A Strategy for the High Dispersion of PtRu Nanoparticles onto Carbon Nanotubes and Their Electrocatalytic Oxidation of Methanol

Low-temperature N-anchored ordered Pt3Co intermetallic nanoparticles as electrocatalysts for methanol oxidation reaction

To enhance nanocatalyst performance and durability for the methanol oxidation reaction (MOR) in a direct methanol fuel cell, small-sized (2.1 nm) and structurally ordered Pt₃Co intermetallic nanoparticles are uniformly anchored onto nitrogen-doped carbon nanotubes (N-CNTs) via a low-temperature N-anchoring method, and the N-doping abilities of different N-containing reagents are compared. After investigating the microstructure of Pt₃Co/N-CNTs and evaluating their catalytic activity for the MOR, the results show that N-doping facilitates the uniform loading of Pt₃Co NPs and plays a crucial role in improving the electrocatalytic activity of Pt₃Co NPs supported on CNTs. Pt₃Co/N-CNT-M with melamine as the N dopant exhibits the highest MOR activity and stability among all N-CNT-supported Pt₃Co NPs and Pt/N-CNT-M. Density functional theory calculations suggest that the doping of N enhances the binding energy of CNTs to Pt₃Co NPs, and the MOR mechanism shows that the introduction of Co is the reason for the enhancement of MOR reaction kinetics. The excellent electrochemical performance of Pt₃Co/N-CNT-M is mainly attributed to the synergistic effect of N and Pt₃Co intermetallic nanoparticles. The combination of ordered alloy nanoparticles and high-performance carrier N-CNT-M described herein exhibits great potential for fuel cells and may provide an unequivocal direction for the optimization of catalyst performance.

A general route to coat poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) on various substrates and the derived N, P, S-doped hollow carbon shells for catalysis

The construction of core-shell structures through surface coating, and then making use of the synergistic effects between the core and shell to design and synthesize heterogeneous catalysts is a hot topic in the heterogeneous catalysis field. Developing a general coating route with functional shell materials is further highly desirable. Here we found that a poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) (PZS) layer can be generally coated on various substrates with different components and morphologies, including metal oxides, noble metal nanoparticles, carbon materials and metal-organic frameworks (MOFs). In addition, the coating thickness could be well controlled through simply adjusting the amount of monomers. Taking advantage of the heteroatoms in the PZS layer and the synergistic effect between the core and shell, new methods for fabrication of co-doped hollow carbon shell catalysts and transition metal phosphide nanoparticles were developed. As a proof-of-concept application, the N, P, S-doped hollow carbon shells prepared by calcination of a ZnCo-ZIFs@PZS core-shell structure could act as a good carbo-catalyst for selective oxidation of C-H bonds in water.

Graphitic-C3N4 quantum dots modified carbon nanotubes as a novel support material for a low Pt loading fuel cell catalyst

A novel graphitic-C₃N₄ quantum dot modified carbon nanotube composite supported PtRu catalyst is prepared by π–π stacking. The enhanced catalytic performance of the catalyst is due to the better dispersion of PtRu NPs and the strong metal–support interaction (SMSI).

Uniformly deposited Pt nanoparticles onto crosslinked ionic liquids wrapped carbon nanotubes for methanol electrooxidation

A type of skin-core structured hybrid with a multi-walled carbon nanotube (MWCNT) center was synthesized by in situ free-radical polymerization of vinyl-benzyl ionic liquid and divinylbenzene on the outer surface of MWCNTs.

Lamellar Ni/Al-SBA-15 fibers: preparation, characterization, and applications as highly efficient catalysts for amine and imine syntheses

A novel lamellar Ni/Al-SBA-15 fiber catalyst was prepared and successfully utilized in one-pot syntheses of amines and imines.

Influence of noncovalent modification on dispersion state of multiwalled carbon nanotubes in melt-mixed immiscible polymer blends

Multiwalled carbon nanotubes (MWNTs) were melt-mixed with polyamide6 (PA6) and acrylonitrile butadiene styrene copolymer (ABS) to obtain electrically conducting composites. MWNTs were noncovalently modified with sodium salt of 6-aminocaproic acid (MWNTs-m1) and 3-pyrenealdehyde (MWNTs-m2) to 'deagglomerate' MWNTs. Raman spectroscopic analysis indicated a G-band shift from ∼1581.9 cm(-1) for pristine MWNTs to ∼1590.2 cm(-1) for MWNTs-m1 and ∼1588.8 cm(-1) for MWNTs-m2, indicating the interaction between MWNTs and the respective modifier molecules. Blends showed 'co-continuous' morphology on the addition of MWNTs. TEM observations showed that a higher population of pristine MWNTs exhibited a 'nanoagglomerated' state in PA6 and ABS phases in the case of a 40/60 PA6/ABS blend, unlike a 60/40 blend, which depicted a higher population of 'individualized' MWNTs. Further, the corresponding blends with MWNTs-m1 and MWNTs-m2 showed 'nanoagglomerated' and 'individualized' MWNTs. Blends with pristine MWNTs showed an increase in DC electrical conductivity with an increase in PA6 concentration in the blend. Moreover, the corresponding blends with MWNTs-m1 and MWNTs-m2 exhibited an increased DC electrical conductivity value as compared to the corresponding blend with pristine MWNTs. Ratio of the intensity (H1/H2) of the crystallization peak at lower temperature (H1) to the intensity of the crystallization peak at higher temperature (H2) depicted lower values for blends with pristine MWNTs as compared to the corresponding blends with MWNTs-m1 and MWNTs-m2. TGA studies indicated the formation of a thicker 'interphase' involving MWNTs and the interacting polymer chains.

The effect of hydrothermal treatment time and level of carbon coating on the performance of PtRu/C catalysts in a direct methanol fuel cell

The existence of carbon nanolayer on the surface of the PtRu/C catalyst from glucosein situcarbonization inhibits the migration and coalescence of PtRu metal nanoparticles on the support.

Pt-based nanoparticles on non-covalent functionalized carbon nanotubes as effective electrocatalysts for proton exchange membrane fuel cells

This review presents the latest progress in the development of non-covalent functionalized CNT supported Pt-based electrocatalysts for fuel cells.