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.

Metal-Based Electrocatalysts for Methanol Electro-Oxidation: Progress, Opportunities, and Challenges

Direct methanol fuel cells (DMFCs) are among the most promising portable power supplies because of their unique advantages, including high energy density/mobility of liquid fuels, low working temperature, and low emission of pollutants. Various metal-based anode catalysts have been extensively studied and utilized for the essential methanol oxidation reaction (MOR) due to their superior electrocatalytic performance. At present, especially with the rapid advance of nanotechnology, enormous efforts have been exerted to further enhance the catalytic performance and minimize the use of precious metals. Constructing multicomponent metal-based nanocatalysts with precisely designed structures can achieve this goal by providing highly tunable compositional and structural characteristics, which is promising for the modification and optimization of their related electrochemical properties. The recent advances of metal-based electrocatalytic materials with rationally designed nanostructures and chemistries for MOR in DMFCs are highlighted and summarized herein. The effects of the well-defined nanoarchitectures on the improved electrochemical properties of the catalysts are illustrated. Finally, conclusive perspectives are provided on the opportunities and challenges for further refining the nanostructure of metal-based catalysts and improving electrocatalytic performance, as well as the commercial viability.

Bimetallic RuPd nanoparticles in ionic liquids: selective catalysts for the hydrogenation of aromatic compounds

Bimetallic RuPd nanoparticles are effective catalysts for the hydrogenation of aromatic compounds and the activity and selectivity depend on the Ru : Pd ratio.

High-efficiency methanol oxidation electrocatalysts realized by ultrathin PtRuM-O (M = Ni, Fe, Co) nanosheets

A general method for controlling the synthesis of a class of ultrathin PtRuM-O (M = Ni, Fe, Co) NSs is reported for the first time. By optimizing the metal ratio, the Pt₇RuNi₂-O NS catalyst is found to have the highest electrocatalytic activity (mass activity, 3.57 A mg_Pt^-1) for the MOR among PtRuM-O NSs and PtRu-O NSs, which is 10.5 times higher than that of commercial Pt/C (0.34 A mg_Pt^-1). And the Pt₇RuNi₂-O NSs also have better stability and CO anti-poisoning properties in the prepared materials. In addition, the ultrathin Pt₇RuNi₂-O NS catalyst also shows the highest performance among reported Pt-based catalysts for the MOR in acidic medium.

Monodisperse thiourea functionalized graphene oxide-based PtRu nanocatalysts for alcohol oxidation

Addressed herein, thiourea functionalized graphene oxide-based PtRu nanocatalysts (PtRu@T/GO) has been synthesized and characterized by several techniques and performed for methanol oxidation reactions as novel catalysts. In this study, graphene oxide (GO) was functionalized with thiourea (T/GO) in order to obtain monothiol functionalized graphene and increase the stability and activity of the nanocatalysts. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), TEM (transmission electron microscopy) and high-resolution transmission electron microscopy (HR-TEM) were used for characterization of the prepared nanocatalysts. The results obtained from these techniques showed that the prepared nanocatalysts were in a highly crystalline form, well dispersed on T/GO, very small in size and colloidally stable. The average size of the synthesized nanocatalysts determined by TEM analysis was found to be 3.86 ± 0.59 nm. With HR-TEM analysis, the atomic lattice fringes of the nanocatalysts were calculated to be 0.23 nm. After the full characterization of the prepared nanocatalysts, they were tried for the methanol oxidation reaction (MOR) and it was observed that 97.3% of the initial performance was maintained even after 1000 cycles while exhibiting great catalytic activity and stability with the help of T/GO. Thus, the arranged nanocatalysts displayed great heterogeneous catalyst characteristics for the methanol oxidation response.

Facile Synthesis Of Composition-Controllable PtPdAuTe Nanowires As Superior Electrocatalysts For Direct Methanol Fuel Cells

Multicomponent Pt-based nanowires (NWs) have attracted widespread attention as eletrocatalysts toward direct alcohol fuel cells because of their unique one-dimensional structure and high reaction dynamics. Quaternary PtPdAuTe NWs are designed via a facile template method, and NWs with a different composition are obtained by adjusting the feed ratio of metal precursors. The direct displacement reaction of metal precursors with Te NWs and the partial oxidation of Te lead to the formation of quaternary NWs. The rough surface and abundant reactive sites deriving from the rearrangement of metal atoms on the Te NWs surface endow the PtPdAuTe NWs with a superior electrocatalytic property and durability for methanol oxidation. The Pt₂₀ Pd₂₀ Au₁₀ Te₅₀ NWs display the largest mass activity and best stability among all catalysts. The preparation of PtPdAuTe NWs could provide a viable strategy for the preparation of other multicomponent NWs.

Construction of a hollow porous carbon spheres@CoP/nitrogen-doped carbon supported platinum catalyst for high performance methanol oxidation

A Pt–HPCS@CoP/NC catalyst with excellent catalytic activity, CO-tolerance and durability was synthesized for the methanol oxidation reaction.

Effect of thiophene S on the enhanced ORR electrocatalytic performance of sulfur-doped graphene quantum dot/reduced graphene oxide nanocomposites

In this study, a novel and simple hydrothermal method was developed to synthesize sulfur-doped graphene quantum dots (S-GQDs) with a diameter of 1-6 nm and S-GQD/reduced graphene oxide hybrids. The results indicated that an increase in the sulfur content led to superior ORR electrocatalytic activity. Moreover, it is found that thiophene S plays a significant role in the electrocatalytic activity. In addition, the average electron transfer number depends on the content of thiophene S. It is believed that the proposed synthesis strategy is a general and effective method for designing high-performance metal-free electrocatalytic materials.

One-pot synthesis of bimetallic PdCu nanoframes as an efficient catalyst for the methanol oxidation reaction

A one-pot method is developed for the synthesis of PdCu nanoframes which are an active catalyst for the methanol oxidation reaction.

Branched Pd@Rh core@shell nanocrystals with exposed Rh {100} facets: an effective electrocatalyst for hydrazine electro-oxidation

Shape control of noble metal (NM) nanocrystals (NCs) is of great importance for improving their electrocatalytic performance. In this report, branched Pd@Rh core@shell NCs that have right square prism-like arms with preferential exposure of Rh {100} facets (denoted as b-Pd@Rh-NCs thereafter) are synthesized and utilized as an electrocatalyst for the hydrazine electrooxidation (HEO) in acidic and alkaline electrolytes. The b-Pd@Rh-NCs are obtained by the heteroepitaxial growth of Rh on the pre-formed branched Pd NCs (denoted as b-Pd-NCs thereafter) core in the presence of poly(vinyl pyrrolidone) (PVP) and bromide ions. A comparative analysis of the voltammetric data for the HEO shows a higher activity on the b-Pd@Rh-NCs exposed with Rh {100} faces than on Rh black, the b-Pd-NCs, and Pd black in acid and alkaline solutions, indicating a structure sensitivity of the reaction. Analysis of the products from the b-Pd@Rh-NCs catalysed HEO reveals a very high hydrazine fuel efficiency, as determined by on-line differential electrochemical mass spectrometry (DEMS).