Direct synthesis of bimetallic PtCo mesoporous nanospheres as efficient bifunctional electrocatalysts for both oxygen reduction reaction and methanol oxidation reaction

Precise structural regulation of copper-based electrocatalysts for sustainable nitrate reduction to ammonia

The electrocatalytic reduction of nitrate to ammonia (NRA) technology not only achieves the effective removal of nitrates in the environment but also produces value-added products-NH3. In recent years, copper-based materials have shown tremendous application prospects in this field due to their excellent conductivity, moderate cost, and their proximity of d orbital energy levels to the LUMO π∗ molecular orbitals of nitrate. This review starts with copper-based catalysts to elucidate the reaction mechanisms of NRA and its influencing factors, while summarizing and analyzing the principles and pros and cons of various modification strategies. Then, we will explore the impact of different modification strategies on improving NRA performance and the underlying theoretical mechanisms. Finally, this review proposes the current challenges and prospects of copper-based materials, aiming to provide a reference for the further development and industrial application of copper-based catalysts.

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.

Modulating the intrinsic properties of platinum–cobalt nanowires for enhanced electrocatalysis of the oxygen reduction reaction

The ability to improve the intrinsic activity of nanoalloy electrocatalysts is essential for designing highly efficient electrocatalysts by optimizing the basic physical properties of the nanoalloy.

Solvent assistance induced surface N-modification of PtCu aerogels and their enhanced electrocatalytic properties

A facile method involving the nitrogen modification of PtCu aerogel surfaces with N-methyl pyrrolidone as the sole nitrogen source is reported. The half wave potential (E1/2) of the PtCu aerogels was 0.932 V and the electrochemical active surface area (ECSA) was 102.04 m2 g-1 for the oxygen reduction reaction (ORR), and the mass activity (MA) for the methanol electrooxidation reaction (MOR) was measured to be 4.08 A mg-1, values better than those of a commercial Pt/C catalyst and other reported Pt-based catalysts.

Porous Noble Metal Electrocatalysts: Synthesis, Performance, and Development

Active sites (intrinsic activity, quantity, and distribution), electron transfer, and mass diffusion are three important factors affecting the performance of electrocatalysts. Composed of highly active components which are built into various network structures, porous noble metal is an inherently promising electrocatalysts. In recent years, great efforts have been made to explore new efficient synthesis methods and establish structural-performance relationships in the field of porous noble metal electrocatalysis. In this review, the very recent progress in strategies for preparing porous noble metal, including innovation and deeper understanding of traditional methods is summarized. A discussion of relationship between porous noble metal structure and electrocatalytic performance, such as accessibility of active sites, connectivity of skeleton structures, channels dimensions, and hierarchical structures, is provided.

Ternary PtFeCo alloys on graphene with high electrocatalytic activities for methanol oxidation

Ternary PtFeCo alloys as alternatives to conventional Pt electrocatalysts are highly important in the field of the methanol oxidation reaction. In this study, we demonstrate a one-pot two-step reduction method for the synthesis of graphene supported PtFeCo alloy nanocomposites as an integrated binder-free catalyst. The synergistic effect of alloying with Fe and Co as well as graphene decorating contributes to an increase in the utilization of the noble metal, namely, reducing the amount of Pt in the nanocomposites to 7%. After tailoring the elemental composition of the alloys, Pt₅₂Fe₂₉Co₁₉@G-7% exhibits a mass activity/specific activity of 1758.2 mA mg^-1_Pt/3.42 mA cm^-2 that is 3.13/3.45 times that of commercial Pt/C in an acidic medium. Impressively, it showed a superior mass current density of 9356.1 mA mg^-1_Pt at 60 °C which is close to the operating temperature of direct methanol fuel cells. Moreover, the as-obtained Pt₅₂Fe₂₉Co₁₉@G-7% also exhibited excellent CO tolerance and reliable stability compared to commercial Pt/C. The structural characterization further verifies that the surface strain and electronic effect play a critical role in determining the electrocatalytic properties of PtFeCo@G nanocomposites for the methanol oxidation reaction.

Self-assembly of block copolymers towards mesoporous materials for energy storage and conversion systems

This paper reviews the progress in the field of block copolymer-templated mesoporous materials, including synthetic methods, morphological and pore size control and their potential applications in energy storage and conversion devices.

Nonsiliceous Mesoporous Materials: Design and Applications in Energy Conversion and Storage

In this work, the progress in the design of nonsiliceous mesoporous materials (nonSiMPMs) over the last five years from the perspectives of the chemical composition, morphology, loading, and surface modification is summarized. Carbon, metal, and metal oxide are in focus, which are the most promising compositions. Then, representative applications of nonSiMPMs are demonstrated in energy conversion and storage, including recent technical advances in dye-sensitized solar cells, perovskite solar cells, photocatalysts, electrocatalysts, fuel cells, storage batteries, supercapacitors, and hydrogen storage systems. Finally, the requirements and challenges of the design and application of nonSiMPMs are outlined.

PtPdRh Mesoporous Nanospheres: An Efficient Catalyst for Methanol Electro-Oxidation

Porous multimetallic alloyed nanostructures possess unique physical and chemical properties to generate promising potential in fuel cells. However, the controllable synthesis of this kind of materials still remains challenging. Herein, we report a facile method for the one-pot, high-yield synthesis of trimetallic PtPdRh mesoporous nanospheres (PtPdRh MNs) under mild conditions. The resultant PtPdRh MNs possess the features of uniform shape, a narrow size distribution, plenty of well-defined mesopores, highly open structure, and multicomponent effects, which impart advantages such as large surface area, favorable mass diffusion, high utilization of electrocatalysts, and synergy among the various metal components. Benefitting from the synergetic effects originating from the multimetallic composition and unique mesoporous structure, the as-prepared PtPdRh MNs exhibit remarkably enhanced electrocatalytic performance for methanol oxidation reaction relative to bimetallic PtPd MNs and commercial Pt/C catalyst.

One-step fabrication of bimetallic PtNi mesoporous nanospheres as an efficient catalyst for the oxygen reduction reaction

The controlled synthesis of Pt-based bimetallic porous nanostructures is highly important for the design of electrocatalysts with high performance. Herein, we report a one-step method for the direct synthesis of well-dispersed bimetallic PtNi mesoporous nanospheres (PtNi MNs) at high yield. Benefitting from the synergistic effect of composition (bimetallic PtNi) and structure (mesoporous and highly open structure), the as-obtained PtNi MNs exhibit superior catalytic activity and stability for the oxygen reduction reaction.