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We present a novel approach to adjust the symmetry of Au octahedral nanocrystals in two-dimensional superlattices. By modifying the content of free polymeric ligands added in the nanocrystal solution, we achieve Au nanocrystal superlattices with tip-on-tip arrangements that significantly enhance the surface-enhanced Raman spectroscopy performance. [ABSTRACT FROM AUTHOR]

Silicon, serving as an anode material of Li‐ion batteries, offers a theoretical capacity significantly higher than graphite, but its practical application is hindered by poor conductivity, low lithium ion diffusivity, and severe volumetric expansion. Here, a simple and eco‐friendly methodology is proposed to synthesize precisely prelithiated polyacrylic acid binder, optimizing the interface between the binder and micron Si particles. The incorporation of these binders not only mitigates the detrimental effects of volumetric expansion but also enhances mechanical strength, and ionic conductivity of the anode, significantly improving the initial Coulombic efficiency (ICE), cycling stability, and rate performance of micron‐sized Si anodes. This study not only highlights the potential of prelithiated binders in overcoming the limitations of micron‐sized Si anodes but also sets a new benchmark for the development of high‐capacity, eco‐friendly Li‐ion batteries. [ABSTRACT FROM AUTHOR]

The inclusion of colloidal particles into 3D porous constructs to realize heterostructure ensembles enhances surface interactions and energy transfer that can transform the catalytic properties of conventional catalysts. However, assembling hydrophobic colloidal nanoparticles within hydrophilic 3D porous matrices to create tailored heterostructures and catalytic properties is particularly challenging. Here, a modified ligand grafting method is presented to spontaneously assemble CdS inorganic colloidal quantum dots within a metal‐organic framework (MOF) derived porous framework for efficient photocatalytic CO2 reduction. The grafted long chain molecular ligands effectively suppress phase separation and endow a molecular‐recognition effect to form ordered assembly microstructures. The proof‐of‐concept assembly of CdS and Prussian blue analogues (PBA) derived Co3O4 facilitates a high density of heterojunctions formation, improving charge transfer and extended lifetimes of photo‐induced electrons. Consequently, CdS/Co3O4 assembly exhibits exceptionally active and stable photocatalytic CO2 reduction activity, with a CO production rate of 73.9 µmol g−1 h−1 and CO selectivity of 98.9%. Importantly, the ligand grafting method can be generalized to achieve spontaneous assembly of quantum dots within various metal organic framework derived porous scaffolds. This work provides a rational strategy for precise self‐assembly of colloidal nanoparticles within porous microstructures, allowing tailored heterointerfaces for functional materials and applications. [ABSTRACT FROM AUTHOR]

A persistent challenge in utilizing Au nanocrystals for surface‐enhanced Raman spectroscopy (SERS) lies in achieving controllable superstructures that maximize SERS performance. Here, a novel strategy is proposed to enhance the SERS performance by precisely adjusting the tip arrangements of Au nanobipyramids (BPs) in two‐dimensional (2D) superlattices (SLs). This is achieved through ligand‐exchange of Au BPs, followed by liquid‐air interfacial assembly, resulting in large‐area, transferrable SL membranes. The key to controlling the arrangement of Au BPs in the SLs is the regulation of the amount of free ligands added during self‐assembly, which allows for the precise formation of various configurations such as tilted SLs, tip‐on‐tip SLs, and tip‐to‐tip SLs. Among these configurations, tip‐on‐tip SLs exhibit the highest enhancement factor for SERS, reaching an impressive value of 1.95×108, with uniform and consistent SERS signals across a large area. The experimental findings are further corroborated by simulations using the finite element method. This study establishes an efficient method for engineering the microstructure of 2D SLs composed of Au BPs, highlighting the importance of fine‐tuning the tip arrangements of Au BPs to regulate SERS performance. [ABSTRACT FROM AUTHOR]

We present a novel method for synthesizing monodisperse, star-shaped FeCoMnOx nanocrystals with tunable concavity. Through liquid–air interfacial assembly, these colloidal nanostars can form two-dimensional superlattices, which are characterized by low packing densities. Notably, the ability to adjust the degree of concavity of nanostars allows for the tuning of the packing symmetry of the assembled superlattices. [ABSTRACT FROM AUTHOR]

Incorporating conductive and porous components as pillaring materials into the interlayers of two‐dimensional (2D) materials offers a solution to the restacking issue and enables the creation of multifunctional hetero‐superstructures. Here, multilayer MXene superlattices intercalated with monolayer mesoporous carbon frameworks (MMCFs) are synthesized by colloidal co‐assembly of MXene Ti3C2Tx nanosheets and Fe3O4 nanoparticles. The intercalated MMCFs not only increase interlayer spacing and create porous channels for fast mass transport but also act as conductive pillars to facilitate electron transfer along the z‐direction. These unique structural features allow for the full utilization of unilamellar MXene, making the resulting Ti3C2Tx/MMCF superlattices particularly suitable for capacitive energy storage in organic electrolytes containing bulky ions. As a demonstration, supercapacitors made from Ti3C2Tx/MMCFs exhibit a volumetric capacitance of 317 F cm−3 in a tetraethylammonium tetrafluoroborate/propylene carbonate electrolyte. Furthermore, on‐chip micro‐supercapacitors (MSCs) fabricated from Ti3C2Tx/MMCFs, using the ionic liquid 1‐ethyl‐3‐methylimidazolium tetrafluoroborate as an electrolyte, achieve an areal energy density of 0.10 mWh cm−2, surpassing that of most state‐of‐the‐art MXene‐based MSCs developed to date. This study not only highlights the significant potential of Ti3C2Tx/MMCFs for efficient capacitive energy storage in organic electrolytes but also introduces a new method for synthesizing 2D porous hetero‐superstructures for various applications. [ABSTRACT FROM AUTHOR]

The lifespan of proton‐exchange membrane fuel cells heavily relies on the durability of the carbon support of cathode catalysts. However, commercial carbon supports like ketjenblack (KB) and Vulcan carbon (VC) face the challenge of balancing porosity, surface area, and electrochemical stability. To address this issue, a 3D porous wrinkled graphitic carbon (PWGC) is designed and synthesized using a catalyst‐free, plasma‐enhanced chemical vapor deposition approach. The resulting PWGC possesses a hierarchically porous structure with a high surface area, a high degree of graphitization, and exceptional corrosion resistance. As a result, the Pt/PWGC catalysts with the use of PWGC as the carbon support demonstrate superior high potential stability compared to those made with KB and VC as the carbon support. Additionally, a sacrificial layer strategy is introduced to further reduce PWGC corrosion, resulting in Pt@C/PWGC catalysts that show significantly improved durability in membrane electrode assembly tests. After 5K voltage cycles from 1.0 to 1.5 V, the retention of electrochemically active surface area approaches 56.8%, surpassing the 23.6% retention of commercial Pt/C catalysts tested under the same conditions. [ABSTRACT FROM AUTHOR]

The exceptional properties of 2D transition metal carbides and nitrides (MXene) have led to numerous promising applications. However, the performance of MXene is often dependent on the size of the flakes, and obtaining large‐sized, high‐quality MXene flakes remains challenging. Herein, a carbon nanotube (CNT)‐assisted exfoliation strategy is introduced, which significantly improves the yield of large‐flake MXene while entirely transforming the centrifugation residues into small‐flake MXene, resulting in waste‐free synthesis of MXene. The average size of the obtained MXene flakes can reach over 10 and 0.7 µm for the two populations, respectively. Additionally, the capacitive performance of MXene can be greatly enhanced with a small amount of CNTs. As a proof of concept, a planar interdigital micro‐supercapacitor with heterogeneous layers assembled by large‐ and small‐flake MXene simultaneously exhibits outstanding synergistic enhancement in volumetric capacitance (1072 F cm⁻3) and energy density (53.5 mWh cm⁻3). This CNT‐assisted method provides explicit directions for achieving the ideal utilization of MXene, improving the yield of large flakes while making judicious use of waste, to meet specific application needs. [ABSTRACT FROM AUTHOR]

Members of transition metal dichalcogenides, particularly molybdenum disulfide, have been recognized as promising efficient and durable earth‐abundant catalysts for the hydrogen evolution reaction (HER). Despite the recent significant progress, the HER performance of MoS2 is still far from satisfactory, especially at high current densities. Here, a simultaneous multilevel structural control strategy is reported to cooperatively boost hydrogen evolution on 2H‐MoS2, unlocking its potential for practical hydrogen evolution at ampere‐level current densities. By confining the epitaxial growth of few‐layered, curved MoS2 nanosheets within a tubular mesoporous graphitic framework, one can achieve deliberate structural control of MoS2 across seven orders of magnitude on the length scale. The resulting MoS2@C supertubes, benefiting from their unique structural features across atomic‐to‐microscopic scales, are characterized by abundant edge sites and sulfur vacancies, facilitated charge and mass transport, and rapid gas bubble removal. As a consequence, such MoS2@C supertubes exhibit exceptional high‐current‐density HER activity surpassing previously reported 2H‐MoS2 catalysts and even commercial Pt/C catalysts. This work demonstrates the validity of multilevel structural engineering of 2H‐MoS2 by confinement growth, opening a viable route of developing low‐cost catalysts toward practical hydrogen evolution. [ABSTRACT FROM AUTHOR]

Designing highly‐efficient, cost‐effective, and stable electrocatalysts for water splitting is of great significance for implementing renewable energy technologies. Herein, a self‐templated strategy is employed to fabricate 2D porous electrocatalysts of heterometallic phosphides featuring a cage‐in‐cage superlattice architecture. The as‐made heterometallic phosphide electrocatalysts, comprising a layer of close‐packed CoFeP nanocages intimately embedded in an interconnected carbon‐cage framework, are converted from carbon‐coated CoFeO nanocrystal superlattices by one‐step phosphidation. Benefiting from the unique hierarchical porous structure and the ability of modulating the Co/Fe molar ratio, such 2D CoFeP @ C cage‐in‐cage superlattices show remarkable activity and stability for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. Moreover, water electrolyzers constructed using CoFeP @ C superlattices as both cathode and anode require a low cell voltage of 1.55 V to achieve a current density of 10 mA cm−2, outperforming most nonprecious metal‐based electrocatalysts reported previously. The superior electrocatalytic performance of CoFeP @ C superlattices is revealed by density functional theory calculations. These findings provide new opportunities for developing efficient and stable bifunctional electrocatalysts for water splitting. [ABSTRACT FROM AUTHOR]

Incorporating open architectures into a self-assembled close-packed superstructure is vital to its component exposure and hence the overall performance presented. Here, we depict a high-yield, emulsion-based assembly strategy that enables the one-step organization of preformed nanocrystals into crystalline superparticles with tunable macroporosity. We show that tuning the water/hexane ratio and/or the shearing rate during the emulsification process allows a wide-range modulation of the size and density of macropores generated within SPs. In addition, we demonstrate that the evolution of macroporosity, having negligible influence on the long-range ordering of nanocrystals, benefits the fast mass transport and superior electrochemical performance in the subsequent demonstrations for lithium storage. In addition to the single-component nanocrystals, this assembly route is also applicable to the fabrication of macroporous binary nanocrystal SPs. [ABSTRACT FROM AUTHOR]

Controlled incorporation of single atoms in a suitable host matrix can result in a radical transformation in catalytic properties. However, finding a straightforward synthetic strategy that offers a compelling combination of solution processing, atomic doping and a matching host is still a grand challenge. Here, a spontaneous heteroatom formation of atomic Zn sites in well‐defined wurtzite CoO nanorods, delivering high photoreduction rates, reaching 86.7 µmol g−1 h−1 for CO and 31.4 µmol g−1 h−1 for CH4 production is reported. Based on the validation of atomic Zn sites structures, catalytic process tracking via in situ/ex situ spectroscopic probes, and related structural simulations, a good description of the catalytic reaction kinetics for Zn/CoO as a function of applied potential is established, revealing how the single doping sites influence the CO2 photoreduction. [ABSTRACT FROM AUTHOR]

Currently, "wearable thermal‐electric harvester" is a loose term for technology that embraces rigid thermoelectric leg incorporated flexible substrates. In reality, they are not exclusively flexible, much less totally soft and stretchable. Likewise, conventional substrate‐dependent thermogalvanic cells lack the highly sought after mechanical adaptability, and hinder the full exploitation of the inherent merit of their fluidic matrices. The existence of the substrate causes poor air permeability and worse still, leads to low heat transfer efficiency. Here, a soft and stretchable thermogalvanic fabric directly woven out of p/n alternating hydrogel‐based fibers is proposed. In addition to improved wearing comfort, the compliant mechanical properties of the thermogalvanic fabric possess desired adaptability to irregular and continuously deformed skin, so as to realize conformal and efficient body heat harvesting. The scalable and modular, processable soft gel serves as the groundwork to the realization of prototypical arbitrary fabric design and potentially a new battery‐free bodily heat harvesting wearable. [ABSTRACT FROM AUTHOR]

Intrinsically self‐healing stretchable polymers have been intensively explored for soft robotic applications due to their mechanical compliance and damage resilience. However, their prevalent use in real‐world robotic applications is currently hindered by various limitations such as low mechanical strength, long healing time, and external energy input requirements. Here, a self‐healing supramolecular magnetic elastomer (SHSME), featuring a hierarchical dynamic polymer network with abundant reversible bonds, is introduced. The SHSME exhibits high mechanical strength (Young's modulus of 1.2 MPa, similar to silicone rubber) and fast self‐healing capability (300% stretch strain after 5 s autonomous repair at ambient temperature). A few SHSME‐based robotic demonstrations, namely, rapid amphibious function recovery, modular‐assembling‐prototyping soft robots with complex geometries and diverse functionalities, as well as a dismembering–navigation–assembly strategy for robotic tasking in confined spaces are showcased. Notably, the SHSME framework supports circular material design, as it is thermoreformable for recycling, demonstrates autorepair for extended lifespan, and is modularizable for customized constructs and functions. [ABSTRACT FROM AUTHOR]

Inspired by the self‐assembly of nanoparticle superlattices, we report a general method that exploits long‐chain molecular ligands to induce ordered assembly of colloidal nanosheets (NSs), resulting in 2D laminate superlattices with high packing density. Co‐assembly of two types of NSs further enables 2D/2D heterostructured superlattices. As a proof of concept, co‐assembly of Ti3C2Tx and graphene oxide (GO) NSs followed by thermal annealing leads to MXene‐rGO superlattices with tunable microstructures, which exhibit significantly higher capacitance than their filtrated counterparts, delivering an ultrahigh volumetric capacitance of 1443 F cm−3 at 2 mV s−1. Moreover, the as‐fabricated binder‐free symmetric supercapacitors show a high volumetric energy density of 42.1 Wh L−1, which is among the best reported for MXene‐based materials in aqueous electrolytes. This work paves the way toward rational design of 2D material‐based superstructures for energy applications. [ABSTRACT FROM AUTHOR]

Self-assembled nanocrystal (NC) superlattices are emerging as an important class of materials with rationally modulated properties. Engineering the nanoscale structure of constituent building blocks as well as the mesoscale morphology of NC superlattices is a crucial step in widening their range of applications. Here, we report a template-assisted epitaxial assembly strategy, enabling growth of freestanding, carbon-coated tubular monolayer superlattices (TMSLs). Specifically, we design and construct TMSLs of hollow Mn3O4 NCs (h-Mn3O4-TMSLs) by exploiting structural evolution of MnO NCs. The tubular superlattices obtained possess a number of unique and advantageous structural features unavailable in conventional NC superlattices, rendering them particularly attractive for energy conversion applications. We demonstrate this by employing h-Mn3O4-TMSLs as electrocatalysts for oxygen reduction, the catalytic performance of which is comparable to that of state-of-the-art Pt/C catalysts and superior to that of most manganese oxidebased catalysts reported. [ABSTRACT FROM AUTHOR]

Abstract: A hybrid of SnO2 nanorods interlaced by unzipped carbon nanotubes (UCNTs) was synthesized by a simple hydrothermal route. The structure and morphology of the nanocomposites were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N2 adsorption/desorption analysis. Both SEM and TEM images show that SnO2 nanorods were interlaced by UCNTs to form a network structure. The galvanostatic charge–discharge experiments showed that the reversible capacity of the hybrid was improved to 856mAhg−1 at 0.1Ag−1 and kept at 541mAhg−1 after 50 cycles at various current densities, which was higher than that of bare SnO2 nanorods. [Copyright &y& Elsevier]

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. Importantly, varying the ratio of the two components during assembly allows for accurate control over both the quantity and contact perimeter of biphasic interfaces. As a proof-of-concept demonstration, a series of Au-on-Ag superstructures with varying numbers of Au/Ag interfaces are constructed and employed as electrocatalysts for electrochemical CO2-to-CO conversion. Experimental results reveal a logarithmic linear relationship between catalytic activity and the number of Au/Ag interfaces per unit mass of Au-on-Ag superstructures. This work presents a straightforward approach for precise interface engineering, paving the way for systematic exploration of interface-dependent catalytic behaviors in heterogeneous catalysts., (© 2024 Wiley‐VCH GmbH.)

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 2 . The distinctive 2D architecture is achieved by confining the epitaxial growth of MoS 2 within the open cages of a 2D-ordered mesoporous graphitic framework (MGF), resulting in MoS 2 @MGF heterostructures with abundant sulfur vacancies. The experimental and theoretical studies establish that these MoS 2 @MGF membranes can act as a multifunctional interlayer in Li-S batteries to boost their comprehensive performance. The inclusion of the MoS 2 @MGF interlayer facilitates the trapping and conversion kinetics of LiPSs, preventing their shuttling effect, while simultaneously promoting uniform lithium deposition to inhibit dendrite growth. As a result, Li-S batteries with the MoS 2 @MGF interlayer exhibit high electrochemical performance even under high sulfur loading and lean electrolyte conditions. This work highlights the potential of designing advanced MoS 2 -encased heterostructures as interlayers, offering a viable solution to the current limitations plaguing Li-S batteries., (© 2024 Wiley‐VCH GmbH.)

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. Additionally, each branched tip is equipped with Ni-Fe particles, thereby providing numerous catalytic sites which endow them with exceptional catalytic activity for the conversion of polysulfides. The polypropylene (PP) separator modified with Ni-Fe@BCNT interlayer is fabricated as a multifunctional barrier for Li-S batteries. The experimental results demonstrate that Ni-Fe@BCNT interlayer can effectively suppress the shuttle effect of polysulfides and enhance their redox kinetics. The outstanding catalytic ability of Ni-Fe@BCNT interlayer enables batteries with high specific capacities, outstanding rate performance, and remarkable cycling stability. This approach proposed in this work paves a new path for synthesizing BCNTs and shows great potential for scaling up the production of BCNTs to address more demanding applications., (© 2024 Wiley-VCH GmbH.)

A persistent challenge in utilizing Au nanocrystals for surface-enhanced Raman spectroscopy (SERS) lies in achieving controllable superstructures that maximize SERS performance. Here, a novel strategy is proposed to enhance the SERS performance by precisely adjusting the tip arrangements of Au nanobipyramids (BPs) in two-dimensional (2D) superlattices (SLs). This is achieved through ligand-exchange of Au BPs, followed by liquid-air interfacial assembly, resulting in large-area, transferrable SL membranes. The key to controlling the arrangement of Au BPs in the SLs is the regulation of the amount of free ligands added during self-assembly, which allows for the precise formation of various configurations such as tilted SLs, tip-on-tip SLs, and tip-to-tip SLs. Among these configurations, tip-on-tip SLs exhibit the highest enhancement factor for SERS, reaching an impressive value of 1.95×10 8 , with uniform and consistent SERS signals across a large area. The experimental findings are further corroborated by simulations using the finite element method. This study establishes an efficient method for engineering the microstructure of 2D SLs composed of Au BPs, highlighting the importance of fine-tuning the tip arrangements of Au BPs to regulate SERS performance., (© 2024 Wiley-VCH GmbH.)