Pre-carbonization-mediated construction of urchin-like NiFeO superparticles with enhanced CNT growth for efficient oxygen evolution.

In this study, we report the rational design and synthesis of carbonized NiFeO superparticles (CarSPs) hierarchically integrated with densely aligned carbon nanotube (CNT) architectures, hereafter denoted as CarSP-CNTs, which exhibit a biomimetic urchin-like morphology. Through exploitation of the colloidal self-assembly and catalytic functionalities inherent to NiFeO nanoparticles (NPs), we achieve seamless integration of one-dimensional CNT arrays with three-dimensional superstructural frameworks. Systematic investigation reveals that the pre-carbonization of surface-bound organic ligands coupled with subsequent CNT growth induces synergistic interplay between conductive carbon matrices and active spinel oxide phases.

Hydrophobized Metal-Organic Frameworks as Versatile Building Blocks for Tailored Nanocrystal Superlattices.

This study introduces an effective strategy for hydrophobizing metal-organic frameworks (MOFs) using oleyl phosphate (OP) ligands. This modification makes MOF particles dispersible in nonpolar solvents and provides them with colloidal stability akin to traditional colloidal nanocrystals (NCs). The resulting OP-capped MOF particles can then be employed as building blocks for constructing various two-dimensional (2D) and 3D superlattices through self-assembly methods typically used for NCs.

Emergence of Voronoi-Patterned Cellular Membranes via Confinement Transformation of Self-Assembled Metal-Organic Frameworks.

The self-assembly of nanoparticles allows the fabrication of complex, nature-inspired architectures. Among these, Voronoi tessellations─intricate patterns found in many natural systems such as insect wings and plant tissues─have broad implications across materials science, biology, and geography. However, replicating these irregular yet organized features at the nanoscale through nanoparticle self-assembly remains challenging.

Quantifying Interface-Performance Relationships in Electrochemical CO Reduction through Mixed-Dimensional Assembly of Nanocrystal-on-Nanowire Superstructures.

Fine-tuning the interfacial sites within heterogeneous catalysts is pivotal for unravelling the intricate structure-property relationship and optimizing their catalytic performance. Herein, a simple and versatile mixed-dimensional assembly approach is proposed to create nanocrystal-on-nanowire superstructures with precisely adjustable numbers of biphasic interfaces. This method leverages an efficient self-assembly process in which colloidal nanocrystals spontaneously organize onto Ag nanowires, driven by the solvophobic effect.

Densely Branched Carbon Nanotubes for Boosting the Electrochemical Performance of Li-S Batteries.

To address the inherent limitations of conventional carbon nanotubes (CNTs), such as their tendency to agglomerate and scarcity of catalytic sites, the development of branched carbon nanotubes (BCNTs) with a unique hierarchical structure has emerged as a promising solution. Herein, gram scale quantities of densely branched and structurally consistent Ni-Fe decorated branched CNTs (Ni-Fe@BCNT) have been prepared. This uniform and densely branched architecture ensures excellent dispersibility and superior electrical conductivity.

Oriented Linear Self-Assembly of Colloidal Nanocrystals through Regioselective Formation of Hydrogen-Bonded Supramolecular Bridges.

The linear assembly of nanocrystals (NCs) with orientational order presents a significant challenge in the field of colloidal assembly. This study presents an efficient strategy for assembling oleic acid (OAH)-capped, faceted rare earth NCs─such as nanorods, nanoplates, and nanodumbbells─into flexible chain-like superstructures. Remarkably, these NC chains exhibit a high degree of particle orientation even with an interparticle distance reaching up to 15 nm.

Encasing Few-Layer MoS within 2D Ordered Cubic Graphitic Cages to Smooth Trapping-Conversion of Lithium Polysulfides for Dendrite-Free Lithium-Sulfur Batteries.

The industrialization of lithium-sulfur (Li-S) batteries faces challenges due to the shuttling effect of lithium polysulfides (LiPSs) and the growth of lithium dendrites. To address these issues, a simple and scalable method is proposed to synthesize 2D membranes comprising a single layer of cubic graphitic cages encased with few-layer, curved MoS. The distinctive 2D architecture is achieved by confining the epitaxial growth of MoS within the open cages of a 2D-ordered mesoporous graphitic framework (MGF), resulting in MoS@MGF heterostructures with abundant sulfur vacancies.

Shape-Mediated Oriented Assembly of Concave Nanoparticles under Cylindrical Confinement.

This contribution describes the self-assembly of colloidal nanodumbbells (NDs) with tunable shapes within cylindrical channels. We present that the intrinsic concave geometry of NDs endows them with peculiar packing and interlocking behaviors, which, in conjunction with the adjustable confinement constraint, leads to a variety of superstructures such as tilted-ladder chains and crossed-chain superlattices. A mechanistic investigation, corroborated by geometric calculations, reveals that the phase behavior of NDs under strong confinement can be rationalized by the entropy-driven maximization of the packing efficiency.

Amphiphilic Self-Assembly of Nanocrystals at Emulsion Interface Renders Fast and Scalable Quasi-Nanosheet Formation.

Scalable assembly of nanocrystals (NCs) into two-dimensional (2D) nanosheets has aroused great interest, yet it remains under-explored. This is because current 2D assembly methods rely mainly on the use of solid- or liquid-air interfaces, which are inherently difficult for upscaling and thus lack practicability. Here, with a microemulsion-based amphiphilic assembly technique, we achieve a fast and scalable preparation of free-standing nanosheets comprising few-layer, tightly packed NCs, namely, quasi-nanosheets (quasi-NSs).

Native Ligand Carbonization Renders Common Platinum Nanoparticles Highly Durable for Electrocatalytic Oxygen Reduction: Annealing Temperature Matters.

Current protocols for synthesizing monodisperse platinum (Pt) nanoparticles typically involve the use of hydrocarbon molecules as surface-capping ligands. Using Pt nanoparticles as catalysts for the oxygen reduction reaction (ORR), however, these ligands must be removed to expose surface sites. Here, highly durable ORR catalysts are realized without ligand removal; instead, the native ligands are converted into ultrathin, conformal graphitic shells by simple thermal annealing.

A universal, green, and self-reliant electrolytic approach to high-entropy layered (oxy)hydroxide nanosheets for efficient electrocatalytic water oxidation.

The development and exploration of high-entropy materials with tunable chemical compositions and unique structural characteristics, although challenging, have attracted increasingly greater attention over the past few years. Here, we report a universal and green method to prepare high-entropy layered (oxy)hydroxide (HE-LH) nanosheets under ambient conditions. This method is based on a self-reliant electrochemical process, utilizing only low-cost metal foils and electrolytes as reactant, with no need of involving extra alkali salts and/or organic reagents.

2D FeP Nanoframe Superlattices via Space-Confined Topochemical Transformation.

Self-assembled nanocrystal superlattices represent an emergent class of designer materials with potentially programmable functionalities. The ability to construct hierarchically structured nanocrystal superlattices with tailored geometry and porosity is critical for extending their applications. Here, 2D superlattices comprising monolayer FeP nanoframes are synthesized through a space-confined topochemical transformation approach induced by the Kirkendall effect, using carbon-coated Fe O nanocube superlattices as a precursor.

Direct Probing of the Oxygen Evolution Reaction at Single NiFeO Nanocrystal Superparticles with Tunable Structures.

Due to the precisely controllable size, shape, and composition, self-assembled nanocrystal superlattices exhibit unique collective properties and find wide applications in catalysis and energy conversion. Identifying their intrinsic electrocatalytic activity is challenging, as their averaged properties on ensembles can hardly be dissected from binders or additives. We here report the direct measurement of the oxygen evolution reaction at single superparticles self-assembled from ∼8 nm NiFeO and/or ∼4 nm Au nanocrystals using scanning electrochemical cell microscopy.

Self-assembled mesostructured CoFeO nanoparticle superstructures for highly efficient oxygen evolution.

Self-assembly of colloidal nanoparticles (NPs) into well-defined superstructures has been recognized as one of the most promising ways to fabricate rationally-designed functional materials for a variety of applications. Introducing hierarchical mesoporosity into NP superstructures will facilitate mass transport while simultaneously enhancing the accessibility of constituent NPs, which is of critical importance for widening their applications in catalysis and energy-related fields. Herein, we develop a colloidal co-assembly strategy to construct mesostructured, carbon-coated CoFeO NP superstructures (M-C@CFOSs), which show great promise as highly efficient electrocatalysts for the oxygen evolution reaction (OER).

Uniformly coating ZnAl layered double oxide nanosheets with ultra-thin carbon by ligand and phase transformation for enhanced adsorption of anionic pollutants.

The increasing severity of water pollution has strongly urged to develop green and efficient adsorbents for waste-water treatment. In this work, ZnAl layered double oxide nanosheets uniformly coated with ultra-thin amorphous carbon shells (ZnAl-LDO@C) were fabricated by modifying ZnAl layered double hydroxides (LDHs) with molecular ligands followed by calcination. Compared with their counterparts derived from the pristine ZnAl-LDH, ZnAl-LDO@C nanosheets exhibit higher specific surface area with abundant and highly accessible active sites.