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Efficient and stable catalysts are crucial for green hydrogen production from acidic water splitting. Herein, using interface engineering, the surface electronic structures of bimetallic PdRu nanocubes have been significantly regulated by Pt atoms (PdRu@Pt). Interestingly, Pt atoms are located on the corners and facets of PdRu nanocubes, resulting in lattice tension and fast electron transfer. As a result, the obtained trimetallic PdRu@Pt nanocubes with an average size of 13 nm have exhibited highly enhanced catalytic activity and stability for hydrogen evolution reaction (HER) in acidic media, delivering 18 mV lower overpotential to reach a current density of 10 mA cm−2, and maintaining a remarkable long-term stability for up to 24 h. In particular, the lower overpotential of 489 mV at 500 mA cm−2 for PdRu 0.04 @Pt 0.12 nanocubes indicates its potential for future industrial application in the future. Such enhancements in HER performance can be attributed to the highly facet-edge-exposed Pt atoms and the significant strain effects resulting from the introducing Pt atomic layers to PdRu surfaces. [Display omitted] • A facile seed-mediated straightforward approach for constructing trimetallic PdRu@Pt nanocubes. • Interface engineering inducing edge-exposed Pt atoms, tailorable electronic structures, and improved strain effects. • Significantly enhanced acidic HER activity and stability with lower overpotential of 18 mV at 10 mA cm−2 [ABSTRACT FROM AUTHOR]

Within the nanoscale, methodically reconfiguring interface charges, and leveraging this newly structured interface to modify the energy-momentum dynamics of heterojunction energy bands, hold profound implications for microwave electronics because of the intensified interaction between external microwaves and interfaces of materials. Mastering the orderly reconstruction of interface charges, contingent upon precise control over composition, orientation, and electronic structure remains a challenge at this scale. Herein, an in situ hierarchical assembly approach is used to successively deposit layers of Cu2S, C, and MoS2 on a hollow cubic framework with a thickness of 20 nm. Additionally, by harnessing the quasi-graphitic characteristics and elevated work function of graphitized carbon in the middle layer, its inherent charge is steered toward both the outer and inner layers, establishing a structured configuration for the crafted Cu2S@C and C@MoS2 interfaces. Employing advanced off-axis electron holography, microwave dielectric measurements, and first-principle calculations, the dynamic reconstruction of interface charges and the resulting microwave response is ascertained. The synergistic effect revealed that the Cu2S@C@MoS2 materials exhibited exceptional microwave absorption, with an effective absorption band covering 7.03 GHz at 2.0 mm thickness. Furthermore, the orderly reconstruction of nano-interfaces paves the way for research into novel electromagnetic protection materials and their unique electronic behaviors. [ABSTRACT FROM AUTHOR]

3D nanostructured Prussian blue analogues (PBA) are promising candidates in the family of metal-organic frameworks (MOFs) for applications as bifunctional electrocatalysts due to their open framework structures, high specific surface areas and variable metal active sites. Due to their facile synthesis approach and unique framework structures, these nanostructures can be easily transformed into different structures/materials having different compositions. Herein, we have synthesized Ni–Fe Prussian blue analogue nanocubes (NiFe-PBA-NC) via a simple precipitation method and converted them into Ni–Fe Prussian blue analogue nanocages (NiFe-PBA-NG) and porous mixed metal oxide (NiFe-oxide). For the conversion of nanocubes to nanocages a very controlled etching process is carried out by using an ammonia solution while for the formation of porous mixed metal oxide, nanocubes are annealed in the presence of air. The transformation of nanocubes to nanocages and mixed metal-oxide is thoroughly characterized by various spectroscopic and microscopic techniques and employed as a bifunctional electrocatalyst for oxygen evolution and oxygen reduction reactions (OER and ORR, respectively) in which NiFe-oxide proved to be the best bifunctional catalyst. This thorough and systematic study reveals the fundamentals of the structure-property co-relation towards engineering novel bifunctional electrocatalysts. • Synthesis of NiFe-PBA-NC nanocubes and their conversion into nanocages and NiFe-oxide. • The prepared catalysts were characterized by XRD, FT-IR, XPS, TGA and FE-SEM techniques. • Investigation of role of morphology on oxygen evolution reaction (OER) and oxygen reduction reactions (ORR). • The Prepared catalysts were employed as bifunctional catalysts for OER and ORR in basic medium. • NiFe-oxide exhibit enhanced catalytic activity due to high electrochemical surface area. [ABSTRACT FROM AUTHOR]

The streamlines of the energy flux (Poynting vectors) and chirality flux as well as the intensity of the electric field around various plasmonic nanostructures (nanocube, nanocuboid, nanotriangle, hexagonal nanoplate and bowtie nanoantenna) induced by a circularly polarized (CP) or linearly polarized (LP) light were studied theoretically. The boundary element method combined with the method of moment was used to solve a set of surface integral equations, based on the Stratton–Chu formulation, for analyzing the highly distorted electromagnetic (EM) field in the proximity of these nanostructures. We discovered that the winding behavior of these streamlines exhibits versatility for various modes of the surface plasmon resonance of different nanostructures. Recently, using plasmonic nanostructures to facilitate a photochemical reaction has gained significant attention, where the hot carriers (electrons) play important roles. Our findings reveal a connection between the flow pattern of energy flux and the morphology of the photochemical deposition around various plasmonic nanostructures irradiated by a CP light. For example, numerical results exhibit vertically helical streamlines of the Poynting vector around an Au nanocube and transversely twisted-roll streamlines around a nanocuboid. Additionally, the behaviors of the winding energy and chirality fluxes at the gap and corners of a plasmonic bowtie nanoantenna, implying a highly twisted EM field, depend on the polarization of the incident LP light. Our analysis of the streamlines of the Poynting vector and chirality flux offers an insight into the formation of plasmon-enhanced photocatalysis. [ABSTRACT FROM AUTHOR]

A procedure is reported for the efficient extraction and determination of phenolics from aqueous media. The approach is based on the dispersive micro-solid phase extraction using synthesized Co3O4 nanocube-functionalized nitrogen-doped melamine foam. The adsorption and desorption conditions were optimized by response surface methodology and one-variable-at-a-time approaches. The proposed method was fully validated. Under the optimized conditions, the limits of detection were lower than 0.5 ng mL−1. Calibration curves were linear in the range from 1.0 to 250.0 ng mL−1, 0.7 to 200.0 ng mL−1, 0.2 to 250.0 ng mL−1, and 1.0 to 250.0 ng mL−1 for phenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol, respectively. Enrichment factors and absolute recoveries from 17.5 to 20.7 and 70% to 83% were achieved. The method was successfully applied for trace monitoring of the analytes in environmental and industrial water samples with gas chromatography—flame ionization detection analysis. Satisfactory relative recoveries between 89.0% and 105.8% were obtained along with acceptable precision below 8.1%. This method is a simple, rapid, sensitive, and reliable protocol for efficient screening of the phenolics. [ABSTRACT FROM AUTHOR]

A modified Co3O4 nanocube-coated melamine-derived carbon sponge was synthesized and implemented for an in-syringe micro-solid-phase extraction approach as a promising sorbent. The introduced method combined with gas chromatography–flame ionization detection has been successfully developed for the determination of naphthalene, anthracene, and pyrene in environmental water samples. Significant adsorption and desorption parameters, including sorbent amount (19.0 mg), sample pH (7.4) and flow rate (233.0 µL min−1), salt concentration (20.0%), number of adsorption (4) and desorption (4) cycles, eluent volume (425.0 µL) and its flow rate (153.0 µL min−1), were optimized by the central composite design. Under the optimal conditions, the calibration curves were linear in the range of 3.0–500.0, 1.0–250.0, and 0.8–250.0 ng mL−1 for naphthalene, anthracene, and pyrene, respectively, along with acceptable intra- and inter-day precision (≤ 8.3%). The absolute recoveries were obtained in the range of 57.4–76.6%, while limits of detection were found between 0.2 and 0.8 ng mL−1. Eventually, the proposed method was successfully applied for the determination of the studied compounds in environmental and industrial water samples with satisfactory relative recoveries between 87.5 and 104.5%. The approach minimizes organic solvent consumption, sorbent amount, and sample solution volume, resulting in reasonable sensitivity and excellent reusability. This quantitative protocol is an efficient and satisfactory analytical procedure because of its high accuracy and precision. It proved to be highly cost-effective and reliable for screening purposes. [ABSTRACT FROM AUTHOR]

It is known that heavy metal containing nanomaterials can easily prevent the formation of microbial cultures. The emergence of new generation epidemic diseases in the last 2 years has increased the importance of both personal and environmental hygiene. For this reason, in addition to preventing the spread of diseases, studies on alternative disinfectant substances are also carried out. In this study, the antibacterial activity of nanoflower and nanocube, which are easily synthesized and nanoparticle species containing iron, were compared. The antioxidant abilities of new synthesized NF@FeO(OH) and NC@α-Fe2O3 were tested by DPPH scavenging activity assay. The highest DPPH inhibition was achieved with NC@α-Fe2O3 as 71.30% at 200 mg/L. NF@FeO(OH) and NC@α-Fe2O3 demonstrated excellent DNA cleavage ability. The antimicrobial capabilities of NF@FeO(OH) and NC@α-Fe2O3 were analyzed with micro dilution procedure. In 500 mg/L, the antimicrobial activity was 100%. In addition to these, the biofilm inhibition of NF@FeO(OH) and NC@α-Fe2O3 were investigated against S. aureus and P. aeruginosa and it was found that they showed significant antibiofilm inhibition. It is suggested that additional studies can be continued to be developed and used as an antibacterial according to the results of the nanoparticles after various toxicological test systems. [ABSTRACT FROM AUTHOR]

The competition and synergy of plasmonic modes are of great importance for electromagnetic enhancement and manipulation of hot spots, enabling wide applications in plasmon-enhanced spectroscopy, photocatalysis, and photovoltaic. However, attainment of high-performance hot spots in plasmonic dimer-on-film nanocavity constitutes a challenging task. Herein, we have theoretically explored properties of hot spots in the system of Au@SiO2 nanocube dimer on Au film, and further revealed (1) large-area hot spots at the intergap between nanocubes; (2) ultrahigh-enhancement hot spots on corners of Au core; and (3) array-type hot spots at the interface between nanocubes and film. Moreover, the coupling modes have been manipulated efficiently by changing the thickness of the shell and arrangements of nanocubes. These findings inspire and guide the design of advanced nanostructures, opening opportunities for the development of devices such as photodetectors, biosensors, nanolasers, and imaging sensors. [ABSTRACT FROM AUTHOR]

The streamlines of the energy flux (Poynting vectors) and chirality flux as well as the intensity of the electric field around various plasmonic nanostructures (nanocube, nanocuboid, nanotriangle, hexagonal nanoplate and bowtie nanoantenna) induced by a circularly polarized (CP) or linearly polarized (LP) light were studied theoretically. The boundary element method combined with the method of moment was used to solve a set of surface integral equations, based on the Stratton–Chu formulation, for analyzing the highly distorted electromagnetic (EM) field in the proximity of these nanostructures. We discovered that the winding behavior of these streamlines exhibits versatility for various modes of the surface plasmon resonance of different nanostructures. Recently, using plasmonic nanostructures to facilitate a photochemical reaction has gained significant attention, where the hot carriers (electrons) play important roles. Our findings reveal a connection between the flow pattern of energy flux and the morphology of the photochemical deposition around various plasmonic nanostructures irradiated by a CP light. For example, numerical results exhibit vertically helical streamlines of the Poynting vector around an Au nanocube and transversely twisted-roll streamlines around a nanocuboid. Additionally, the behaviors of the winding energy and chirality fluxes at the gap and corners of a plasmonic bowtie nanoantenna, implying a highly twisted EM field, depend on the polarization of the incident LP light. Our analysis of the streamlines of the Poynting vector and chirality flux offers an insight into the formation of plasmon-enhanced photocatalysis.

We investigated the ferroelectric properties of barium titanate (BTO) nanocube self-assembled monolayers with and without heat treatment using piezoresponse force microscopy (PFM). Observations of polarization switching behavior confirmed that BTO nanocube monolayers about 15 nm thick are ferroelectric, even without heat treatment. Vertical PFM phase imaging of the monolayers revealed that heat treatment changed the ferroelectric polarization distribution in the monolayers at 800 °C. Atomic force microscopy and transmission electron microscopy suggested that this change originated from the residual stress caused by mechanical interactions between neighboring BTO nanocubes and between the monolayers and the substrate. [ABSTRACT FROM AUTHOR]

Oxidative transformation of indoles is a promising approach for synthesizing valuable nitrogen‐containing compounds; however, conventional methods use toxic oxidants and additives. Herein, we report for the first time the catalytic oxidative trimerization and the oxygenative cleavage (Witkop oxidation) of indoles using molecular oxygen under additive‐free conditions accomplished by a copper nitride nanocube (Cu3N NC) catalyst. The Cu3N NC catalyst exhibits excellent activity to produce various indolin‐3‐ones and 2‐ketoanilides with high functional group tolerance. Owing to this excellent catalytic performance, the Cu3N NC catalyst is distinguished from the conventional copper catalysts, demonstrating the high catalytic potential of metal nitride in organic synthesis. [ABSTRACT FROM AUTHOR]

Nanoassemblies based on drug conjugates with high drug loading efficiency and stability have been regarded as promising candidates for the next generation of drug formulations. However, they are mostly amphiphilic. Here, a dual-hydrophobic drug conjugate-based nanoassembly has been created for enhanced synergistic antiproliferation against colorectal cancer cells. Camptothecin (CPT) and doxorubicin (DOX) were chosen as the hydrophobic drugs and covalently linked with a disulfide bond (-ss-). The synthesized CPT-ss-DOX can self-assemble into nanocubes (NCs) in an aqueous solution with the assistance of a small amount of polyethylene glycol (PEG), named PEGylated CPT-ss-DOX NCs. The PEGylated CPT-ss-DOX NCs were approximately 111.8 nm, possessing a crystal structure and a very low critical aggregation concentration (8.36 μg·mL -1 ). The self-assembly mechanism was studied using molecular docking and molecular dynamic simulation methods. The NCs demonstrated excellent storage stability and improved water solubility of CPT and DOX. These NCs could be taken up by cancer cells and gradually release the drugs. In addition, they had higher toxicity to cancer cells than a mixture of CPT and DOX, while they displayed reduced toxicity to normal cells. Due to assembly and PEG modification, the NCs improved drug retention time and enhanced accumulation at the tumor site. More importantly, they significantly inhibited colorectal tumor growth (58.37%) in vivo, superior to the CPT+DOX mix (42.63%). Moreover, the NCs reduced the cardiac toxicity of free drugs. Therefore, the prepared PEGylated CPT-ss-DOX NCs hold great potential for clinical transformation and provide a novel method for the self-delivery of hydrophobic molecules in cancer therapy.

Transition metal sulfides have emerged as compelling anode materials for sodium-ion batteries (SIBs), leveraging their abundant elemental reserves and high theoretical capacities. However, the reaction of sulfur with Na ions is usually accompanied by significant volume dilation, which hinders their further development and application. Hence, constructing bimetallic sulfide (FeSn)/S for SIBs anode material greatly alleviates the circulation attenuation caused by volume expansion. Through constructing bimetallic heterojunction materials from nanocube precursors, the (FeSn)/S anode material retains a high specific capacity of 578 mAh/g at an intense current density of 2 A/g after 1000 cycles, and exhibits an great rate capability, delivering 796 mAh/g at 100 mA/g. The excellent electrochemical performance of the heterojunction material presents a promising solution to the enduring quest for enhanced anode material for SIBs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The shape and responsiveness of nanoengineered delivery carriers are crucial characteristics for the rapid and efficient delivery of therapeutics. We report on a novel type of micrometer-sized hydrogel particles of controlled shape with dual pH and redox sensitivity for intracellular delivery of anticancer drugs and phototherapy. The cubical HA-DOP-CS-PEG networks with disulfide links are obtained by cross-linking HA-DOP-CS-PEG with cystamine. The pH-triggered hydrogel swelling/shrinkage was not only affords effective doxorubicin release. It also actively provides the endosomal/lysosomal escape, redox-triggered drug release. The hydrogels degrade rapidly to low molecular weight chains in the presence of the typical intracellular concentration of glutathione. Drug-loaded cube particles found to be 12% more cytotoxic. ICG and DOX-loaded hydrogel cubes demonstrate 90% cytotoxicity when incubated with MCF-7 cancer cells for 24 and 48 h, respectively. This approach integrates the advantages of pH sensitivity, enzymatic degradation, and shape-regulated internalization for novel types of "intelligent" three-dimensional networks with programmable behavior for controlled delivery of therapeutics. [Display omitted] [ABSTRACT FROM AUTHOR]

Electrocatalysts that can sustain water splitting without corrosion are required for large-scale water electrolysis applications. Thus, designing and constructing stable electrocatalysts is known as a crucial role in hydrogen evolution reactions (HER). Herein, NiCo 2 O 4 /NiO nanocubes on Ni foam (NF) as a stable electrocatalyst were fabricated successfully by using a facile hydrothermal method. Field Emission Scanning Electron Microscopy (FESEM) confirms the formation of distinct magic NiCo 2 O 4 /NiO/NF nanocubes with a size of 50–150 nm. The electrochemical tests indicated that the NiCo 2 O 4 /NiO nanocubes possess long stability of about 140 h and exceptional HER activity with a low overpotential of 38 mV at a current density of 10 mA.cm−2 in a 1 M potassium hydroxide (KOH) and a Tafel slope of only 45 mV.dec−1. The obtained results indicated that this level of HER catalytic performance is assigned to the rough surface and synergistic interactions between Ni and Co atoms in the nanocubes. It was also determined that the existence of NiO interface layer causes robust adhesion between NF and NiCo 2 O 4 nanocubes. In addition, this discovery points to an advantageous future for the configuration and synthesis of highly effective, non-precious metal-based electrocatalysts for large-scale hydrogen production via water-splitting. [Display omitted] • A high-performance 3D binder-free NiCo 2 O 4 /NiO/NF electrocatalyst was fabricated by a two-step hydrothermal process. • The NiCo 2 O 4 /NiO/NF is composed of nanocubes morphology with edge lengths of 50–150 nm. • The NiCo 2 O 4 /NiO/NF exhibits higher activity (Ƞ 10 = 38 mV) and stability in the hydrogen evolution reaction (HER). • The improved catalytic HER efficiency is attributed to the optimized adsorption and desorption sites. [ABSTRACT FROM AUTHOR]

Strontium titanate (SrTiO 3) nanocubes were prepared via the solvothermal method in an isopropanol-water system, using cetyltrimethylammonium bromide (CTAB) as a capping agent and tert-butylamine (TBA) as a mineralizer. We found that the presence of TBA produced a synergistic effect in the nucleation and growth of SrTiO 3 in the solution, which enabled control over the formation of well-defined cubic particles. X-ray diffraction patterns of SrTiO 3 , synthesized with the addition of 1 mol of TBA, showed a perovskite structure with high crystallinity. The presence of specific absorption peaks in the fourier-transform infrared (FTIR) spectrum confirmed the existence of CTAB and TBA on the surface of the particles. Transmission electron microscope (TEM) images showed that the sharp-edged cubic particles had narrow size distributions, and selected area electron diffraction (SAED) patterns indicated a high crystallinity. An increase in electrical conductivity values was found in the bulk samples with regular nanocube particles compared to those of non-regular nanocubes. [ABSTRACT FROM AUTHOR]

Novel cube-shaped nanocrystals of BaTiO3 (BT) surrounded by CaTiO3 (CT) that can be used for piezo-driven energy harvesters were synthesized using a one-step hydrothermal reaction with surfactant and additives at 250°C for 24 h. The size distribution of the nanocubes (NCs) was narrow, with an approximate average size of 50 ~ 60 nm. The nanocubes had a core-shell configuration, such that the Pbnm structured CT shell was grown on a P4mm structured BT core by sharing corresponding [001] directions. STEM-EDX and EELS indicated that Ba ions did not diffuse into the CT shell region. Piezoelectric hysteresis loops of BT/CT NCs were obtained by piezoresponse force microscopy.

Electrochemical glycerol oxidation reaction (GLYOR) could be a promising way to use the abundantly available glycerol for production of value-added chemicals and fuels. Completely avoiding the oxygen evolution reaction (OER) with GLYOR is an evolving strategy to reduce the overall cell potential and generate value-added chemicals and fuels on both the anode and cathode. We demonstrate the morphology-controlled palladium nanocrystals, afforded by colloidal chemistry, and their established morphology-dependent GLYOR performance. Although it is known that controlling the morphology of an electrocatalyst can modulate the activity and selectivity of the products, still it is a relatively underexplored area for many reactions, including GLYOR. Among nanocube (Pd-NC), truncated octahedron (Pd-TO), spherical and polycrystalline (Pd-PC) morphologies, the Pd-NC electrocatalyst deposited on a Ni foam exhibits the highest glycerol conversion (85%) along with 42% glyceric acid selectivity at a low applied potential of 0.6 V (vs reversible hydrogen electrode (RHE)) in 0.1 M glycerol and 1 M KOH at ambient temperature. Owing to the much favorable thermodynamics of GLYOR on the Pd-NC surface, the assembled electrolyzer requires an electricity input of only ∼3.7 kWh/m 3 of H 2 at a current density of 100 mA/cm 2 , in contrast to the requirement of ≥5 kWh/m 3 of H 2 with an alkaline/PEM electrolyzer. Sustainability has been successfully demonstrated at 10 and 50 mA/cm 2 and up to 120 h with GLYOR in water and simulated seawater.

NaNbO3 particles were prepared by solvothermal synthesis at 230°C in a reaction medium of either water or methanol. Morphological control of the particles was achieved by varying the synthesis conditions, such as the starting material and the reaction medium. The starting material was prepared by a process involving heat treatment of an Nb precursor at 400°C and 800°C. The crystal structure of the starting material depended on the heat treatment temperature, with the preferred orthorhombic Nb2O5 obtained at 800°C. Large particles were obtained when water was used as the reaction medium, whereas fine particles were obtained using methanol. Under appropriate conditions, NaNbO3 nanocubes can be synthesized using orthorhombic Nb2O5 as the starting material and methanol as the reaction medium.

A nanocube is a single nanoscale crystal with a cubic shape. Raw materials are an important factor in determining the synthesis of nanocubes. In this study, we investigated various niobium compounds that serve as raw materials, each inducing different effects during nanocube synthesis. Perovskite sodium niobate (NaNbO3) nanocubes were synthesized using a two-step process. The first step in this process, synthesis of the raw materials, was followed by solvothermal synthesis of NaNbO3 nanocubes. The raw material for the first step was obtained by applying heat treatment to a precursor following Nb hydrolysis. The heat treatment was performed at temperatures of 300–1000°C. Nb2O5 was obtained after heat treatment of its precursor, during which its crystalline system morphed into hexagonal, orthorhombic, and monoclinic systems with respective increases in temperature. For the second step, we obtained various NaNbO3 morphologies via the solvothermal method using water, methanol, or ethanol as a reaction medium. NaNbO3 nanocubes were formed by applying the solvothermal method to the synthesized precursor during heat treatment at 800°C. Solvothermal synthesis was performed with methanol as the reaction medium at 200°C, which resulted in the formation of NaNbO3 nanocubes.

Noble-metal-decorated metal oxide sensors have shown promising gas-sensing properties. However, the optimal dispersion of metal particles on a semiconductor is still challenging for most sensing materials. In this study, Co3O4 nanocubes (NCs) and Pt-supported Co3O4 NCs were prepared as sensing materials for acetone gas detection. Transmission electron microscopy and X-ray diffraction were used to examine the structure and exposed facets of Co3O4 NCs. As a result, the Co3O4 NCs were identified as the single-crystalline phase of spinel Co3O4, and each surface exposed the {100} plane. To examine the cocatalytic effect of Pt combined with Co3O4 NCs on the sensing performance, Pt nanoparticles were photodeposited on Co3O4 (Pt–Co3O4 NCs). The Pt–Co3O4 NC-based sensor provided a higher p-type response than the Co3O4 NC sensor in the detection of 500 ppb acetone at 200 °C, with the highest response of 3.1 (Rg/Ra). The enhanced performance of the Pt–Co3O4 NCs is caused by the exposed {100} planes of Co3O4, in addition to the loaded Pt nanoparticles. The sensor with Co3O4 NCs has a larger neck diameter and hole accumulation layer at the interface than that with Co3O4 nanospheres and thus provides a wide channel for charge carriers, resulting in better gas-sensing responses and high selectivity toward acetone over other volatile compounds. Moreover, the Pt nanoparticles stimulate O2 dissociation on the Co3O4 surface, thus increasing the concentration of chemisorbed oxygen species by the spillover effect. Thus, the incorporation of Pt with Co3O4 NCs promotes the sensitivity of the material in the detection of acetone gas and also enhances the selectivity. This study highlights the possibility of the rapid deposition of metal nanoparticles for the improvement of gas sensors. [ABSTRACT FROM AUTHOR]

Novel cube-shaped nanocrystals of BaTiO3 (BT) surrounded by CaTiO3 (CT) that can be used for piezo-driven energy harvesters were synthesized using a one-step hydrothermal reaction with surfactant and additives at 250°C for 24 h. The size distribution of the nanocubes (NCs) was narrow, with an approximate average size of 50 ~ 60 nm. The nanocubes had a core-shell configuration, such that the Pbnm structured CT shell was grown on a P4mm structured BT core by sharing corresponding [001] directions. STEM-EDX and EELS indicated that Ba ions did not diffuse into the CT shell region. Piezoelectric hysteresis loops of BT/CT NCs were obtained by piezoresponse force microscopy. [ABSTRACT FROM AUTHOR]

A facile and cost-effective synthesis of spinel Co 3 O 4 via one-pot hydrothermal pathway with tunable morphology and size have been reported. Co 3 O 4 nanospheres synthesized in 24h shows the lowest overpotential (η) of 296 mV, much lower vis-à-vis other benchmark electrocatalysts. Electrochemical water oxidation is one of the thrust areas of research today in solving energy and environmental issues. The morphological control in the synthesis of nanomaterials plays a crucial role in designing efficient electrocatalyst. In general, various synthetic parameters can direct the morphology of nanomaterials and often this is the main driving force for the electrocatalyst in tuning the rate of the oxygen evolution reaction (OER) for the electrochemical water-splitting. Here, a facile and cost-effective synthesis of spinel cobalt oxides (Co 3 O 4) via a one-pot hydrothermal pathway with tunable morphology has been demonstrated. Different kinds of morphologies have been obtained by systematically varying the reaction time i.e. nanospheres, hexagon and nanocubes. Their catalytic activity has been explored towards OER in 1.0 M alkaline KOH solution. The catalyst Co 3 O 4 -24 h nanoparticles synthesized in 24 h reaction time shows the lowest overpotential (η) value of 296 mV at 10 mA cm−2 current density, in comparison to that of other as-prepared catalysts i.e. Co 3 O 4 -pH9 (311 mV), Co 3 O 4 -12 h (337 mV), and Co 3 O 4 -6 h (342 mV) with reference to commercially available IrO 2 (415 mV). Moreover, Co 3 O 4 -24 h sample shows the outstanding electrochemical stability up to 25 h time. [ABSTRACT FROM AUTHOR]

We report the direct growth of highly single crystalline rhenium trioxide (ReO 3) nanorods on a tungsten (W) microwire electrode via the physical vapor transport process without any catalyst. In our growth mode, ReO 3 nanocubes were initially formed on the surface of a tungsten (W) microwire electrode and further they were anisotropically grown along the [001] crystallographic direction. Furthermore, we performed the fundamental electrochemical experiments so that from cyclic voltammetric measurements, ReO 3 nanorods on a W microwire exhibit a good capacitance and Nernstian behavior for a Fe(CN) 6 3−/Fe(CN) 6 4− redox couple in 1 M KNO 3 aqueous solution, indicating a promising electrode material for electrochemical applications. Image 1 • ReO 3 nanorods were synthesized by a vapor phase transport on various substrates. • Highly single crystalline ReO 3 nanorods/W hetero-nanostructures were prepared. • ReO 3 nanorods/W hetero-nanostructures showed the enhanced electrochemical activities. [ABSTRACT FROM AUTHOR]

The morphology of hematite photoanode is a significant relevant factor in its photoelectrochemical (PEC) performance. Hematite nanowires and nanocubes as well as nanorods with intentional Sn doping were prepared by hydrothermal processes containing disparate additives. The band-gap decreases in the sequence of nanowires, nanorods and nanocubes. Compared with nanorods, nanowires show higher carrier density but a lower light absorbance. With both inhibited bulk and surface charge recombination, nanowires achieve an enhanced photocurrent. Meanwhile, it is more complicated for the charge conversion in the hematite nanocubes. Light absorption is limited due to the compact arrangement of nanocubes. Besides, nanocubes show a highly oriented (104) plane which is unfavorable to the charge conductivity. Despite the negative factors hindering its PEC performance, the extremely high carrier density in the nanocubes benefits to the distinctly enhanced photocurrent collected from the hematite samples annealed at 550 and 650 °C respectively. However, the superiority of hematite nanocubes annealed under 800 °C is restricted by the high onset potential. Still, attributed to the high surface charge transfer efficiency, the hematite nanocubes achieve the highest photocurrent among the samples at biases above 1.3 V. Electrodes made of hematite nanorods, nanowires and nanocubes annealed at 800 °C achieve a photocurrent of 1.01, 1.30 and 1.40 mA cm−2 at 1.6 V vs. RHE, respectively. Image 1 • Hematite nanorods, nanowires and nanocubes were prepared hydrothermally. • Light absorbance decreases in sequence of nanorods, nanowires and nanocubes. • Hematite nanowires show exceeding PEC performance over the typical nanorods. • Hematite nanocubes overtake nanorods and nanowires in performance at high bias. • Hematite nanorods nanocubes achieved a photocurrent of 1.40 mA cm−2 at 1.6 V vs. RHE. [ABSTRACT FROM AUTHOR]

TiO 2 nanoboxes with a hollow interior space, derived from titanium oxydifluoride (TiOF 2) nanocubes, were prepared using a two-step method, in which the TiOF 2 nanocubes acting as the precursor were first synthesized using a typical hydrothermal route. Subsequently, a second hydrothermal step was developed to prepare the TiO 2 nanoboxes. The clear phase transformation from the TiOF 2 precursor to anatase TiO 2 was confirmed using X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photo-electron spectroscopy analyses. The evolution of the morphology from a nanocube to nanobox was revealed by scanning electron microscopy and transmission electron microscopy observations. The influences of the phase and morphology on the electrorheological (ER) effect were investigated using an ER test. The ER results suggested that the ER efficiency was significantly enhanced after the second hydrothermal treatment, especially under a high external electric field strength. The enhancement in the ER efficiency was further studied using a dielectric spectrum analysis. It demonstrated that the faster response time and large permittivity difference obtained from the dielectric spectrum of TiO 2 were responsible for the improvement in the ER effect. [ABSTRACT FROM AUTHOR]

Metal oxide nanoparticles with tunable size and shape are of significant interest since these features allow tailoring their performance, functionality, and efficiency. Doping of metal oxide nanoparticles with metal cations proved to be an effective strategy for tailoring their electrical, optical, and microstructural properties. In this study, tungsten oxide (WO3) nanoparticles doped with selenium (Se) and lanthanum (La) catalysts were produced with a preferential nanocube morphology by arc discharge method. Se and La catalysts were introduced into the tungsten (W) electrode acting as an anode, and the arc-discharge was generated between two W electrodes in a deionized water medium. Structural and morphological features of the as-synthesized nanostructures were investigated by performing scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. Morphological analyses revealed that the resultant nanoparticles exhibited nanocube morphology with size ranges of 10 to 50 nm. X-ray diffraction (XRD) results proved the existence of highly crystalline monoclinic WO3 as an abundant structure. We confidently believe that the arc-discharge method can be utilized to produce various types of nanostructures with tunable size and shape by tailoring process parameters, including the type of dopant. [ABSTRACT FROM AUTHOR]

A Fano resonance is experimentally observed in a single silver nanocube separated from a supporting silver film by a thin aluminum oxide film. The resonance spectrum is modulated by changing the size of the silver nanocube and its distance from the silver film. The system is fabricated by a bottom-up process with an accurately controlled nanogap at the sub-6-nm scale. The simulation result shows that the destructive interference between the dipole mode and the quadrupole mode in this "nanocube on mirror" (NCoM) structure is responsible for the resonance. The spectra red-shifted as the size of the silver nanocube increased and its distance from the silver film decreased. In addition, a refractive index sensitivity of the spectrum of 140 meV/RIU (refractive index unit), with a 2.4 figure of merit, is obtained by changing the dielectric environment around the silver nanocube. This work will enable the development of high-performance tunable optical nanodevices based on NCoM structures. [ABSTRACT FROM AUTHOR]

Shape-controlled synthesis of multicomponent metallic nano-alloy materials is of great significance for the design and preparation of high-efficiency electrocatalysts. In this work, a simplified one-pot synthetic strategy for the preparation of uniform three-dimensional (3D) PdAg cubic nanocages (PdAg–CNC) was developed. The morphology and structure of PdAg–CNC were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). We elucidate a series of reaction pathways for the formation of various morphologies (sphere, cubic nanocage and nanowire) of PdAg alloys by tuning the amount of glycine and controlling the Pd/Ag molar ratio. The PdAg–CNC shows enhanced electrocatalytic activity, good durability and excellent methanol tolerance in comparison with commercial Pd–C and Pt–C catalysts for the oxygen reduction reaction (ORR) in alkaline medium. The excellent ORR performance of the PdAg–CNC can be correlated to the Pd–Ag alloy formation and unique mesoporous nanocage structure. This work demonstrates a facile strategy for shape-controlled synthesis of multicomponent metallic nano-alloys materials and their catalytic application. Image 1 • PdAg cubic nanocages are prepared by a simplified one-pot synthetic strategy. • Morphology of PdAg can be controlled by turning the amount of glycine and the Pd/Ag molar ratio. • PdAg cubic nanocages show enhanced electrocatalytic activity for oxygen reduction. • PdAg cubic nanocages exhibit a good electrochemical durability and a high methanol tolerance. [ABSTRACT FROM AUTHOR]

MOF (Co3[Fe(CN)6]2)-derived porous nanocube-like CoS2 is coupled with GO via solution-precipitation and chemical replacement method. Due to the proper loading and structure adjusting of CoS2, the prepared nanocomposites show a maximum specific capacitance of 842 F g−1 at 0.5 A g−1, high-rate stability (capacity retention of 77% from 0.5 up to 10 A g−1), and long-cycle life stability (capacity retention of 95% over 2000 cycles). [ABSTRACT FROM AUTHOR]

A fluorometric assay for histidine (His) is described. It is based on the inhibitory effect of His on nanocubes consisting of cobalt-containing Prussian Blue analog (CoFe NCbs), which have a strong oxidation effect on thiamine (THI) in the presence of NaOH. THI is nonfluorescent but the oxidized form (thiochrome; ThC) has a strong blue fluorescence, with excitation/emission maxima at 370/445 nm. His inhibits the oxidation effect of the CoFe NCbs due to the strong interaction between its imidazole side chain and the amino groups of the CoFe NCbs. This method is fast and has good sensitivity and selectivity. The lower detection limit is 14.3 nM of His, the linear range extends from 0.05 to 2.5 μM, and the relative standard deviation is calculated to be 1.5%. The method was successfully employed to quantify His in spiked serum samples. [ABSTRACT FROM AUTHOR]

NaNbO3 particles were prepared by solvothermal synthesis at 230°C in a reaction medium of either water or methanol. Morphological control of the particles was achieved by varying the synthesis conditions, such as the starting material and the reaction medium. The starting material was prepared by a process involving heat treatment of an Nb precursor at 400°C and 800°C. The crystal structure of the starting material depended on the heat treatment temperature, with the preferred orthorhombic Nb2O5 obtained at 800°C. Large particles were obtained when water was used as the reaction medium, whereas fine particles were obtained using methanol. Under appropriate conditions, NaNbO3 nanocubes can be synthesized using orthorhombic Nb2O5 as the starting material and methanol as the reaction medium. [ABSTRACT FROM AUTHOR]

The photoelectrical splitting of water is an important technique for the efficient generation of hydrogen using catalysts. However, understanding the effects of the size and crystallinity of catalysts is essential for tuning the efficiency of photo electrochemical hydrogen production. In this study, we synthesized WO 3 nanocubes with controlled uniform size and shape using a low-temperature hydrothermal method at various temperatures. The nanocubes obtained at a calcinations temperature of 450 °C exhibited higher crystallinity and superior photo catalytic performance during the photo electrochemical production of hydrogen via the oxidation of water in KOH solution. The band gap was determined as ∼2.54 eV with a photocurrent density of 0.0021 mA/cm2 and a flat band potential around −0.77 V. The nanocubes also exhibited good stability in the alkaline KOH electrolyte for 2 h. Therefore, the superior crystallinity of the WO 3 nanocubes could enhance the density of the charge carriers and improve the stability while also decreasing the band gap. These findings may facilitate the fabrication of a stable photo anode for large scale water splitting applications. • Shape and size controlled WO 3 nanocubes synthesized. • Physical and photoelectrochemical performance of WO 3 nanocubes assessed. • Higher photocurrent density of 0.0021 mA/cm2 achieved with 72% of IPCE. • Optimized WO 3 nanocubes calcined at 450 °C could be a useful photoanode. [ABSTRACT FROM AUTHOR]

Plasmonic nanoparticles exhibit unique properties that distinguish them from other nanomaterials, including vibrant visible colors, the generation of local electric fields, the production of hot charge carriers, and localized heat emission. These properties are particularly enhanced in the narrow nanogaps formed between nanostructures. Therefore, creating nanogaps in a controlled fashion is the key to achieving a fundamental understanding of plasmonic phenomena originating from the nanogaps and developing advanced nanomaterials with enhanced performance for diverse applications. One of the most effective approaches to creating nanogaps is to assemble individual nanoparticles into a clustered structure. In this study, we present a fast, facile, and highly efficient method for preparing core@satellite (CS) nanoassembly structures using gold nanoparticles of various shapes and sizes, including nanospheres, nanocubes (AuNCs), nanorods, and nanotriangular prisms. The sequential assembly of these building blocks on glass substrates allows us to obtain CS nanostructures with a 100% yield within 4 h. Using 9 different building blocks, we successfully produce 16 distinct CS nanoassemblies and systematically investigate the combinations to search for the highest Raman enhancement. We find that the surface-enhanced Raman scattering (SERS) intensity of AuNC@AuNC CS nanoassemblies is 2 orders of magnitude larger than that of other CS nanoassemblies. Theoretical analyses reveal that the intensity and distribution of the electric field induced in the nanogaps by plasmon excitation, as well as the number of molecules in the interfacial region, collectively contribute to the unprecedentedly large SERS enhancement observed for AuNC@AuNC. This study not only presents a novel assembly method that can be extended to produce many other nanoassemblies but also identifies a highly promising SERS material for sensing and diagnostics through a systematic search process.

The streamlines of the energy flux (Poynting vectors) and chirality flux as well as the intensity of the electric field around various plasmonic nanostructures (nanocube, nanocuboid, nanotriangle, hexagonal nanoplate and bowtie nanoantenna) induced by a circularly polarized (CP) or linearly polarized (LP) light were studied theoretically. The boundary element method combined with the method of moment was used to solve a set of surface integral equations, based on the Stratton-Chu formulation, for analyzing the highly distorted electromagnetic (EM) field in the proximity of these nanostructures. We discovered that the winding behavior of these streamlines exhibits versatility for various modes of the surface plasmon resonance of different nanostructures. Recently, using plasmonic nanostructures to facilitate a photochemical reaction has gained significant attention, where the hot carriers (electrons) play important roles. Our findings reveal a connection between the flow pattern of energy flux and the morphology of the photochemical deposition around various plasmonic nanostructures irradiated by a CP light. For example, numerical results exhibit vertically helical streamlines of the Poynting vector around an Au nanocube and transversely twisted-roll streamlines around a nanocuboid. Additionally, the behaviors of the winding energy and chirality fluxes at the gap and corners of a plasmonic bowtie nanoantenna, implying a highly twisted EM field, depend on the polarization of the incident LP light. Our analysis of the streamlines of the Poynting vector and chirality flux offers an insight into the formation of plasmon-enhanced photocatalysis.

Tailoring transition-metal oxide nanoparticles with two-dimensional carbon has become a favorite way to improve their electrochemical performance. In this study, a composite of reduced graphene oxide was anchored by Co 3 O 4 nanocubes and easily prepared with the assistance of polydopamine (PDA), using a combination of hydrothermal reaction and pyrolysis (Co 3 O 4 @PDA-rGO). Polydopamine, which possesses abundant catechol and amine groups, could be easily grafted onto graphene oxide to reduce the aggregation of graphene particles. Furthermore, PDA provided active sites, i.e., catechol and amine groups, which coordinated with Co2+, enabling enrichment of metal ions on the surface of graphene. After the pyrolysis of Co2+-containing PDA-grafted graphene at 400 °C, the Co2+ ions were converted into Co 3 O 4 nanocubes, while the PDA carbonized to form N-doped porous carbon on the surface of graphene. The resulting product, Co 3 O 4 @PDA-rGO, demonstrated extraordinary supercapacitive behavior with good cycling stability owing to its unique porous structure as well as the intimate contact between Co 3 O 4 and the carbon matrix. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (Ni3[Fe(CN)6]2)) derived nanocube‐like Ni(OH)2 was grown evenly on the surface of GO via solution‐precipitation and potassium hydroxide etching process at room temperature. Due to the even dispersion of Ni(OH)2 nancubes, the obtained sample Ni(OH)2/GO exhibits a maximum specific capacitance of 1299 F g−1 at 0.5 A g−1, excellent electrochemical stability (capacity retention of 63% from 0.5 A g−1 to 10 A g−1), and long‐cycle stability (capacity retention of 78% over 2000 cycles). [ABSTRACT FROM AUTHOR]

A nanocube is a single nanoscale crystal with a cubic shape. Raw materials are an important factor in determining the synthesis of nanocubes. In this study, we investigated various niobium compounds that serve as raw materials, each inducing different effects during nanocube synthesis. Perovskite sodium niobate (NaNbO3) nanocubes were synthesized using a two-step process. The first step in this process, synthesis of the raw materials, was followed by solvothermal synthesis of NaNbO3 nanocubes. The raw material for the first step was obtained by applying heat treatment to a precursor following Nb hydrolysis. The heat treatment was performed at temperatures of 300-1000°C. Nb2O5 was obtained after heat treatment of its precursor, during which its crystalline system morphed into hexagonal, orthorhombic, and monoclinic systems with respective increases in temperature. For the second step, we obtained various NaNbO3 morphologies via the solvothermal method using water, methanol, or ethanol as a reaction medium. NaNbO3 nanocubes were formed by applying the solvothermal method to the synthesized precursor during heat treatment at 800°C. Solvothermal synthesis was performed with methanol as the reaction medium at 200°C, which resulted in the formation of NaNbO3 nanocubes. [ABSTRACT FROM AUTHOR]

Inexpensive copper nanoparticles are generally thought to possess weak and broad localized surface plasmon resonance (LSPR). The present experimental and theoretical studies show that tailoring the Cu nanoparticle to a cubic shape results in a single intense, narrow, and asymmetric LSPR line shape, which is even superior to round-shaped gold nanoparticles. In this study, the dielectric function of copper is decomposed into an interband transition component and a free-electron component. This allows interband transition-induced plasmon damping to be visualized both spectrally and by surface polarization charges. The results reveal that the LSPR of Cu nanocubes originates from the corner mode as it is spectrally separated from the interband transitions. In addition, the interband transitions lead to severe damping of the local electromagnetic field but the cubic corner LSPR mode survives. Cu nanocubes display an extinction coefficient comparable to the dipole mode of a gold nanosphere with the same volume and show a larger local electromagnetic field enhancement. These results will guide development of inexpensive plasmonic copper-based nanomaterials. [ABSTRACT FROM AUTHOR]

The yolk-shell Fe3O4@C nanocubes were successfully synthesized through carbothermic reduction process from carbon-coated α-Fe2O3 precursor. The results show that the yolk-shell Fe3O4@C nanocubes are uniformly coated with a thin carbon layer, and a clear cavity about 150 nm in width between Fe3O4 core and carbon shell are formed due to the volume shrinkage during the reduction treatment. The obtained yolk-shell Fe3O4@C nanocubes exhibit excellent cycling stability (the discharge capacity is 709.7 mA·h/g after 100 cycles at the current density of 0.1C) and rate performance (1023.4 mA·h/g at 0.1C, 932.5 mA·h/g at 0.2C, 756.1 mA·h/g at 0.5C, 405.6 mA·h/g at 1C, and 332.3 mA·h/g at 2C, and more importantly, when the current density finally backs to 0.1C, a capacity of 776.8 mA·h/g can be restored). The outstanding lithium storage properties may be attributed to the unique yolk-shell structures. [ABSTRACT FROM AUTHOR]

Cubical crystalline 3 at% Eu 3+ ion doped BaF 2 nanomaterials have been successfully synthesized by ethylene glycol route. The cubical crystalline structure of BaF 2 was confirmed by XRD analysis. FTIR study shows the significant capping of nanomaterials by ethylene glycol. Microscopy study indicates the change of shape of nanoparticles from spherical to rod at higher annealing temperature (900 °C). Photoluminescence studies give the characteristic emission of Eu 3+ at 587 ( 5 D 0 → 7 F 1 , magnetic dipole transition) and 613 nm ( 5 D 0 → 7 F 2 , electric dipole transition). The decay time of as-prepared sample is longer than 900 °C annealed samples. The CIE chromaticity coordinates diagram shows the prepared nanomaterials can be used as orange-reddish emitter. The samples were dispersed in different organic solvents and observed that emission intensity increases with increase in chain length of the solvents. The prepared Eu 0.03 Ba 0.97 F 2 /Fe 3 O 4 nanocomposites can achieve hyperthermia temperature (HT) at short period. Nanocomposite generates more heat than pure Fe 3 O 4 nanoparticles. [ABSTRACT FROM AUTHOR]