Mesoporous metallic cells: design of uniformly sized hollow mesoporous Pt-Ru particles with tunable shell thicknesses

Finely Composition-Tunable Synthesis of Ultrafine Wavy PtRu Nanowires as Effective Electrochemical Sensors for Dopamine Detection

Preparing Pt-based one-dimensional (1D) ultrafine nanowires with abundant structural defects/grain boundaries and exploring their novel applications have attracted great interest in real-world applications. Here we introduce an environmentally friendly, facile aqueous solution approach to directly prepare a series of sub-3.0 nm PtRu ultrafine wavy nanowires. Characterizations show that the PtRu nanowires are alloy polycrystalline structures with abundant structural defects/grain boundaries. We first introduce the as-synthesized PtRu nanowires into electrochemical biosensors for the detection of DA and find that the Pt₇Ru₃ nanowires exhibit excellent electrocatalytic activity to DA with fast response, ultralow limit of detection, and excellent selectivity at a potential of 0.3 V in 0.1 M phosphate buffered solution (pH 7.2). This study shows an effective approach to the development of ultrafine PtRu nanowires as electrocatalysts for electrochemical nonenzymatic dopamine biosensors.

One-pot synthesis of PtRu nanodendrites as efficient catalysts for methanol oxidation reaction

Bimetallic Pt-based nanodendrites are of particular interest in various catalytic applications due to their high surface areas and low densities. Herein, we provide a facile method for one-pot synthesis of PtRu nanodendrites via the co-reduction of Pt and Ru precursors in oleylamine by H₂. The as-fabricated PtRu nanodendrites exhibit superior catalytic activity and durability compared with PtRu nanocrystals (NCs), synthesized under the same reaction conditions, and the commercial Pt/C catalyst towards the methanol oxidation reaction (MOR).

Synthesis, characterization and performance of bifunctional catalysts for the synthesis of menthol from citronellal

TUD-1 based catalysts containing WO₃ and Pt were synthesized and assessed in the conversion of citronellal to menthol. The hydrogenation on Pt is highest for small WO₃ particles, while their agglomeration leads to a decreased interaction and catalytic performance.

Rational design of porous binary Pt-based nanodendrites as efficient catalysts for direct glucose fuel cells over a wide pH range

Porous binary PtPd, AuPt, PtCu, and PtNi nanodendrites prepared by a facile one-step reduction under ultrasonic irradiation at room temperature, exhibited a substantial catalytic activity towards glucose oxidation reaction at different pH values relative to a commercial Pt/C catalyst.

Facile synthesis of hollow dendritic Ag/Pt alloy nanoparticles for enhanced methanol oxidation efficiency

Hollow dendritic Ag/Pt alloy nanoparticles were synthesized by a double template method.

Kinetically Controlled Synthesis of Pt-Based One-Dimensional Hierarchically Porous Nanostructures with Large Mesopores as Highly Efficient ORR Catalysts

Rational design and construction of Pt-based porous nanostructures with large mesopores have triggered significant considerations because of their high surface area and more efficient mass transport. Hydrochloric acid-induced kinetically controlled reduction of metal precursors in the presence of soft template F-127 and hard template tellurium nanowires has been successfully demonstrated to construct one-dimensional hierarchical porous PtCu alloy nanostructures with large mesopores. Moreover, the electrochemical experiments demonstrated that the PtCu hierarchically porous nanostructures synthesized under optimized conditions exhibit enhanced electrocatalytic performance for oxygen reduction reaction in acid media.

Nanoarchitectures for Mesoporous Metals

The field of mesoporous metal nanoarchitectonics offers several advantages which cannot be found elsewhere. These materials have been showcasing impressive enhancements of their electrochemical properties for further implementation, compared to their micro- and macroporous counterparts. Since the last few decades, various methods have been developed to achieve narrow pore size distribution with a tunable porosity and particle morphology. While hard templates offer a reliable and intuitive approach to synthesize mesoporous metals, the complexity of the technique and the use of harmful chemicals pushed several research groups to focus in other directions. For example, soft templates (e.g., lyotropic crystals, micelles assemblies) and solution phase methods (requiring to control reduction reactions) offer more and more possibilities in terms of available compositions and morphologies. Indeed, various metal (Pt, Pd, Au, Ru, etc.) can now be synthesized as dendritic, core@shell, hollow or polyhedral nanoparticles, with single- or multicomponents, alloyed or not, with unprecedented electrochemical activity.

Smart design of hollow AuPt nanospheres with a porous shell as superior electrocatalysts for ethylene glycol oxidation

Hollow AuPt spherical nanoelectrocatalysts for ethylene glycol oxidation were synthesized by a facile and effective method.

Effect of core/shell structured TiO2@C nanowire support on the Pt catalytic performance for methanol electrooxidation

Core/shell structured carbon-coated titania nanowires combine the advantages of structure and material, improving the electrocatalytic performance of Pt-based catalysts.

Preparation of Mesoporous Bimetallic Au-Pt with a Phase-Segregated Heterostructure Using Mesoporous Silica

Mesoporous bimetallic Au-Pt with a phase-segregated heterostructure has been prepared by using mesoporous silica SBA-15 as a template. Au nanoparticles were prepared as a seed metal within the mesopores, and subsequently Pt was deposited, sandwiching the Au seeds. Energy-dispersive X-ray (EDX) spectral mapping showed that the framework of mesoporous bimetallic Au-Pt, prepared by removing the silica template with HF, was composed of Au nanoparticles joined with Pt nanowires. The Au/Pt ratio of the mesoporous bimetallic Au-Pt could be varied by controlling the number of Au deposition cycles. Pre-adsorbed CO (COad) stripping voltammetry of the mesoporous bimetallic Au-Pt showed that the surfaces of the joined bimetallic structure were electrochemically active. This could be attributed to the open framework structure having a high ratio of exposed bimetallic mesopore surfaces. The described preparative approach, involving a mesoporous silica template and stepwise deposition within the mesopores, enables control of the nanostructure of the bimetallic material, which is greatly promising for the further development of synthetic methodologies for bimetallic structures.

One-step synthesis of porous bimetallic PtCu nanocrystals with high electrocatalytic activity for methanol oxidation reaction

The design of porous bimetallic nanocrystals (NCs) is very important for electrochemical energy conversion. Herein, we report an aqueous solution method for one-step fabrication of porous PtCu NCs assembled by spatially interconnected arms in high yield by a simple ultrasonic treatment of the reaction mixture at room temperature. The proposed method, without the need for multi-step synthesis, high temperatures, and organic solvents, shows an obvious advantage of simplicity for the feasible synthesis of bimetallic PtCu NCs with a porous structure. The as-made porous PtCu NCs are highly active and durable catalysts for the methanol oxidation reaction due to their porous structure and bimetallic composition.

Multimetallic Mesoporous Spheres Through Surfactant-Directed Synthesis

Multimetallic mesoporous spheres are successfully synthesized with ultra-large mesopores with the assistance of nonionic triblock copolymer (F127) as a structural directing agent. The kinetically controlled reduction rate of metal species and the concentration of F127 are critical to the formation of the large mesopores.

2D ultrathin core-shell Pd@Pt(monolayer) nanosheets: defect-mediated thin film growth and enhanced oxygen reduction performance

An operational strategy for the synthesis of atomically smooth Pt skin by a defect-mediated thin film growth method is reported. Extended ultrathin core-shell structured d@Pt(monolayer) nanosheets (thickness below 5 nm) exhibit nearly seven-fold enhancement in mass-activity and surprisingly good durability toward oxygen reduction reaction as compared with the commercial Pt/C catalyst.

Hollow ternary PtPdCu nanoparticles: a superior and durable cathodic electrocatalyst

Hollow PtPdCu nanoparticles with a Pt-enriched surface, formed by the dealloying action of acetic acid, exhibit superior durability and catalytic activity toward the ORR.

Hollow alloyed nanoparticles (NPs) represent one kind of promising fuel cell electrocatalyst. However, the formation of single-cavity hollow structures by a dealloying process is quite challenging owing to the random leaching/dissolution of transition metals, surface passivation and the limited diffusion distance of the noble metals. Here we present a facile method to prepare hollow PtPdCu NPs derived from monodisperse alloy NPs by an acetic acid-assisted dealloying process. Here, acetic acid not only acts as a chemical etching agent but also plays an important role in the removal of the residual surfactants for colloidal NPs. Our findings rectify the current knowledge that hollow alloyed NPs cannot be prepared by a dealloying strategy and provide further understanding of the dealloying process in a ternary system. Such unique hollow ternary PtPdCu NPs exhibit outstanding durability and improved catalytic activity toward the oxygen reduction reaction.

Attachment-based growth: building architecturally defined metal nanocolloids particle by particle

This review highlights the principles and recent mechanistic insight into the synthesis of metal nanostructures using nanoparticles as primary building blocks.

One-pot synthesis of Pt hollow spheres and their performance on electrochemical catalysis

The facile synthesis of Pt hollow spheres with variable sizes was achieved using a surfactant with a long hydrophobic tail.

The dual role of micelles as templates and reducing agents for the fabrication of catalytically active hollow silver nanospheres

A simple and efficient protocol for fabrication of colloidal hollow Ag nanospheres of size less than 30 nm using a triblock copolymer in the absence of any reducing agent is reported, which showed excellent catalytic activity in the Baeyer–Villiger oxidation reaction.

Synthesis of hollow mesoporous ruthenium nanoparticles: evaluation of physico-chemical properties and toxicity

Facile synthesis of hollow mesoporous structured Ru-NPs by dual template method, structural characterization and in vitro biophysical and uptake evaluation for biomedical application.

A versatile strategy to construct multifunctional metal oxide@cyanometallate-based coordination polymer heterostructures

We have developed a novel and versatile spatially confined self-assembly strategy to integrate cyanometallate-based coordination polymers with functional metal oxides into well-defined core@shell heterostructures with various structures, compositions, sizes and morphologies.

Copolymer and platinum ion assisted growth of functionalized gold nanonests

Novel Au nanonests with high yield and uniformity were successfully synthesized using P123 as a soft template and a reductant in an ice water bath with and without the presence of the second metallic source of Pt ions.

Ligand-controlled Co-reduction versus electroless Co-deposition: synthesis of nanodendrites with spatially defined bimetallic distributions

The predictable synthesis of bimetallic nanostructures via co-reduction of two metal precursors is challenging due to our limited understanding of precursor ligand effects. Here, the influence of different metal-ligand environments is systematically examined in the synthesis of Pd-Pt nanostructures as a model bimetallic system. Nanodendrites with different spatially defined Pd-Pt compositions are achieved, where the local ligand environments of metal precursors dictate if temporally separated co-reduction dominates to achieve core-shell nanostructures or whether electroless co-deposition proceeds to facilitate alloyed nanostructure formation. As the properties of bimetallic nanomaterials depend on crystal ordering and composition, chemical routes to structurally defined bimetallic nanomaterials are critically needed. The approaches reported here should be applicable to other bimetallic compositions given the established reactivity of coordination complexes available for use as precursors.

Green synthesis and synergistic catalytic effect ofAg/reduced graphene oxide nanocomposite

A nanocomposite of silver nanoparticles and reduced graphene oxide (Ag/rGO) has been developed as a catalyst for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with sodium borohydride, owing to the larger specific surface area and synergistic effect of rGO. A facile and rapid microwave-assisted green route has been used for the uniform deposition of Ag nanoparticles and the reduction of graphene oxide simultaneously with l-arginine as the reducing agent. The resulting Ag/rGO nanocomposite contained about 51 wt% of Ag, and the Ag nanoparticles deposited on the surface of rGO had a mean diameter of 8.6 ± 3.5 nm. Also, the Ag/rGO nanocomposite exhibited excellent catalytic activity and stability toward the reduction of 4-NP to 4-AP with sodium borohydride. The reduction reaction obeyed the pseudo-first-order kinetics. The rate constants increased not only with the increase of temperature and catalyst amount but also with the increase of initial 4-NP concentration, revealing that the support rGO could enhance the catalytic activity via a synergistic effect. A mechanism for the catalytic reduction of 4-NP with NaBH4 by Ag/rGO nanocomposite via both the liquid-phase and solid-phase routes has been suggested.

Mesoporous nano/micro noble metal particles: synthesis and applications

The morphology, size and composition often govern the physical and chemical properties of noble metal units with a size in the nano or micro scale. Thus, the controlled growth of noble metal crystals would help to tailor their unique properties and this would be followed by their practical application. Mesoporous nano/micro noble metal units are types of nanostructured material that have fascinating properties that can generate great potential for various applications. This review presents a general view on the growth mechanisms of porous noble metal units and is focused on recent progresses in their synthetic approaches. Then, their potential applications in the field of drug delivery, cell imaging and SERS substrates, as well as fuel cell catalysts are overviewed.

A universal approach to the preparation of colloidal mesoporous platinum nanoparticles with controlled particle sizes in a wide range from 20 nm to 200 nm

We report a universal method for the preparation of mesoporous Pt nanoparticles with tunable particle sizes by changing the surfactant concentration.

Coordination polymers for catalysis: enhancement of catalytic activity through hierarchical structuring

Hierarchical Prussian white (PW) crystals were synthesized by using a self-aggregation and etching strategy. The crystals exhibit superior catalytic activity in degradation of methylene blue to the non-hierarchical PW crystals.

Mesoporous Pt hollow cubes with controlled shell thicknesses and investigation of their electrocatalytic performance

Mesoporous Pt hollow cubes (MPHCs) are successfully synthesized by using surfactant micelles as the soft-template directing uniformly-sized mesopores.