a hierarchical core–shell nanocomposite cathode and biochar anode

Hierarchical MnO₂ nanosheets attached on hollow NiO microspheres have been designed by a facile hydrothermal process. The core–shell structure is achieved by decorating an MnO₂ nanosheet shell on a hollow NiO sphere core. The highly hollow and porous structure exhibits a high surface area, shortened ion diffusion length, outstanding electrochemical properties (558 F g⁻¹ at a current density of 5 mA cm⁻²), and excellent cycling stability (83% retention after 5000 cycles). To further evaluate the NiO/MnO₂ core–shell composite electrode for real applications, three asymmetric supercapacitors (NiO/MnO₂//pomelo peel (PPC), NiO/MnO₂//buckwheat hull (BHC), and NiO/MnO₂//activated carbon (AC)) are assembled. The results demonstrated that NiO/MnO₂//BHC delivered a substantial energy density (20.37 W h kg⁻¹ at a power density of 133.3 W kg⁻¹) and high cycling stability (88% retention after 5000 cycles) within a broad operating potential window of 1.6 V.

Hierarchical MnO₂ nanosheets standing on hollow NiO microspheres have been designed by a facile hydrothermal process. Furthermore, asymmetric supercapacitors via core/shell NiO/MnO₂ cathode and biochar anode were assembled.     

Preparation of biomimetic non-iridescent structural color based on polystyrene–polycaffeic acid core–shell nanospheres

Caffeic acid (CA), as a natural plant-derived polyphenol, has been widely used in surface coating technology in recent years due to its excellent properties. In this work, caffeic acid was introduced into the preparation of photonic band gap materials. By controlling the variables, a reasonable preparation method of polystyrene (PS) @polycaffeic (PCA)–Cu(ii) core–shell microspheres was achieved: 1 mmol L⁻¹ cupric chloride anhydrous (CuCl₂), 3 mmol L⁻¹ sodium perborate tetrahydrate (NaBO₃·4H₂O), 2 mmol L⁻¹ CA and 2 g L⁻¹ polystyrene (PS) were reacted at 50 °C for 10 min to prepare PS@PCA–Cu(ii) core–shell microspheres through rapid oxidative polymerization of CA coated PS of different particle diameters. The amorphous photonic crystal structure was self-assembled through thermal assisted-gravity sedimentation, resulting in structural color nanomaterials with soft and uniform color, no angle dependence, stable mechanical fastness and excellent UV resistance.

Caffeic acid (CA), as a natural plant-derived polyphenol, has been widely used in surface coating technology in recent years due to its excellent properties.     

Chemically activated core–shell structured IF-WS2@C nanoparticles enhance sugarcane-based carbon/epoxy nanocomposites

Ternary composites have demonstrated better capability than binary composites in enhancing the mechanical properties of the modified epoxy resins and are, therefore, currently under intensive investigation. Herein, we report a novel ternary nanocomposite prepared by filling a binary BPF (bisphenol F epoxy resin)/SCPs (sugarcane-based carbon powders) matrix with C-coated inorganic fullerene-like tungsten disulfide (IF-WS₂@C) nanoparticles, and the analysis of its interface synergetic effect using XPS/FTIR. This activated nano-carbon core–shell structure filler is considered an ideal nanofiller and shows the excellent mechanical performance of the ternary composites. XRD, IR, XPS, SEM, and TEM characterizations were applied in investigating this nanocomposite. The improvement of the thermal and mechanical properties demonstrated the enhancement effects of this nanofiller. The results show that the great improvement of the bending modulus of 39.4% increased with the addition of 0.5 wt% IF-WS₂@C nanoparticles, while 34.1% enhancement of bending strength was obtained with the addition of 0.2 wt% IF-WS₂@C nanoparticles. The hardness and thermal conductivity were also boosted up to 5.2% and 33.1% with 0.5 wt% addition, respectively. The incorporation of a chemically activated coating may provide a novel means for improving graphite crystallization, which could somehow expand the potential application of IF-WS₂@C nanoparticles.

Schematic diagram and typical curing mechanism of epoxy resins and the unique interactions of the IF-WS₂@C nanoparticles introduced into the matrix.     

Co(OH)F nanorods@KxMnO2 nanosheet core–shell structured arrays for pseudocapacitor application

In this work, Co(OH)F nanorods@K_xMnO₂ nanosheet core–shell nanostructure was assembled on Ni foam by a facile hydrothermal method and incorporated with an electrodeposition process. Benefiting from their core–shell nanostructure and heterogeneous nanocomposites, the arrays present high areal capacitance up to 1046 mF cm⁻² at 1 mA cm⁻² and display a remarkable specific capacitance retention of 118% after 3000 cycles. When the current density increases to 10 mA cm⁻², the capacitance is 821 mF cm⁻² displaying a good rate capability. The excellent electrochemical properties allow them to be used as a promising electrode material for pseudocapacitors and display wide application potential in the field of electrochemical capacitors.

In this work, Co(OH)F nanorods@K_xMnO₂ nanosheet core–shell nanostructure was assembled on Ni foam by a facile hydrothermal method and incorporated with an electrodeposition process.     

Hollow core–shell structured TS-1@S-1 as an efficient catalyst for alkene epoxidation

Hollow core–shell structured TS-1@S-1 zeolite (HCS-TS) was prepared successfully for the first time, which exhibited excellent activity in the epoxidation of alkenes. Combining TEM, UV-vis, UV-Raman, pyridine-IR, solid-state MAS NMR, XPS and so on characterization, the improvement in the catalytic performance of hollow core–shell structured TS-1@S-1 zeolite was credited to the newly formed superior active sites: defective Ti(OSi)₃(OH) species in HCS-TS and six-coordinated titanium active species in uncalcined HCS-TS (HCS-TS^P). Interestingly, these two different titanium active species in the samples could be constructed through calcination or not in the same synthesis process. A possible formation mechanism was investigated in detail; it indicated that the hollowing treatment of TS-1 in the first step was conducive to the construction of the new superior active sites in the samples, and there was a synergistic effect on the formation of these active sites between TPAOH and TEOS in the second step of the synthesis process. This strategy is feasible to enhance the catalytic performance of TS-1, and is suitable for the synthesis of TS-1 on an industrial scale.

Hollow core–shell structured TS-1@S-1 with high catalytic performance was synthesized successfully owing to the formation of different titanium active centers.     

Preparation of MoS2-based polydopamine-modified core–shell nanocomposites with elevated adsorption performances

New molybdenum disulfide (MoS₂)-based core–shell nanocomposite materials were successfully prepared through the self-assembly of mussel-inspired chemistry. Characterization by Fourier transform infrared, thermogravimetric analysis, scanning electron microscope and transmission electron microscopy revealed that the surface of the flaked MoS₂ was homogeneously coated with a thin layer of polydopamine (PDA). Dye adsorption performances of the synthesized MoS₂–PDA nanocomposites were investigated at different pH values and reaction times. Compared with pure MoS₂ nanosheets, the obtained core–shell nanocomposites showed elevated adsorption performances and high stability, indicating their potential applications in wastewater treatment and composite materials.

New core–shell MoS₂–PDA nanocomposites are prepared via mussel-inspired chemistry and a simple interfacial self-assembly process, demonstrating potential applications in wastewater treatment and self-assembled core–shell composite materials.     

Preparation and lithium storage of core–shell honeycomb-like Co3O4@C microspheres

Core–shell honeycomb-like Co₃O₄@C microspheres were synthesized via a facile solvothermal method and subsequent annealing treatment under an argon atmosphere. Owing to the core–shell honeycomb-like structure, a long cycling life was achieved (a high reversible specific capacity of 318.9 mA h g⁻¹ was maintained at 5C after 1000 cycles). Benefiting from the coated carbon layers, excellent rate capability was realized (a reversible specific capacity as high as 332.6 mA h g⁻¹ was still retained at 10C). The design of core–shell honeycomb-like microspheres provides a new idea for the development of anode materials for high-performance lithium-ion batteries.

The reversible specific capacity of CSHCo₃O₄@C microspheres was as high as 332.6 mA h g⁻¹ at 10C, which was significantly higher than that of SCo₃O₄ microspheres (68.7 mA h g⁻¹).     

CNT–TiO2 core–shell structure: synthesis and photoelectrochemical characterization

Porous composite coatings, made of a carbon nanotube (CNT)–TiO₂ core–shell structure, were synthesized by the hybrid CVD-ALD process. The resulting TiO₂ shell features an anatase crystalline structure that covers uniformly the surface of the CNTs. These composite coatings were investigated as photoanodes for the photo-electrochemical (PEC) water splitting reaction. The CNT–TiO₂ core–shell configuration outperforms the bare TiO₂ films obtained using the same process regardless of the deposited anatase thickness. The improvement factor, exceeding 400% in photocurrent featuring a core–shell structure, was attributed to the enhancement of the interface area with the electrolyte and the electrons fast withdrawal. The estimation of the photo-electrochemically effective surface area reveals that the strong absorption properties of CNT severely limit the light penetration depth in the CNT–TiO₂ system.

CNT–TiO₂ core–shell nanostructured coatings were made using a hybrid CVD/ALD process. The evaluation of these films as photoanodes for the photoelectrochemical water splitting reaction reveals a clear benefit from the involvement of CNTs.     

Microfluidics for core–shell drug carrier particles – a review

Core–shell drug-carrier particles are known for their unique features. Due to the combination of superior properties not exhibited by the individual components, core–shell particles have gained a lot of interest. The structures could integrate core and shell characteristics and properties. These particles were designed for controlled drug release in the desired location. Therefore, the side effects would be minimized. So, these particles'' advantages have led to the introduction of new methods and ideas for their fabrication. In the past few years, the generation of drug carrier core–shell particles in microfluidic chips has attracted much attention. This method makes it possible to produce particles at nanometer and micrometer levels of the same shape and size; it usually costs less than other methods. The other advantages of using microfluidic techniques compared to conventional bulk methods are integration capability, reproducibility, and higher efficiency. These advantages have created a positive outlook on this approach. This review gives an overview of the various fluidic concepts that are used to generate microparticles or nanoparticles. Also, an overview of traditional and more recent microfluidic devices and their design and structure for the generation of core–shell particles is given. The unique benefits of the microfluidic technique for core–shell drug carrier particle generation are demonstrated.

Microfluidics application for core–shell drug carrier particles synthesis and the advantages of using this technique compared to conventional bulk methods.     

Ionic magnetic core–shell nanoparticles for DNA extraction

Magnetic nanoparticles with specific surface features are interesting materials for biomedical applications. The combination of molecular interactions on small particles with macroscopic cohesion forces offers unique opportunities. This work reports the synthesis of magnetic core–shell nanoparticles with alkylimidazolium coated surface for effective DNA extraction. A magnetic Fe₂O₃ core was coated with a silica shell and functionalized with an organic halide. This enabled a surface coating with organic cations to mediate effective molecular interactions with polyanionic DNA. The large surface area of the ∼20 nm small particles with a magnetization of 25 emu g⁻¹ enabled high DNA particle loading of 1/30 m% with easy isolation based on an external magnetic field. Moreover, the coating of the particles stabilized DNA against ultrasound initiated fragmentation.

The fabrication ionic magnetic core-shell nanoparticles were simple synthesize with a super-ferromagnetic and small particle size properties, which enabled sufficient DNA particle loading with easy isolation based on an external magnetic field.     

One-pot one-step synthesis of Au@SiO2 core–shell nanoparticles and their shell-thickness-dependent fluorescent properties

Herein, we report a one-pot one-step method for the preparation of Au@SiO₂ core–shell nanoparticles (NPs) via a facile heating treatment of an alcoholic-aqueous solution of chloroauric acid (HAuCl₄), 2-methylaminoethanol (2-MAE), cetyltrimethylammonimum bromide (CTAB), and tetraethylorthosilicate (TEOS). The size of the Au core and the thickness of the silica shell can be easily controlled by simply adjusting the volume of HAuCl₄ and TEOS, respectively, which can hardly be achieved by other approaches. The as-prepared Au@SiO₂ core–shell NPs exhibited shell-thickness-dependent fluorescent properties. The optimum fluorescence enhancement of fluorescein isothiocyanate (FITC) was found to occur at a silica shell thickness of 34 nm with an enhancement factor of 5.0. This work provides a new approach for the preparation of Au@SiO₂ core–shell NPs and promotes their potential applications in ultrasensitive analyte detection, theranostics, catalysts and thin-film solar cells.

Au@SiO₂ core–shell nanoparticles with tunable Au core size and silica shell thickness were prepared by a facile one-pot one-step method.     

Ru-containing magnetic yolk–shell structured nanocomposite: a powerful,recoverable and highly durable nanocatalyst

A novel method was used to prepare a magnetic phenylene-based periodic mesoporous organosilica nanocomposite with yolk–shell structure (Fe₃O₄@YSPMO). The Fe₃O₄@YSPMO nanomaterial was prepared by using easily accessible pluronic-P123 and cetyltrimethylammonium bromide (CTAB) surfactants under basic conditions. This material was employed for effective immobilization of potassium perruthenate to prepare an Fe₃O₄@YSPMO@Ru nanocatalyst for the aerobic oxidation of alcohols. The physiochemical properties of the designed Fe₃O₄@YSPMO@Ru nanocomposite were studied using PXRD, FT-IR, TGA, SEM, TEM, ICP, VSM and XPS analyses. Fe₃O₄@YSPMO@Ru was effectively employed as a highly recoverable nanocatalyst in the selective aerobic oxidation of alcohols.

Preparation, characterization and catalytic application of a novel yolk–shell structured magnetic mesoporous organosilica nanocomposite are presented.     

Preparation of core–shell catalyst for the tandem reaction of amino compounds with aldehydes

Heterogeneous noble metal-based catalysts with stable, precise structures and high catalytic performance are of great research interest for sustainable catalysis. In this article, we designed a novel core–shell catalyst, Pd@UiO-66-NH₂@mSiO₂, with Pd@UiO-66-NH₂ as the core and mesoporous SiO₂ (mSiO₂) as the shell. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) measurement results demonstrated that the obtained catalyst has an excellent core–shell structure. It can significantly prevent the aggregation of Pd nanoparticles (NPs), as well as the leaching of Pd NPs during the reaction process, owing to the protective effect of mSiO₂. During the tandem reaction of aniline and benzaldehyde to generate secondary amines, the prepared Pd@UiO-66-NH₂@mSiO₂ is highly efficient, due to the strong acid sites provided by UiO-66-NH₂ and the hydrogenation reduction sites provided by Pd NPs. Meanwhile, the Pd@UiO-66-NH₂@mSiO₂ with porous structure can also enhance the mass transfer of reactants to improve the reaction efficiency. Additionally, the prepared catalyst was used to catalyze the series reaction of amino compounds and aldehydes, and the results showed that just 5 mg of the catalyst can convert more than 99% of the reactants within 60 minutes in the presence of 1 atm H₂ at room temperature. Finally, the selectivity and stability of the as-prepared catalyst were also confirmed.

One-pot reductive amination: benzaldehyde and aniline were converted into high-value secondary amines by using a heterogeneous Pd-based core–shell catalyst and H₂ as a hydrogen source.     

Topographical and compositional engineering of core–shell Ni@Pt ORR electro-catalysts

Complex faceted geometries and compositional anisotropy in alloy nanoparticles (NPs) can enhance catalytic performance. We report on the preparation of binary PtNi NPs via a co-thermolytic approach in which we optimize the synthesis variables, which results in significantly improved catalytic performance. We used scanning transmission electron microscopy to characterise the range of morphologies produced, which included spherical and concave cuboidal core–shell structures. Electrocatalytic activity was evaluated using a rotating disc electrode (1600 rpm) in 0.1 M HClO₄; the electrocatalytic performance of these Ni@Pt NPs showed significant (∼11-fold) improvement compared to a commercial Pt/C catalyst. Extended cycling revealed that electrochemical surface area was retained by cuboidal PtNi NPs post 5000 electrochemical cycles (0.05–1.00 V, vs. SHE). This is attributed to the enclosure of Ni atoms by a thick Pt shell, thus limiting Ni dissolution from the alloy structures. The novel synthetic strategy presented here results in a high yield of Ni@Pt NPs which show excellent electro-catalytic activity and useful durability.

Complex faceted geometries and compositional anisotropy in alloy nanoparticles (NPs) can enhance catalytic performance.