Mesoporous High-Entropy Alloy Films.

High-entropy alloys (HEAs) are promising materials for electrochemical energy applications due to their excellent catalytic performance and durability. However, the controlled synthesis of HEAs with a well-defined structure and a uniform composition distribution remains a challenge. Herein, a soft template-assisted electrodeposition technique is used to fabricate a mesoporous HEA (m-HEA) film with a uniform composition distribution of Pt, Pd, Rh, Ru, and Cu, providing a suitable platform for investigating structure-performance relationships.

Tailored Design of Mesoporous Nanospheres with High Entropic Alloy Sites for Efficient Redox Electrocatalysis.

High Entropy Alloys (HEAs) are a versatile material with unique properties, tailored for various applications. They enable pH-sensitive electrocatalytic transformations like hydrogen evolution reaction (HER) and hydrogen oxidation reactions (HOR) in alkaline media. Mesoporous nanostructures with high surface area are preferred for these electrochemical reactions, but designing mesoporous HEA sis challenging.

High entropy alloying strategy for accomplishing quintuple-nanoparticles grafted carbon towards exceptional high-performance overall seawater splitting.

High entropy alloys (HEAs), a novel class of material, have been explored in terms of their excellent mechanical properties. Seawater electrolysis is a step towards sustainable production of carbon-neutral fuels such as H, O, and industrially demanding Cl. Herein, we report a practically viable FeCoNiMnCr HEA nanoparticles system grafted on a conductive carbon matrix for promising seawater electrolysis.

FeCoNiMnCr High-Entropy Alloy Nanoparticle-Grafted NCNTs with Promising Performance in the Ohmic Polarization Region of Fuel Cells.

We report a user-friendly methodology for the successful designing of targeted single-phased face-centered cubic (fcc) FeCoNiMnCr high-entropy alloy (HEA) nanoparticle-grafted N-doped carbon nanotubes (CNTs). The nanostructure assimilates the advantages of N-doped carbon and HEA nanoparticles as a core for the efficient promotion of electrochemical oxygen reduction reaction (ORR). It emulates the commercial Pt-C electrocatalyst for ORR and shows promise for better performance in the Ohmic polarization region of fuel cells.

Atomic Arrangement Modulation in CoFe Nanoparticles Encapsulated in N-Doped Carbon Nanostructures for Efficient Oxygen Reduction Reaction.

The properties and, hence, the application of materials are dependent on the way their constituent atoms are arranged. Here, we report a facile approach to produce body-centered cubic (bcc) and face-centered cubic (fcc) phases of bimetallic FeCo crystalline nanoparticles embedded into nitrogen-doped carbon nanotubes (NCNTs) with equal loading and almost similar particle size for both crystalline phases by a rational selection of precursors. The two electrocatalysts with similar composition but different crystalline structures of the encapsulated nanoparticles have allowed us, for the first time, to account for the effect of crystal structure on the overall work function of electrocatalysts and the concomitant correlation with the oxygen reduction reaction (ORR).

Unique One-Step Strategy for Nonmetallic and Metallic Heteroatom Doped Carbonaceous Materials.

Nonmetallic and metallic heteroatom doped carbonaceous materials have garnered tremendous research attention due to a potential replacement to the precious Pt-group and (Ru, Ir)-oxide based catalysts and are essential part of the next-generation electrode catalysts for fuel cells, electrolyzers, and metal-air batteries. In this regard, we focus on three important categories of carbonaceous material, namely, metal-free heteroatom doped, transition metal heteroatom codoped, and carbon nitride (CN) based hybrid materials. Implications of various strategies, using one-step pyrolysis technique have been discussed for the effective design of heteroatom modified carbonaceous electrocatalysts.

High-entropy alloys for water oxidation: a new class of electrocatalysts to look out for.

High-entropy alloys (HEAs) with five or more elements can provide near-continuous adsorption energies and can be optimized for superior persistent catalytic activity. This report presents electrochemical water oxidation facilitated by employing graphene and FeCoNiCuCr HEA nanoparticle based composites prepared via the mechanical milling of graphite-metal powders. The composite efficiently facilitates water oxidation with a low overpotential of 330 mV at 10 mA cm-2, and high specific and mass activities (∼143 mA cm-2 and 380 mA mg-1, respectively, at 1.

Energy-Efficient Rational Designing of Multifunctional Nanocomposites by Preferential Anchoring of Metal Ions via Fermi Level Positioning of Carbon Nanostructures.

Despite the availability and dedicated studies on a variety of carbon nanostructures, amorphous carbon is still a preferred support for a wide range of commercially available metal catalysts. In order to shed some light on this, we carried out electroless deposition of metal nanoparticles on various carbon nanostructures such as amorphous carbon (a-C), carbon nanotubes (CNTs), and nitrogen-doped CNTs (NCNTs) under similar experimental conditions. The main objective is to elucidate the preferable deposition on a particular carbon nanostructure, if any, and understand the underlying mechanism.

Inner Sphere Electron Transfer Promotion on Homogeneously Dispersed Fe-N Centers for Energy-Efficient Oxygen Reduction Reaction.

The study reports the optimized incorporation of pyridinic nitrogen in nitrogen-doped carbon nanotubes (CNTs) to realize effective Fe-N centers throughout the framework. The study unveils nitrogen as a valuable asset to promote the homogeneous dispersion of Fe moieties throughout the CNT framework, which is a necessary component to institute uniform Fe-N centers. In addition, pyridinic nitrogen causes disruption in strongly delocalized π-electrons, which impart electron-withdrawing nature in the carbon matrix, resulting in an anodic shift in oxygen reduction reaction (ORR) onset potential ().

Mechanistic Investigation into Efficient Water Oxidation by Co-Ni-Based Hybrid Oxide-Hydroxide Flowers.

Oxides are envisioned as promising catalysts to facilitate water oxidation, and the benign presence of hydroxide moieties can further enhance the catalyst performance. However, the nature of synergy between oxides and hydroxides remains elusive. In this study, we have designed a one-pot solution growth technique for the synthesis of flower-shaped N-doped-C-enveloped NiCoO/NiCo(OH) catalysts with varying oxide and hydroxide contents and investigated their water oxidation behavior.