Tailored nanoparticles: Uniform Pd icosahedra (see TEM images) were controllably synthesized in high yield by a facile polyol process. Their size can be readily tailored from 15 to 42 nm by tuning ...the reaction parameters. The high density of twin boundaries and sharp edges on the surfaces of the Pd icosahedra could make them promising for many applications, for example, catalysis.
A facile and low-cost method to prepare periodic Au@metal-organic framework （MOF） （MIL-100（Fe）） nanoparticle arrays was developed. The arrays were fabricated in situ using monolayer colloidal ...crystals as templates, followed by Au deposition on substrates, and annealing. MIL-100（Fe） coatings were applied on the nanospheres using a simple solvent thermal process. The prepared periodic Au@MIL-100（Fe） nanoparticle （NP） arrays were characterized by two peaks in the visible spectra. The first peak represented the surface plasmon resonance （SPR） of the Au nanospheres, and the other peak, or the diffraction peak originated from the periodic structure in the NP array. After modification with 3-aminophenylboronic acid hemisulfate （PBA）, the Au@MIL-100（Fe） NP arrays exhibited sensitive responses to different glucose concentrations with good selectivity. These responses could be due to the strong interaction between PBA and glucose molecules. The diffraction peak was sensitive at low glucose concentrations （less than 12 mM）, whereas the SPR peak rapidly responded at high concentrations. The peaks thus demonstrated satisfactory complementary sensitivity for glucose detection in different concentration regions. These results can be used to develop a dual-channel biosensor. We also created a standard diagram, which can be used to efficiently monitor blood glucose levels. The proposed strategy can be extended to develop different dual-channel sensors using Au@MIL-100（Fe） NP arrays agents. functionalized with different recognition
We apply a nanomanipulation technique to assemble pairs of monodispersed octahedral gold nanocrystals (side length, 150 nm) along their major axes with a varying tip-to-tip separation (25−125 nm). ...These pairs are immobilized onto indium tin oxide coated silica substrates and studied as plasmonic dimers by polarization-selective total internal reflection (TIR) microscopy and spectroscopy. We confirm that the plasmon coupling modes with the scattering polarization along the incident light direction result from the transverse-magnetic-polarized incident light, which induces two near-field-coupled dipole moments oriented normal to the air−substrate interface. In such cases, both in-phase (antibonding) and antiphase (bonding) plasmon coupling modes can be directly observed with the incident light wave vector perpendicular and parallel to the dimer axis, respectively. The observation of antiphase plasmon coupling modes (“dark” plasmons) is made possible by the unique polarization nature of the TIR-generated evanescent field. Furthermore, with decreasing nanocrystal separation, the plasmon coupling modes shift to shorter wavelengths for the incident light perpendicular to the dimer axis, whereas relatively large red shifts of the plasmonic coupling modes are found for the parallel incident light.
A capillary gradient‐induced self‐assembly strategy is developed to successfully fabricate 2D periodic Au nanosphere arrays on a centimeter‐sized scale through a bisolvent system at air/water ...interface. The bisolvent system used in this strategy consists of two steps. It first induces Au nanoparticles (NPs) floating on the water surface. Then, it compresses the sparse Au NPs into a densely close‐packed array by creating an effective capillary gradient along the water surface. This study indicates that the effects of the capillary gradient depend on water solubility and vapor pressure of a compressing solvent. A compression mechanism of capillary gradient is reasonably proposed for such self‐assembly of a densely packed monolayer on the water surface. This proposed self‐assembly strategy has advantages of having a simple operation and being environment‐friendly. The assembled Au NP arrays can provide an important and promising platform for major applications in biosensors and catalysis.
A capillary gradient‐induced self‐assembly strategy to organize monodispersed Au nanospheres into periodic dense 2D Au nanosphere arrays over a centimeter‐sized scale at the air/water interface is presented by using a bisolvent system. The presented strategy has advantages of having a simple operation and being environment‐friendly.
Although great progress has been made in hybrid iodocuprates(i) as lighting phosphors, the effects of aromatic and aliphatic structure directing agents (SDAs) on their water stability, structure and ...photoluminescence (PL) properties are still not clear. Herein, aromatic N-heterocyclic 1,2-di(4-pyridyl)ethylene (dpe), aliphatic N-heterocyclic 1,8-diazabicyclo5.4.0undec-7-ene (dbu) and N-aminoethylpiperazine (app) were selected to be SDAs to construct two types of hybrid iodocuprates(i) via a facile in situ approach. Aromatic dpe-derived cations are successfully directed to form (Me
dpe)(CuI
) (1), (Me
dpe)
(Cu
I
)
(2), (Et
dpe)
(Cu
I
) (3), and (H
dpe)
(Cu
I
)
(4). Three of them contain unprecedented inorganic iodocuprate clusters or chains. The aliphatic N-heterocyclic dbu- and app-derivative cations are responsible for the formation of (Hdbu)
(Cu
I
)
(5) and (H
app)
(Cu
I
)·2I·2H
O (6), which contain a (Cu
I
)
chain and a (Cu
I
)
binuclear cluster, respectively. For the first time, the influence mechanisms of the water stabilities of iodocuprate-based PL materials were disclosed, by analyzing the possible interactions between SDAs and water molecules. 1-2 are PL silent due to their "self-quenching effect". 3, 4 and5 exhibit bright red, orange and yellow solid-state PL emissions at room temperature respectively, originating from the charge transfer between inorganic iodocuprate species and organic N-heterocycles. The co-template approach leads to multiple charge transfers in 6, which features a tunable PL behavior from bluish green to white by varying the excitation light, and has a quantum yield up to 43% (the highest value among hybrid iodocuprates containing (Cu
I
)
clusters). The comparative study not only helps us to rationally synthesize iodocuprate-based PL materials with enhanced performance, but also provides a new method to obtain wavelength-dependent PL materials.
Using clean solar energy to reduce CO2 into value-added products not only consumes the over-emitted CO2 that causes environmental problems, but also generates fuel chemicals to alleviate energy ...crises. The photocatalytic CO2 reduction reaction (PCO2RR) relies on the semiconductor photocatalysts that suffer from high recombination rate of the photo-generated carriers, low light harvesting capability, and low stability. This review explores the recent discoveries on the novel semiconductors for PCO2RR, focusing on the rational catalyst design strategies (such as surface engineering, band engineering, hierarchical structure construction, single-atom catalysts, and biohybrid catalysts) that promote the catalytic performance of semiconductor catalysts on PCO2RR. The advanced characterization techniques that contribute to understanding the intrinsic properties of the photocatalysts are also discussed. Lastly, the perspectives on future challenges and possible solutions for PCO2RR are presented.
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Pieces of eight: Single‐crystalline Au nano‐octahedra with well‐defined shape and tunable size can be synthesized by a modified polyol process. The octahedral Au nanocrystals have sharp corners and ...display optical properties that are sensitive to the crystal sizes and the truncation of the tips.
Uniform Au nanoparticle (NP)/poly (acrylamide-co-acrylic acid) P(AAm-co-AA) hydrogel microbeads were successfully prepared using droplet microfluidics technology. The microbeads exhibited a good ...stimuli-responsive behavior to pH value. Particularly in the pH value ranging from pH 2-pH 9, the composite microbead sizes gradually increased along with the increase of pH value. The homogeneous Au NPs, which were encapsulated in the P(AAm-co-AA) hydrogel microbeads, could transform the volume changes of hydrogel into optical signals by a tested single microbead with a microspectrometre system. The glucose was translated into gluconic acid by glucose oxidase. Thus, the Au NP/P(AAm-co-AA) hydrogel microbeads were used for detecting glucose based on pH effects on the composite microbeads. For this, the single Au NP/P(AAm-co-AA) hydrogel microbead could act as a good pH- or glucose-visualizing sensor.
•BiOCl0.9I0.1/BiON catalysts are reasonably designed and synthesized via a room temperature in-situ etching method.•BiOCl0.9I0.1/BiON catalysts provide typical sample model to study heterojunction ...effect for the photodegradation of tetracycline.•Enhanced photodegradation activity due to photogenerated carriers separation and specific surface area optimized by heterojunction design.
Hierarchical heterostructures have emerged as promising candidates for the efficient photocatalytic degradation of antibiotics owing to their matched energy levels and tunable absorption bands. Herein, we report the facile synthesis of a heterojunction photocatalyst composed of basic bismuth nitrate (BiON) and BiOCl0.9I0.1 using a simple room-temperature hydrolysis method. Our results demonstrate that the BiON/BiOCl0.9I0.1 composite exhibits superior photodegradation performance compared to pure-phase materials owing to the catalytic enhancement at the heterointerface and the effective separation of the photogenerated carriers. Moreover, the unique three-dimensional microsphere morphology of the synthesized composite enhances its specific surface area and light absorption, further enhancing its photocatalytic activity. In the tetracycline (TC) photodegradation reaction as a model reaction, the catalyst could degrade 88% of TC in just 25 min. Overall, this work provides a promising strategy for the facile and low-cost synthesis of heterogeneous photocatalytic degradation materials.
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Combining thermoelectric materials with magnetocaloric materials enables a potential new all-solid-state cooling technology based on coupling enhancement of thermoelectric cooling and magnetic ...cooling, which is highly expected to achieve a technological change from thermoelectric cooling to thermoelectromagnetic cooling. However, the stability of thermal-electro-magnetic composites in service environment is still unknown. Herein, a series of Gd/BST thermo-electro-magnetic gradient composites were prepared by combining Bi0.5Sb1.5Te3（BST） thermoelectric material and Gd magnetocaloric material via spark plasma sintering technology. Evolution of phase composition, microstructure, thermoelectric, and cooling performance of the gradient composites during the 12 d aging process at 338 K and 80% relative humidity（RH） were systematically studied. The results show that the phase composition and microstructure of Gd/BST thermal-electro-magnetic gradient composites have excellent service stability. The chemical composition and average thickness（～4.5 μm） of Gd-Te diffusion layer at Gd/BST heterogeneous interface doesn't exhibit obvious change during the aging process. The test of thermoelectric and cooling performance along different Gd concentration gradient indicates that ZT of the materials negligibly changed before and after aging treatment, and the cooling temperature difference of the single-leg device is stable at about 6.5 K under the threshold current of 2.5 A. These results show that thermoelectric and cooling performance of the Gd/BST gradient composites have excellent service stability.
