Strong Electronic Metal-Support Interactions Enable the Increased Spin State of Co-N Active Sites and Performance for Acidic Oxygen Reduction Reaction.

Nonprecious metal catalysts, particularly -N-C catalysts, are widely recognized as promising contenders for the oxygen reduction reaction (ORR). However, a notable performance gap persists between -N-C catalysts and Pt-based catalysts under acidic conditions. In this study, hybrid catalysts comprising single Co atoms and ultralow concentrations of PtCo intermetallic nanoparticles (NPs) are introduced to enhance ORR performance.

Phosphorus-Doping Enables the Superior Durability of a Palladium Electrocatalyst towards Alkaline Oxygen Reduction Reactions.

The sluggish kinetics of oxygen reduction reactions (ORRs) require considerable Pd in the cathode, hindering the widespread of alkaline fuel cells (AFCs). By alloying Pd with transition metals, the oxygen reduction reaction's catalytic properties can be substantially enhanced. Nevertheless, the utilization of Pd-transition metal alloys in fuel cells is significantly constrained by their inadequate long-term durability due to the propensity of transition metals to leach.

Monomicelle-Directed Engineering of Strained Carbon Nanoribbons as Oxygen Reduction Catalyst.

To date, precisely tailoring local active sites of well-defined earth-abundant metal-free carbon-based electrocatalysts for attractive electrocatalytic oxygen reduction reaction (ORR), remains challenging. Herein, the authors successfully introduce a strain effect on active C-C bonds adjacent to edged graphitic nitrogen (N), which raises appropriate spin-polarization and charge density of carbon active sites and kinetically favor the facilitation of O adsorption and the activation of O-containing intermediates. Thus, the constructed metal-free carbon nanoribbons (CNRs-C) with high-curved edges exhibit outstanding ORR activity with half-wave potentials of 0.

Concave Pt-Zn Nanocubes with High-Index Faceted Pt Skin as Highly Efficient Oxygen Reduction Catalyst.

High dosage of expensive Pt to catalyze the sluggish oxygen reduction reaction (ORR) on the cathode severely impedes the commercialization of proton exchange membrane fuel cells. Therefore, it is urgent to cut down the Pt catalyst by efficiently improving the ORR activity while maintaining high durability. Herein, magic concave Pt-Zn nanocubes with high-index faceted Pt skin (Pt Zn ) are proposed for high-efficiency catalysis toward proton exchange membrane fuel cells.

Evolution of Cu single atom catalysts to nanoclusters during CO reduction to CO.

We synthesized Cu single atoms embedded in a N-doped porous carbon catalyst with a high Faradaic efficiency of 93.5% at -0.50 V (.

Boosting Nitrogen Reduction to Ammonia on FeN Sites by Atomic Spin Regulation.

Understanding the relationship between the electronic state of active sites and N reduction reaction (NRR) performance is essential to explore efficient electrocatalysts. Herein, atomically dispersed Fe and Mo sites are designed and achieved in the form of well-defined FeN and MoN coordination in polyphthalocyanine (PPc) organic framework to investigate the influence of the spin state of FeN on NRR behavior. The neighboring MoN can regulate the spin state of Fe center in FeN from high-spin (d d d ) to medium-spin (d d d ), where the empty d orbitals and separate d electron favor the overlap of Fe 3d with the N 2p orbitals, more effectively activating N≡N triple bond.

Regulating Fe-spin state by atomically dispersed Mn-N in Fe-N-C catalysts with high oxygen reduction activity.

As low-cost electrocatalysts for oxygen reduction reaction applied to fuel cells and metal-air batteries, atomic-dispersed transition metal-nitrogen-carbon materials are emerging, but the genuine mechanism thereof is still arguable. Herein, by rational design and synthesis of dual-metal atomically dispersed Fe,Mn/N-C catalyst as model object, we unravel that the O reduction preferentially takes place on Fe in the FeN /C system with intermediate spin state which possesses one e electron (t4e1) readily penetrating the antibonding π-orbital of oxygen. Both magnetic measurements and theoretical calculation reveal that the adjacent atomically dispersed Mn-N moieties can effectively activate the Fe sites by both spin-state transition and electronic modulation, rendering the excellent ORR performances of Fe,Mn/N-C in both alkaline and acidic media (halfwave positionals are 0.

Interfacial Structure of Water as a New Descriptor of the Hydrogen Evolution Reaction.

Driven by the persisting poor understanding of the sluggish kinetics of the hydrogen evolution reaction (HER) on Pt in alkaline media, a direct correlation of the interfacial water structure and activity is still yet to be established. Herein, using Pt and Pt-Ni nanoparticles we first demonstrate a strong dependence of the proton donor structure on the HER activity and pH. The structure of the first layer changes from the proton acceptors to the donors with increasing pH.

Cu overlayers on tetrahexahedral Pd nanocrystals with high-index facets for CO electroreduction to alcohols.

We investigated CO electroreduction on Cu overlayers on tetrahexahedral Pd nanocrystals with {310} high-index facets, which exhibited a high Faradaic efficiency towards alcohols. The selectivity to ethanol or methanol can be readily tuned by changing the Cu coverage.

Seeds and Potentials Mediated Synthesis of High-Index Faceted Gold Nanocrystals with Enhanced Electrocatalytic Activities.

Because high-index facets (HIFs) possess high surface energy, the metal nanoparticles enclosed with HIFs are eliminated during their growth in a conventional shape-controlled synthesis due to the thermodynamics that drives the particles minimizing their total surface energy. This study develops a double-step potential method to prepare an unprecedentedly stellated Au nanocrystals (NCs) bounded by high-index {711} and {331} facets in deep eutectic solvent (DES) medium. The formation of Au NCs bounded by HIFs was systematically studied.

Platinum-nickel alloy excavated nano-multipods with hexagonal close-packed structure and superior activity towards hydrogen evolution reaction.

Crystal phase regulations may endow materials with enhanced or new functionalities. However, syntheses of noble metal-based allomorphic nanomaterials are extremely difficult, and only a few successful examples have been found. Herein, we report the discovery of hexagonal close-packed Pt-Ni alloy, despite the fact that Pt-Ni alloys are typically crystallized in face-centred cubic structures.

Hydrogen adsorption-mediated synthesis of concave Pt nanocubes and their enhanced electrocatalytic activity.

Concave nanocubes are enclosed by high-index facets and have negative curvature; they are expected to have enhanced reactivity, as compared to nanocubes with flat surfaces. Herein, we propose and demonstrate a new strategy for the synthesis of concave Pt nanocubes with {hk0} high-index facets, by using a hydrogen adsorption-mediated electrochemical square-wave potential method. It was found that Pt atoms prefer to deposit on edge sites rather than terrace sites on Pt surfaces with intensive hydrogen adsorption, resulting in the formation of concave structures.

A comparative study of CO adsorption on tetrahexahedral Pt nanocrystals and interrelated Pt single crystal electrodes by using cyclic voltammetry and in situ FTIR spectroscopy.

This study focuses on CO adsorption at tetrahexahedral Pt nanocrystals (THH Pt NCs) by using cyclic voltammetry and in situ FTIR spectroscopy. Since the electrochemically prepared THH Pt NCs in this study are enclosed by {730} facets which could be considered by a subfacet configuration of 2{210} + {310}, we have also studied CO adsorption on the interrelated Pt(310) and Pt(210) single crystal electrodes as a comparison. Cyclic voltammetry results demonstrated that CO adsorbs dominantly on the (100) sites of THH Pt NCs at low CO coverage (θ(CO)≤ 0.