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A silica supported FeCoNiCuRu high-entropy alloy (HEA) nanoparticle catalyst was prepared using a simple organic ligand chelate assisted thermal-reduction method. The organic ligand tannin is utilized to chelate Fe, Co, Ni, Cu, and Ru, facilitating the formation of HEAs with a homogeneous distribution of metal elements. The FeCoNiCuRu HEA nanoparticles are uniformly dispersed on the silica with an average size of approximately 17 nm. The formation of the HEA significantly enhances electron transfer among the individual metals within the silica supported FeCoNiCuRu catalysts. The silica supported FeCoNiCuRu HEA nanoparticle catalysts demonstrate superior hydrogenation performance for selective hydrogenation of 5-hydroxymethylfurfural, in comparison to both silica supported monometallic catalysts and their mixture. This simple organic ligand chelate assisted thermal-reduction method provides a universal strategy for generating HEA catalysts with uniform dispersion for a wide range of catalysis applications. [ABSTRACT FROM AUTHOR]

Tandem reactions are one of the effective measures for efficiently utilizing ammonia borane for organic conversion. However, in conventional reaction systems, mismatched reaction rates or too-long reaction times will cause excessive pressure in the reaction vessel, wastage of the hydrogen source, or reduction of the reaction efficiency. Therefore, higher requirements are proposed for the reaction system to utilize ammonia borane fully and rapidly for organic conversion. Herein, a novel Pickering emulsion stabilized by nanoparticles, which include emulsifying particles and hydrophilic particles, was developed as the reaction system for series-parallel catalysis. The emulsifying particles were carboxyl-modified silica nanoparticles loaded with Pd, and were endowed with pH-responsiveness, and catalysis and emulsification properties, and adsorbed at the oil–water interface of the emulsion. The hydrophilic particles were silica nanoparticles loaded with Pd and dispersed in a continuous phase. Ammonia borane released hydrogen in the water phase, while water-soluble organic matter and oil-soluble organic matter were hydrogenated in the water phase and oil phase, respectively. The reaction rates of dehydrogenation and hydrogenation were very close, resulting in efficient use of ammonia borane. The conversions of styrene and 2,5-dihydrofuran (2,5-DHF) reached as high as 95.42% and 96.08%, respectively. In addition, since the emulsions were endowed with pH-sensitivity, this enabled oil–water separation using a simple strategy. After 5 cycles, there was still a high conversion rate of organic matter. [ABSTRACT FROM AUTHOR]

Despite the wide utility of micellar palladium (Pd) nanoparticle (NP)-catalyzed Mizoroki–Heck reactions in laboratory and industrial synthesis, the easy construction of micellar Pd NPs and the detailed role of surfactants remain the focus of attention. Here, we present a simple and sustainable strategy to construct a nanoreactor by connecting micelles with Pd NPs. This strategy enables us to obtain ultrasmall Pd NPs with an average particle size of 1.8 nm, mainly in situ synthesized by triethylamine (Et3N) reduction and stabilized by chelating with sugar-based surfactant micelles. The first-order kinetic model related to the initial concentration of Pd-based catalyst is established, and the apparent activation energy of this reaction in aqueous micellar solutions is calculated to be 40.49 kJ mol−1. The mechanism of the active species ultrasmall Pd(0) NPs obtained by the reductive elimination of Pd(II) precursors by base was demonstrated. Notably, the recycled aqueous reaction mixture containing the micelles and Pd NPs can be reused. [ABSTRACT FROM AUTHOR]

The electrocatalyst for methanol oxidation is the key to determining the performance and lifetime of direct methanol fuel cells (DMFCs). At present, the most effective and promising electrocatalysts for the methanol oxidation reaction (MOR) are Pt and platinum-based catalysts. Unfortunately, the toxicity of CO intermediates leads to rapid inactivation of the MOR catalyst, further lowering the durability of the MOR. In response to this issue, it has been found that effective screening of good oxygen evolution reaction (OER) active materials and synergistic application with Pt in the MOR can reduce the loss of activity and improve its durability. Based on this strategy, a series of Pt-based MOR catalysts (Pt/Ni, Pt/Co and Pt/NiCo) are synthesized by electrodeposition. The results indicate that the OER activity of Pt/Ni, Pt/Co, and Pt/NiCo is positively correlated with MOR activity and durability. Among the Pt-based MOR catalysts, the ultimate optimized Pt/NiCo exhibits excellent MOR performance, with a good mass activity of 495 A gPt-1, strong CV cycle durability (63.6% activity retained after 5000 cycles), and a long-term operating durability of 15 000 s in alkaline solution. [ABSTRACT FROM AUTHOR]

Porous nanoparticles integrating the advantages of porosity and structural coherence typically possess numerous active sites confined on their surfaces. In this study, porous Co3O4, Fe2O3 and Fe3O4 nanoparticles are synthesised by one-step pyrolysis from metal–organic frameworks (MIL-101 (Fe) and ZIF-67 (Co)) to test the performance of CO oxidation. The prepared porous nanoparticles have uniform and stable porous structures without obvious shrinkage and structural collapse. The best catalytic performance was achieved by the porous Co3O4 nanoparticles, which reached 100% CO conversion at 130 °C without any decay in catalytic activity after 48 h of reaction. DRIFTS results present the mechanism of the CO oxidation by porous Co3O4 nanoparticle catalysis. The excellent catalytic activity of the porous Co3O4 nanoparticles is related to the large specific surface area and surface oxygen vacancies. This work provides a design approach for synthesizing other porous metal oxide nanoparticles and has reference value in the field of CO oxidation. [ABSTRACT FROM AUTHOR]

The catalysis reaction mechanism at nano/atomic scale attracted intense attention in the past decades. However, most in situ characterization technologies can only reflect the average information of catalysts, which leads to the inability to characterize the dynamic changes of single nanostructures or active sites under operando conditions, and many micro–nanoscale reaction mechanisms are still unknown. The combination of in situ transmission electron microscopy (TEM) holder system with MEMS chips provides a solution for it, where the design and fabrication of MEMS chips are the key factors. Here, with the aid of finite element simulation, an ultra-stable heating chip was developed, which has an ultra-low thermal drift during temperature heating. Under ambient conditions within TEM, atomic resolution imaging was achieved during the heating process or at high temperature up to 1300 °C. Combined with the developed polymer membrane seal technique and nanofluidic control system, it can realize an adjustable pressure from 0.1 bar to 4 bar gas environment around the sample. By using the developed ultra-low drift gas reaction cells, the nanoparticle's structure evolution at atomic scale was identified during reaction. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction to ammonia, which removes nitrates from aquatic ecosystems, is a potential alternative to the classical Haber–Bosch process. Nevertheless, the selectivity of ammonia is often affected by the toxic by-product nitrite. Here, the polyhedral-supported Cu nanoparticle binder-free monolithic electrode (Cu-BTC-Cu) is synthesized by the in situ electroreduction of Cu metal–organic framework (Cu-MOF) precursors. The Cu-BTC-Cu displays a high ammonia yield of 4.00 mg h−1 cm−2cat and a faradaic efficiency of 83.8% in 0.05 M K2SO4 (pH = 7), greatly outperforming the rod-supported (Cu-BTEC-Cu) and unsupported (Cu-BDC-Cu) Cu nanoparticle monolithic electrodes. Impressively, the Cu-BTC-Cu can inhibit significantly the release of by-product NO2− and present favourable stability after 10 consecutive cycles. These preeminent properties can be attributed to the polyhedral structure, which enables better dispersion of Cu nanoparticles and brings more active sites. Moreover, the reaction mechanism of Cu-BTC-Cu is analysed by electrochemical in situ characterization and several key intermediates are captured. This work provides new insights into the modification of the electrocatalytic nitrate reduction activity of Cu-based catalysts and ideas for the design of high-efficiency electrodes. [ABSTRACT FROM AUTHOR]

Environmental pollutants cause harm to animals, humans, and ecosystems worldwide, and powerful approaches are urgently needed to address this challenge. Dye degradation photocatalysis is one of the most promising methods for the chemical breakdown of organic pollutants. The large specific surface area produced by nanotechnology significantly improves photocatalytic performance. In the wave of full-fledged research on photocatalytic nanoparticles, there is a higher demand for unique means of characterization, such as real-time growth diagnosis and precise phase modulation of the particles. The advantages of laser spectroscopy are its non-contact methodology, rapid response, and accurate directionality, and therefore, spectral characterization methods are becoming more suitable for the real-time diagnosis of photocatalysts. In this review, traditional and spectroscopic means of characterizing dye degradation photocatalytic nanoparticles were examined. In addition, laser spectroscopic characterization can be performed using PL, LCRS, LSPR, SERS, UTAS, and LIBS, which were introduced in this review. Notably, the regulation applicability of LSPR and SERS with noble metal-based nanoparticles and the real-time flexibility of UTAS and LIBS are advantages during the use of laser spectroscopy to examine nanocomposites of photocatalysis. Moreover, the future development of laser spectroscopy for photocatalytic nanoparticle characterization was discussed. [ABSTRACT FROM AUTHOR]

The rational design and exploration of low-cost, highly efficient, and robust bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts are essential for the application of zinc–air batteries. Herein, a novel highly active and stable oxygen electrode catalyst is designed based on in situ construction of FeCo alloy nanoparticles embedded in nitrogen-doped carbon nanotubes (FeCo/N–CNTs-800) with a bamboo-like structure. The unique architecture of bamboo-like nanotubes, the large surface area with abundant mesoporous structure, and the strong coupling interactions between the encapsulated alloy nanoparticle core and the nitrogen-doped graphitic carbon shell synergistically enhance the electrocatalytic activity. As a result, FeCo/N–CNTs-800 exhibits remarkable ORR (with a half-wave potential of 0.891 V in 0.1 M KOH) and OER (with an overpotential of 359 mV to deliver 10 mA cm−2 in 1 M KOH) performance, respectively. More impressively, an assembled zinc–air battery with the bifunctional FeCo/N–CNTs-800 catalyst as the air electrode demonstrates a large power density of 200.4 mW cm−2 and robust cycling performance over 445 h compared to precious-metal catalysts Pt/C∥IrO2. Thus, the electrocatalyst presented in this work holds great potential as an air cathode for practical applications of zinc–air batteries. [ABSTRACT FROM AUTHOR]

In this work, a Ru doped CoS1.097 catalyst was synthesized by ion-exchange and one-step hydrothermal sulfuration methods. The incorporation of Ru weakens the adsorption of reaction intermediates on S sites, resulting in the improved HER electrocatalytic performance of CoS1.097 in alkaline solution. [ABSTRACT FROM AUTHOR]

Nanoscale metal–organic framework (nMOF) based nano drug delivery systems show great potential in the biomedical field. In this work, a drug delivery system combined with chemotherapy and phototherapy (DOX/ICG@UiO-66-TK-PEG-F3 or simplified as DI@UiO-TPF3) was designed for the targeted therapy of tumors. The chemotherapeutic drug doxorubicin (DOX) and the photothermal therapeutic agent indocyanine green (ICG) were loaded onto the pH-sensitive UiO-66-NH2 carrier core by physical adsorption, and the surface of UiO-66-NH2 was modified by the multifunctional polymer TK-PEG-F3 to improve the stability and targeting of the drug-loaded core. Characterizations show that the drug delivery system DI@UiO-TPF3 was successfully prepared with an excellent drug loading rate (21.6%) and photothermal conversion efficiency (32.92%). DI@UiO-TPF3 not only shows the ability to stimulate a response to release drugs, but also achieves the synergistic anti-tumor effects of chemotherapy and photothermal/photodynamic therapy (PTT/PDT), which was confirmed by in vitro evaluation. In addition, cell experiments have confirmed that DI@UiO-TPF3 connected with F3 peptide can selectively bind to the nucleolin overexpressed on the surface of tumor cells and reduce the toxicity to normal cells. Therefore, DI@UiO-UTPF3 provided a feasible strategy for constructing a targeted drug delivery platform integrating chemotherapy and phototherapy. [ABSTRACT FROM AUTHOR]

In this study, we report an efficient bifunctional electrocatalyst of rhodium telluride (RhTe2) for alkaline water splitting. With the construction of Rh–Te bonds, the catalytic performance as well as stability are boosted. [ABSTRACT FROM AUTHOR]

Red up-conversion luminescence with both emission and excitation peaks within the "tissue transparency window" makes for ideal fluorescent labels for deep tissue penetration and low-background biological imaging. In this work, an efficient strategy is proposed to realize bright red up-conversion luminescence based on interfacial energy transfer (IET), and the luminescence centers (Er3+ and Tm3+) and sensitizers (Yb3+) are doped in separate layers to avoid deleterious cross-relaxation. The IET process between Yb3+ and Er3+ can enable bright red photon up-conversion under 980 nm excitation via fine control and manipulation of the lanthanide ion concentration and shell thickness. By appropriately employing the fluorescence intensity ratio technique, an optical thermometer based on non-thermally coupled energy levels demonstrates a superior relative sensitivity of 2.02% K−1 across the whole temperature region. NaYF4:Er3+,Tm3+@NaYF4:Yb3+ with strong red UC luminescence and highly sensitive performance exhibits potential for application in the field of non-contact temperature sensing. [ABSTRACT FROM AUTHOR]

After preparing carbon-coated silver (Ag@C) nanoparticles by a one-step hydrothermal synthesis method, the surface of the nanoparticles was modified with chlorodimethyloctylsilane (C8) to generate C8 functionalized Ag@C@C8 nanoparticles. The Ag@C@C8 nanoparticles were then employed as a substrate for surface enhancement Raman scattering (SERS). The high sensitivity, good uniformity, and long stability Raman signals for both probe dyes (rhodamine 6G and crystal violet) and a real sample (malachite green) in water demonstrated good performance of the as-synthesised Ag@C@C8 nanoparticles. SEM images and TEM images indicate the successful preparation of Ag@C nanoparticles. The results of energy disperse spectroscopy, X-ray photoelectron spectroscopy and contact angle measurements all demonstrate that C8 is successfully functionalized on the surface of Ag@C nanoparticles. The combination of an agglomeration effect and the core–shell structure improves the sensitivity and stability of the substrate. The Raman performance of both Ag@C and Ag@C@C8 nanoparticles was evaluated using representative probe molecules such as rhodamine 6G, crystal violet and malachite green. The sensitivity and enhancement factor of Ag@C@C8 were evaluated using folic acid, a non-dye molecule. Additionally, malachite green in several actual water samples was also measured to evaluate the Ag@C@C8 nanoparticles. Then, using crystal violet as a probe molecule, the long-term stability of the Ag@C@C8 nanoparticles was investigated. The results indicate that for four weeks, the intensity deviations of different characteristic peaks were less than 17.5%, and there was no further downward trend. Our strategy partially overcomes the problem of easy oxidation of Ag nanoparticles by coating them with a thin carbon layer, and subsequent functionalization with C8 can increase the SERS sensitivity for certain pollutants due to a condensation effect. [ABSTRACT FROM AUTHOR]

The development of bifunctional electrocatalysts based on non-noble metals for the oxygen reduction/evolution reactions (ORR/OER) that have rationally designed structures and inexpensive components is of practical significance for the commercialization of rechargeable zinc–air batteries. Here, we report the rational synthesis of Co9S8 nanoparticles embedded in N,S co-doped hollow carbon nanosheets (Co9S8/NSC) as highly efficient oxygen electrocatalysts. The catalyst is formed when a Co-based zeolitic imidazolate framework (ZIF-67), grown on a Zn-based ZIF (ZIF-8) template, is partially vulcanized following thioacetamide (TAA) and thermal treatment. The resulting catalyst, Co9S8/NSC-3, shows satisfactory bifunctional electrocatalytic activity in 0.1 M KOH, in which the half-wave potential (E1/2) for the ORR is 0.82 V and the overpotential for the OER at 10 mA cm−2 is just 350 mV. Furthermore, as the air electrode material in a practical demonstration of a rechargeable liquid zinc–air battery, Co9S8/NSC-3 exhibits promising battery performance with a high specific capacity of 804 mA h g−1 and a pleasing charge/discharge cyclability of over 140 h at 10 mA cm−2. The satisfactory activity of Co9S8/NSC-3 can be attributed to the synergistic effect of the Co9S8 nanoparticles with the N,S-doped hollow carbon nanosheet structure, resulting in an effective electrochemically active surface with fully exposed active sites that give fast catalytic kinetics. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunction is a feature of cancer cells and targeting cancer mitochondria has emerged as a promising anticancer therapy. In this study, a novel mitochondria-targeted and ROS-responsive drug delivery nanoplatform was developed from the TPP-TK-Chlorambucil (TTCb) prodrug for effective pancreatic cancer therapy. Mitochondria targeting ligand TPP and DNA alkylating drug chlorambucil were connected by a linker containing ROS-cleave thioketal. DSPE-PEG2000 was utilized as the assisting component to increase the accumulation of nanoparticles in the tumor by the EPR effect. This smart nanoplatform showed effective mitochondrial targeting, ROS-cleaving capability and remarkable therapeutic performance in cells. The formulated nanoparticles (TTCb-NPs) rapidly revealed high cellular uptake, which demonstrated that higher accumulation in mitochondria facilitated chlorambucil targeted delivery to mitochondria where it acts on mtDNA and induces cell death. The results of in vitro antitumor activity demonstrated that the IC50 values of TTCb-NPs in three pancreatic cancer cells were around 20–30 μM, which was lower than that of chlorambucil. 50 μM TTCb-NPs could significantly inhibit the growth of BxPC3 cells. Therefore, TTCb-NPs are promising as drug delivery systems with organelle targeting and ROS-stimulated control release. These results demonstrated that the synthesized TTCb-NPs exhibited therapeutic potential for the treatment of refractory pancreatic tumors. [ABSTRACT FROM AUTHOR]

Bi2TiO4F2 nanosheets with abundant polarity surfaces make them a good candidate photocatalyst for CH4 activation. Decorated with AuPd alloy nanoparticles, highly efficient CH4 to CH3OH transformation of 277.32 μmol g−1 h−1 with 93.5% selectivity is achieved over a AuPd/Bi2TiO4F2 nanosheet photocatalyst, which is 7.4 times higher than that of the pristine Bi2TiO4F2 nanosheets. [ABSTRACT FROM AUTHOR]

Herein, we demonstrated how the processing routes of OD-Cu affected the surface structure and electrochemical reduction of CO2. We found that the OD-Cu obtained by H2 annealing is large Cu nanoparticles (>100 nm) while the OD-Cu processed by electrochemical reduction possesses a porous structure of aggregated small Cu + Cu2O nanoparticles (∼5 nm). These structural differences lead to a distinct performance. [ABSTRACT FROM AUTHOR]

Here, a poly(vinylidene fluoride) (PVDF)-based composite polymer electrolyte (CPE) with a unique Li0.33La0.56TiO3 (LLTO) nanotube filler, which shows a high Li-ion conductivity, is reported. Compared with LLTO nanoparticles (NPs) and nanowires (NWs), the LLTO nanotube fillers increase the interfacial area between PVDF and the LLTO filler, leading to the simple transportation of Li-ions through these interfacial pathways. In addition, the Li plating and stripping cycling performance of the CPEs is improved to 205 h at 0.1 mA cm−2, and the performance of the Li‖CPEs‖LiFePO4 cells also achieves a discharge capacity of 120 mA h g−1 after 100 cycles at 0.5C at room temperature. These results demonstrate an effective interfacial strategy for the design of high Li-ion conduction CPEs for all solid-state batteries. [ABSTRACT FROM AUTHOR]

Red upconversion luminescence (UCL) nanoparticles are of significant importance for applications in the fields of deep tissue imaging, photothermal therapy and security ink. In this work, a highly efficient red emission was achieved by introducing Yb3+ ions as mediators in Er3+ self-sensitized Gd2O2S nanoparticles under excitation at 1530 nm. The results show that the Gd2O2S:Yb3+,Er3+ nanoparticles synthesized by a homogeneous precipitation method exhibit a uniform spherical shape and narrow size distribution with a mean particle diameter of ≈65 nm. Moreover, the integral emission intensity ratio of red to green of the Gd2O2S:Yb3+,Er3+ sample is significantly enhanced 3-fold compared with the Gd2O2S:Er3+ sample without Yb3+ doping. The enhancement mechanisms are discussed in detail on the basis of steady-state luminescence spectra and decay dynamics measurements under various excitations at 380, 808, 980 and 1530 nm, respectively. It has been demonstrated that the enhanced red luminescence is induced by cross-relaxation energy transfer from Er3+ to Yb3via4S3/2 (Er3+) + 2F7/2 (Yb3+) → 4I13/2 (Er3+) + 2F5/2 (Yb3+) and 4I11/2 (Er3+) + 2F7/2 (Yb3+) → 4I15/2 (Er3+) + 2F5/2 (Yb3+), and further followed by back energy transfer from Yb3+ to Er3+ through 4I13/2 (Er3+) + 2F5/2 (Yb3+) → 4F9/2 (Er3+) + 2F7/2 (Yb3+). The former cross-relaxation procedure effectively populates the red emission level of 4F9/2 by depopulating the green emission level of 3S3/2. Our findings provide a feasible way to enhance the red UCL and new insights into red UCL mechanisms in the Er3+ self-sensitized system under ≈1500 nm excitation, by combining with the nontoxic oxysulfide host, indicating their potential application as safe fluorescent nanoprobes in the bio-field. [ABSTRACT FROM AUTHOR]

Dendritic mesoporous organosilica nanoparticles were synthesized under a mild acidic condition (pH 6.2), featuring a molecularly homogeneous wall structure and an unusual near-neutral charged surface, consequently enabling reduced protein fouling property. [ABSTRACT FROM AUTHOR]

Here, a new strategy is reported for the preparation of a new class of nanocomposite anode materials consisting of ppm-level phosphorus-doped Si nanoparticles (P–Si) wrapped in a network of poly-γ-glutamate and graphene. The network produces not only a conductivity-enhanced conduit but also a mechanical stress buffer. The incorporation of poly-γ-glutamate in the nanocomposite enables self-healing capability and maintains the electrode structural integrity. This multifunctionality has significant implications for advancing the design of stable Si-based nanomaterials as high-performance anodes in Li-ion batteries. [ABSTRACT FROM AUTHOR]

Developing more portable point-of-care testing tools has attracted great attention in clinical diagnostics. Though great advances have been made in the color readout-based colorimetric field, there are some limitations, due to the lower color resolution of the most naked-eye-detectable color signal. We herein propose a useful strategy for simply achieving a visually detectable temperature readout-based photothermometric assay for sensing the target analyte of alkaline phosphatase (ALP), which is based on the analyte-induced in situ generation of Prussian blue nanoparticles (PB NPs) as both colorimetric and photothermometric nanoprobe. In our design, ascorbic acid 2-phosphate is enzymatically hydrolyzed by target ALP to produce ascorbic acid in the solution reaction system, which then reduces Fe3+ to Fe2+ and further leads to the in situ formation of PB NPs via a specific reaction between potassium ferricyanide and the in situ generated Fe2+. As both colorimetric and photothermometric nanoprobe, such in situ generated PB NPs not only exhibit sensitive color change but also demonstrate a distinct temperature response that is closely dependent on the ALP content. More significantly, the limitation of low color resolution in the colorimetric system for ALP detection was successfully overcome by the proposed photothermometric method with a simple temperature readout and higher sensitivity. This approach provides a general concept with good universality, considerable simplicity and flexibility for realizing a simple thermometer-based photothermometric assay. [ABSTRACT FROM AUTHOR]

Si-based anodes are attracting enormous attention due to the super-high theoretical capacity of silicon (3579 mA h g−1 at room temperature) as an anode of lithium-ion batteries. Extensive efforts have been made to explore various composite structures to enhance the electron transmission performance throughout the anodic electrodes and improve the cycling stability. However, the obtained electrochemical reactivity of the Si anode is still limited due to the low conductivity of Si. To address this issue, we exploit a novel approach to embed highly conductive WSi2 nanodots within Si nanoparticles (WSi2/Si). In this structure, WSi2 nanodots (2–5 nm) are well-dispersed within an irregular Si matrix with a primary particle size of 30–70 nm that can facilitate the electron transport, thereby enhancing the electronic conductivity and improving the electrochemical reaction activity, and thus achieving high capacity and good rate performance. As a result, the WSi2/Si composite shows a high electrical conductivity of 1.613 S cm−1 compared with non-doped Si with 1.182 × 10−5 S cm−1. The WSi2/Si composite exhibits superior electrochemical performance, including an initial charge capacity of 2001.2 mA h g−1 at 0.84 A g−1 and a high capacity retention of 75.2% after 200 cycles. In addition, the WSi2/Si composite exhibits an excellent cycling stability of 903.4 mA h g−1 over 1000 cycles at 4.2 A g−1. Even at a high rate of 6.72 A g−1, a reversible capacity of 692.6 mA h g−1 can be maintained. Remarkably, the lithiation-induced volume change of the Si matrix is effectively alleviated due to the well-dispersed WSi2 nanodots within the Si matrix. This work could provide a valuable reference for preparing highly conductive Si via a simple and scalable method as a starting material for preparation of high performance Si-based composites. [ABSTRACT FROM AUTHOR]

Rechargeable Mg batteries are thought to be suitable for scalable energy-storage applications because of their high safety and low cost. However, the bivalent Mg2+ cations suffer from sluggish solid-state diffusion kinetics. Herein, a hollow morphological approach is introduced to design copper selenide cathodes for rechargeable Mg batteries. Hollow Cu2−xSe nanocubes are fabricated via a solution reaction and their Mg-storage properties are investigated in comparison to simple nanoparticles. The hollow structures accommodate the volume change during magnesiation/demagnesiation and maintain material integrity, and thus a remarkable cycling stability of over 200 cycles is achieved. A kinetic study demonstrates that a hollow structure favors solid-phase Mg2+ diffusion, and therefore the hollow Cu2−xSe nanocubes exhibit a high capacity of 250 mA h g−1 at 100 mA g−1 as well as a superior rate capability. Mechanism investigation indicates that Cu2−xSe experiences a structure conversion during which a phase transformation occurs. This work develops a facile method for the preparation of hollow copper selenides and highlights the advantages of hollow structures in the design of high-performance Mg-storage materials. [ABSTRACT FROM AUTHOR]

Self-assembly of colloidal nanoparticles (NPs) into superstructures offers a flexible and promising pathway to manipulate the nanometer-sized particles and thus make full use of their unique properties. This bottom-up strategy builds a bridge between the NP regime and a new class of transformative materials across multiple length scales for technological applications. In this field, anisotropic NPs with size- and shape-dependent physical properties as self-assembly building blocks have long fascinated scientists. Self-assembly of anisotropic NPs not only opens up exciting opportunities to engineer a variety of intriguing and complex superlattice architectures, but also provides access to discover emergent collective properties that stem from their ordered arrangement. Thus, this has stimulated enormous research interests in both fundamental science and technological applications. This present review comprehensively summarizes the latest advances in this area, and highlights their rich packing behaviors from the viewpoint of NP shape. We provide the basics of the experimental techniques to produce NP superstructures and structural characterization tools, and detail the delicate assembled structures. Then the current understanding of the assembly dynamics is discussed with the assistance of in situ studies, followed by emergent collective properties from these NP assemblies. Finally, we end this article with the remaining challenges and outlook, hoping to encourage further research in this field. [ABSTRACT FROM AUTHOR]

Ultrasmall CoSe2 nanoparticles encapsulated by an N-doped carbon matrix were prepared by selenizing a novel Co-metal organic framework precursor. The excellent electrochemical performance may be due to the synergistic effect of the N-doped carbon matrix and the ultrasmall CoSe2. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) tags are usually prepared by immobilizing Raman reporters on plasmonic nanoparticles (NPs) via thiol-based self-assembled monolayers. We describe here the first example of SERS tags obtained by combining gold NPs and aryl diazonium salts. This strategy results in robust Au–C covalent bonds between the Raman reporter and the NPs, thus ensuring a high stability of the nanohybrid interface. [ABSTRACT FROM AUTHOR]

Herein, a simple strategy for constructing activity-controllable nanozymes is proposed based on the glutathione (GSH)-gated surface chemistry of citrate-capped Pt nanoparticles (PtNPs). PtNPs have been shown to have oxidase-like activity that can effectively catalyze the oxidation of 3,3′,5,5′-tertamethylbenzidine (TMB) by O2, resulting in a typical color reaction from colorless to blue. We found that GSH can inhibit the oxidase-like activity of PtNPs as a molecule-gated surface chemistry element, resulting in a dramatic decrease of the oxidation of TMB. The addition of copper ions (Cu2+) could oxidize GSH into glutathione disulfide (GSSG), resulting in the distinct suppression of GSH-modulated PtNP surface chemistry and oxidase-like activity inhibition, which further results in a significant acceleration of TMB oxidation and the obvious recovery of intense blue color. Furthermore, the color-based detection signal associated with the redox of TMB indicator here was found to show good fluorescence and a photothermal effect and exhibit sensitive and selective response toward the proposed molecule-gated surface chemistry and Cu2+ target. On the basis of this phenomenon, we successfully constructed a three-in-one sensor for Cu2+ with a triple signal readout, colorimetric, photothermal (temperature), and fluorescence, depending on the proposed in situ modulation method for PtNP catalysis. The applicability of the three-in-one sensor was also demonstrated by measuring Cu2+ in human serum with a standard addition method, and the results are of satisfactory accuracy as confirmed by ICP-MS measurements. [ABSTRACT FROM AUTHOR]

An efficient signaling on–off mechanism was first proposed by integrating exciton–plasmon coupling and exciton energy transfer into cathodic PEC bioassays. This signaling on–off mechanism has endowed the cathodic PEC biosensor with powerful capability for ultrasensitive and specific detection of target DNA. [ABSTRACT FROM AUTHOR]

Ultrafine (5 nm) cobalt nitride nanoparticles supported on carbon nanotubes (CoN/CNT) are reported as air electrodes for rechargeable zinc–air batteries (ZABs). CoN/CNT exhibits 2.4 fold higher battery performance than commercial Pt/C-IrO2. [ABSTRACT FROM AUTHOR]

W/W2C heterostructured nanoparticles encapsulated by N,P dual-doped carbon (W/W2C@NPC) fabricated by the carbonization of in situ polymerized polyaniline (PANI) and phosphotungstic acid require low overpotentials of 55 mV and 82 mV vs. RHE to achieve a cathodic current density of 10 mA cm−2 in acidic and alkaline electrolytes, respectively. [ABSTRACT FROM AUTHOR]

Here, we report a facile method to synthesize ruthenium phosphides with diameter 1 nm and an amorphous structure at room temperature. Only 31 mV vs. RHE overpotential is required to deliver 10 mA cm−2 and no degradation in hydrogen evolution reaction (HER) performance is recorded after 24 h of catalysis at 100 mA cm−2. [ABSTRACT FROM AUTHOR]

Using the sol–gel technique, Ca7(VO4)4O nanoparticles with various doping concentrations of Eu3+ ions were achieved. With an excitation wavelength of 462 nm, the as-synthesized compounds can emit visible red light, which exhibited a high color purity of 82.8%, arising from the 4f–4f transitions of Eu3+ ions. The emission intensity of the Eu3+ ions in the Ca7(VO4)4O host lattices was sensitive to the dopant content with an optimum value of 10 mol%. The critical distance for the Eu3+ ions in the Ca7(VO4)4O host lattices was 32.64 Å, and dipole–dipole interactions resulted in the concentration quenching effect. By employing the Judd–Ofelt theory, the optical transition intensity parameters of the Eu3+ ions were calculated and the values of Ω2 and Ω4 were determined to be 2.81 × 10−20 cm−2 and 0.54 × 10−20 cm−2, respectively. The thermal stability of the resultant nanoparticles was verified by the temperature-dependent emission spectra, and the activation energy was determined to be around 0.47 eV. Additionally, the developed light-emitting diode device, which contained a blue chip, commercial Y3Al5O12:Ce3+ yellow-emitting phosphor and the prepared nanoparticles could emit visible white light with satisfactory colorific behavior; it had a proper color rendering index (76.5) and a low correlated color temperature (5435 K). [ABSTRACT FROM AUTHOR]

A comprehensive understanding of how the molecular structure influences the electronic coupling is crucial in optimizing (supra) molecular assemblies for photoinduced electron transfer. Here, we report that the electronic coupling underlying electron transfer from a phenothiazine donor to a photoexcited Ru(tpy)2 acceptor is modulated by substitution of the second (remote) tpy-ligand. [ABSTRACT FROM AUTHOR]

An aluminum anode with pre-constructed two-layer conductive buffers was prepared to restrict the expanding Al–Li alloy inside, and provide continuous electron pathways for promising electrical contact. The full cell demonstrates superior cycling stability (0.0352% capacity decay per cycle for 400 cycles at 0.2C) and outstanding rate capability. [ABSTRACT FROM AUTHOR]

Herein, we report a facile, efficient and versatile method for the photo-regulation of pH-dependent activities of artificial enzymes by incorporating flash photolysis reagents. Under light excitation, a persistent pH shift is achieved by proton release from photosensitive 2-nitrobenzaldehyde. Following such change, the controlled activation of oxidase-like activity of nanoceria is successfully demonstrated. [ABSTRACT FROM AUTHOR]

A novel magnetic nanoparticle supported acid–base bifunctional catalyst was synthesized by anchoring [3-(2-aminoethyl)aminopropyl]triethoxysilane and sulfonic acid successively onto the surface of silica-coated Fe3O4 nanoparticles. The as-prepared nanoparticle catalyst was used as a “quasi-homogeneous” and recyclable catalyst for the one-pot deacetalization–Knoevenagel tandem reaction of benzaldehyde dimethylacetals and malononitrile. It showed high catalytic activity because the reaction proceeded smoothly and afforded benzylidenemalononitriles in excellent yields. Besides, it showed synergistic effect and facilitated the mass transfer process during the tandem reaction because the two catalytic moieties were connected together on the same MNP. Moreover, the catalyst can be readily recovered under an external magnetic field and reused without any significant loss of the catalytic activity after six runs. [ABSTRACT FROM AUTHOR]

A spatially confined reduction strategy for the fabrication of small nanoparticles in a micro-box is reported, where iron nanoparticles with uniform diameter are highly distributed in a carbon matrix and surrounded by a mesoporous silica layer. Due to their unique confined nanostructure, the Fe/C@mSiO2 capsules could effectively remove and recycle Se(iv) from a low concentration solution. [ABSTRACT FROM AUTHOR]

We demonstrate that changing the backbone between peptides, peptoids and the underexplored dual N/Cα-substituted peptoids analogues allows for control over the preferred conformation of the intrinsically disordered biomimetic oligomers. The conformation tunability is directly probed using electron paramagnetic resonance (EPR), and is shown to manifest itself in differences in the nanoparticle–oligomer hybridization propensity. [ABSTRACT FROM AUTHOR]

Ru nanodendrites composed of ultrathin fcc/hcp nanoblades were synthesized by a facile solvothermal reduction of Ru3+ together with Cu2+ followed by selective etching of Cu, resulting in a micro/mesoporous electrocatalyst that is highly efficient and stable for the hydrogen evolution reaction in alkaline media and outperformed commercial Pt/C at a lower cost. [ABSTRACT FROM AUTHOR]

N-Doped carbon dots (CDs) were directly synthesized with a high yield of 21.85% by one-pot pyrolysis of a gel composed of ethanolamine and 1-carboxyethyl-3-methylimidazolium chloride at 220 °C for 2 h. The as-synthesized CDs with a mean particle size of 7.8 nm were uniform, amorphous, and abundant in nitrogen content (23.15 wt%) and surface groups such as amide and hydroxyl. Thus, the CDs exhibited good water-solubility, bright blue excitation- and pH-dependent fluorescence with a quantum yield of 17.93%, and high ionic strength tolerance. In addition, a CD-based fluorescent sensor towards Cr(vi) ions with favorable sensitivity and selectivity was constructed based on the inner filter effect. Two good linear relationships between the concentration of Cr(vi) ions and the PL quenching efficiency were obtained in the ranges from 0.2 to 2 (R2 = 0.9965) and 2–40 μM (R2 = 0.9918), and the limits of detection (LOD = 3σ/S) were calculated as 0.018 and 0.25 μM, respectively. Importantly, this sensor was solid and capable of rapidly detecting Cr(vi) ions in tap water with detection ranges of 0.2–2 (R2 = 0.9817) and 2–60 μM (R2 = 0.9902), LODs of 0.048 and 0.40 μM, and recoveries of 102.1–106%. [ABSTRACT FROM AUTHOR]

A new strategy for the synthesis of luminescent copper nanoclusters (Cu NCs), by virtue of the reduction of Cu2+ using ascorbic acid and the protection of polyvinylpyrrolidone at 75 °C, was reported. Blue emitting Cu NCs with photoluminescence (PL) quantum yield of 12% and high stability up to at least 1 month were obtained. Moreover, the PL of Cu NCs showed a reversible response to temperature, and a linear relationship between PL intensity and temperature even after 10 cycles of repeated heating and cooling process was obtained, indicating great potential application in thermal sensors. [ABSTRACT FROM AUTHOR]

Electrocatalytic conversion of carbon dioxide (CO2) has been considered as an ideal method to simultaneously solve the energy crisis and environmental issue around the world. In this work, ultrasmall Cu nanoparticle interspersed flower-like MoS2 was successfully fabricated via a facile microwave hydrothermal method. The designed optimal hierarchical Cu/MoS2 composite not only exhibited remarkably enhanced electronic conductivity and specific surface area but also possessed improved CO2 adsorption capacity, resulting in a significant increase in overall faradaic efficiency and a 7-fold augmentation of the faradaic efficiency of CH4 in comparison with bare MoS2. In addition, the Cu/MoS2 composite had superior stability with high efficiency retained for 48 h in the electrochemical process. It is anticipated that the designed Cu/MoS2 composite electrocatalyst may provide new insights for transition metal sulfides and non-noble particles applied to CO2 reduction. [ABSTRACT FROM AUTHOR]

A kit-like 18F-fluorination method has been successfully applied to prepare an activatable probe 1 with good radiochemical yield and high specific activity. The probe has good in vitro stability and favorable cell membrane permeability. A controlled condensation reaction was initiated, and self-assembly into nanoparticles occurred when the probe was in a reducing environment. Positron emission tomography (PET) imaging of the biothiol level in living subjects was conveniently and precisely realized using this probe. The present study may provide a new platform for the development of “smart” PET tracers for tumor imaging. [ABSTRACT FROM AUTHOR]

In this work, we have fabricated a new dual-emission quantum dot (QD) nanohybrid for fluorescence ratiometric determination of cadmium ions (Cd2+) in water samples, where the “turn-on” model and “ion-imprinting” technique were incorporated simultaneously. The nanohybrid probe was composed of green-emitting CdSe QDs covalently linked onto the surface of silica nanoparticles embedded with red-emitting CdTe QDs. The chemical etching of ethylene diamine tetraacetic acid (EDTA) at the surface produced specific Cd2+ recognition sites and quenched the green fluorescence of outer CdSe QDs. Upon exposure to different amounts of Cd2+, the green fluorescence was gradually restored, whereas the inner red fluorescence remained constant. As a consequence, an obviously distinguishable fluorescence color variation (from red to green) of the probe solution was observed. Under the optimized conditions, the developed ratiometric sensor displayed a linear response range from 0.1 to 9 μM with a detection limit of 25 nM (S/N = 3) for Cd2+, which could offer an alternative sensing approach for the highly sensitive and selective detection of heavy metal ions. [ABSTRACT FROM AUTHOR]

The hydrothermal synthesis of VO2 (M) nanoparticles is commonly considered as a result of the transformation of intermediate phase VO2 (A) or VO2 (B). Here, we found a new intermediate phase (NH4)2V4O9 that appeared in the hydrothermal synthesis and played a crucial role in the formation of VO2 (M) nanoparticles. Then, the mechanism for the transformation of intermediate (NH4)2V4O9 to VO2 (M) was described as a self-assembly–decomposition–nucleation–growth process. Pure crystalline VO2 nanoparticles were ultimately obtained and showed excellent thermochromic properties. The phase-transition temperature Tc of VO2 (M) nanoparticles is approximately 65 °C. Furthermore, VO2 flexible foils on PET at a VO2 solid content of 1.5–2.0% show excellent optical properties with luminous transmittance (Tlum) ＞ 50% and solar energy modulation ability (ΔTsol) ＞ 15%. [ABSTRACT FROM AUTHOR]

A new α-cyanostilbene derivative, CDB-DMA12, was designed and synthesized as a supramolecular chemosensor for the detection of sodium houttuyfonate (SH) via aggregation-induced emission enhancement (AIEE), which could efficiently bind with SH, then induce an obvious fluorescence enhancement and visible absorption red-shifting (by the naked eye). Accordingly, a linear relationship was found when plotting the fluorescence intensity at 558 nm against SH concentration, with an estimated detection limit of 8.5 μM. Interestingly, morphology changes from nanoparticles to sheet, scroll and tube-shaped aggregates were observed on CDB-DMA12 after the addition of SH. Moreover, CDB-DMA12 showed high selectivity to SH among other sulfonyl containing species, which is attributed to the synergistic effect of its quaternary ammonium, the hydrogen bonding of the active group sites and the twelve carbon containing long-aliphatic chain units. In addition, the results paved a new way for the detection/recognition of amphiphilic natural products in aqueous solution with high sensitivity and selectivity. Besides, it provided a possible approach for the preparation of new fluorescent micro/nano-scaled architectures through the solution self-assembly of oppositely-charged amphiphiles. [ABSTRACT FROM AUTHOR]

Star-shaped VO2 (M) nanoparticles were synthesized by hydrothermal reaction using only ammonium metavanadate and formic acid combined with subsequently mild annealing treatment. Enhanced thermochromic performance was demonstrated upon changing the temperature and the applied pulse voltage for the star-shaped VO2 (M) nanoparticle thin films. [ABSTRACT FROM AUTHOR]