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During sonar detection, the fuzzy function of hyperbolic frequency modulation (HFM) in the waveform of active signal is in the shape of a "oblique blade," which leads to the coupling characteristics of its fuzzy function in the time dimension and frequency dimension. Doppler causes a frequency shift in the frequency dimension and a time delay in the time dimension, which makes it impossible for a single HFM signal to measure speed accurately. However, the time delay caused by the same moving target to HFM signals with different frequency bands and different pulse widths is also different. A velocity measurement method combining HFM signals (VCH) is proposed, which employs the time delay correlation between the combined HFM signals to achieve the target distance and speed. In the VCH method, the echo signal is no longer matched and filtered as a whole but is divided into two channels and matched and filtered separately. And then, the combined HFM signals are used to obtain the distance and speed of the target. Extensive simulation results show that the proposed method can estimate the distance and speed of moving targets accurately, and it has reference value for engineering application. [ABSTRACT FROM AUTHOR]

The channel in the marine environment is a time-varying and space-varying channel. Pulse-truncated continuous wave (PCW) speed measurement is often used in sonar, but the instability effect of PCW signal in the channel limits the effectiveness of speed measurement. Hyperbolic frequency modulation (HFM) signal is insensitive to Doppler; therefore, HFM signals are widely used in ranging and velocity measurement of sonar and radar. However, due to the filtering effect of the marine environment, the HFM signal of a single frequency band may cause excessive transmission loss, and the echo energy may be too weak to detect the target. Based on the analysis of the influence of speed on the distance measurement of HFM signal, a pulse sequence method based on HFM for speed measurement (PHS) is proposed, which uses HFM signals of different frequency bands and pulse widths in the pulse sequence to perform speed measurement. Extensive simulation results show that PHS method not only guarantees the speed measurement but also makes full use of the energy of the HFM sequence to improve the accuracy of the distance measurement. And PHS method is valuable to the practical application of engineering. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) Ag/ZnO assemblies with porous nanosheets as building blocks have been designed and selectively prepared via a facial solution method followed by topological morphology conversion with low temperature calcination. The samples were characterized thoroughly by using XRD, SEM, TEM, HRTEM, N 2 isotherms, UV–vis spectroscopy, PL, EIS, Mott-Schottky plots, and photocurrent response. The as-prepared 3D Ag/ZnO architectures were evaluated as photocatalysts for hydrogen evolution and organic pollutants removal from aqueous solution, which demonstrates superior sun-light driven photocatalytic activities to those of ZnO architectures. Nearly 100% photocatalytic degradation of 10 ppm 4-nitrophenol was obtained just for 25 min and 0.4436 mmol g −1 h −1 of hydrogen production rate was achieved over Ag/ZnO architectures. The photocurrent of the Ag/ZnO photoelectrode showed an enhancement of three times of ZnO architectures. The enhanced photocatalytic activity may be attributed to the synergetic effect between 2D ZnO porous single crystalline nanosheets and sliver components, which could not only accelerate separation and migration efficiency of charge carries, but also enhance charge-collection efficiency. [ABSTRACT FROM AUTHOR]

Synthetic protocols to generate well-integrated frameworks of known composition are important for the rational design of advanced materials. 3D CeO2/NiO hierarchical assemblies were designed and constructed with 2D CeO2/NiO heterostructures as building blocks consisting of NiO nanosheets wrapped with CeO2 ultrathin nanosheets on the surfaces. The growth process of the 2D CeO2/NiO heterostructure nanosheets and the 3D assemblies was described based on a domain-matching growth process. The CeO2/NiO assemblies exhibited superior catalytic properties for CO oxidation. A model of the structure–property relationships based on surface and interface structures is discussed. [ABSTRACT FROM AUTHOR]

In this study, a series of PbS polyhedra were synthesized through hydrothermal decomposition of the as-formed lead diethyldithiocarbamate (Pb-DDTC) single-source precursor in its precursor solution. Through extensive experiments, it was concluded that the amount of poly-(vinylpyrrolidone) (PVP), DDTC and the reaction time had major effects on the shapes of the as-synthesized PbS crystals. Sub-micro sized cuboctahedrons and cubes were selectively obtained by manipulating the concentration of PVP and the reaction time. Possible growth mechanism for the shape controlled synthesis of PbS crystals was briefly discussed. [ABSTRACT FROM AUTHOR]

Abstract: Well-dispersed α-Fe2O3 parallelepiped nanocrystals have been successfully prepared via a hydrothermal synthetic route. The shapes and structures of the products were characterized by using powder X-ray diffraction and scanning electron microscopy. The results showed that the α-Fe2O3 samples have a parallelepiped shape with an average parallel side of 80–90nm and thickness of 60–70nm. The parallelepiped nanocrystals exhibited a ferromagnetic behavior with the coercive force, saturation magnetization, and remanent magnetization of 920Oe, 0.44emu/g, and 0.17emu/g, respectively. The crystal growth process was discussed on the basis of time-dependent experimental results. [Copyright &y& Elsevier]

A series of Bi2S3microstructures, including crepe paper flower-like structures, multibranched nanobelts, actinomorphic-flower-like 2-D assembled nanowire arrays, straw-tied-like nanowire arrays, and nanowires have been synthesized through facile decomposition of the as-formed bismuth diethyldithiocarbamate (Bi-DDTC) single-source precursor in its precursor solution. The morphologies and concentration and site of structure defects of the Bi2S3microstructures can be controlled by manipulating the concentration of Bi/DDTC and the reaction time. Possible growth mechanisms involving defect effects, oriented attachment and folding–splitting–attaching growth were proposed, which were responsible for morphology and structure evolution of various Bi2S3microstructures. [ABSTRACT FROM AUTHOR]

Abstract: A facile one-pot synthesis of ZnS hollow spheres has been carried out via a chemical transformation induced inside-out Ostwald ripening process from a single source precursor. The size and shell thickness of the ZnS hollow spheres can be controlled by adjusting the reaction temperature and reaction time, respectively. Photoluminescence spectra show a dominant emission peak at 470nm accompanied by several weaker peaks. UV–vis measurement reveals that the obtained ZnS hollow spheres exhibit “hollow effect”. The formation process of ZnS hollow spheres has been discussed. [Copyright &y& Elsevier]

Uniform cubic-shaped PbTe and PbSe nanocrystals have been synthesized through the surfactant-assisted hydrothermal reaction between Pb(NO3)2 and Te or Se powders with hydrazine hydrate as reducing reagent. The products were characterized by powder x-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that the shapes of nanocubes are well controlled by using ethylenediaminetetraacetic acid as chelating reagent and in the presence of poly(vinyl-pyrrolidone). [ABSTRACT FROM AUTHOR]

Abstract: ZnO whisker arrays have been prepared by a self-source procedure of the substrate under hydrothermal conditions. Zinc foils were used as a substrate and zinc-ion source for direct growth of ZnO whiskers. SEM observations revealed that the as-prepared ZnO whiskers exhibit hexagonal prism-like shape showing well-defined crystallographic facets and hexagonal pyramid-like sharp tips. The growth of ZnO whiskers in the initial stage has been recorded, and the growth mechanism was discussed in detail. [Copyright &y& Elsevier]

Abstract: Anatase titania hollow spheres have been successfully prepared using styrene-acrylic acid copolymer (PSA) latex particles as template, which involves the deposition of inorganic coatings on the surface of PSA latex particles and subsequent removal of the latex particles by calcinations in air. Ti(SO4)2 instead of organometallic titanium was firstly used as precursor for the preparation of titania hollow spheres. The formation of anatase titania was confirmed by XRD analysis and the hollow structure of the samples was revealed by electron microscope. [Copyright &y& Elsevier]

Abstract: One-dimensional Sb2S3 and Sb2Se3 crystals with straw-tied-like architectures have been successfully prepared in high yield by a one-pot hydrothermal method using water-soluble potassium antimony tartrate as antimony source. X-ray powder diffraction results and electron diffraction (ED) analysis show that the Sb2S3 wires and Sb2Se3 rods have a preferential growth direction along their c-axis. The peculiarities of the one-dimensional (1-D) growth mechanism are discussed. [Copyright &y& Elsevier]

ZnO nanorod and nanoprism arrays have been directly synthesized on a large-area zinc substrate via a convenient solution method. The products were characterized with XRD, SEM, HRTEM, and photoluminescence (PL) spectroscopy. The influence of the solvent and the concentration of NaOH on the size and shapes of the as-prepared ZnO samples have been studied. It was found that ZnO nanorod or nanowire arrays were fabricated in alcohol, whereas ZnO nanoprisms with pyramid tips were produced in an alcohol−water mixture. The diameters of the nanorods or nanoprisms became thicker when a higher concentration of NaOH was used. Room-temperature PL spectra of the ZnO products showed a UV emission and a broad green band. The mechanism of the nanorods and nanoprisms in two systems is briefly discussed. [ABSTRACT FROM AUTHOR]

Abstract: Flake-like silver nanoparticles have been synthesized in large quantity by simply aging the aqueous solution of silver and urotropine in the presence of poly-(vinylpyrrolidone) (PVP). Silver nanoflakes of different shapes from circular to polygonal could be obtained in different reaction stages. PVP molecules play an important role in the anisotropic growth of silver nanoflakes. The as-synthesized silver colloidal solution remained stable for at least 1 month. Electron diffraction analysis showed that the nanoflakes are well crystallized. The UV-VIS absorption properties have also been studied. [Copyright &y& Elsevier]

Abstract: Fe2O3 microcages, with uniform size and diameters of about 620 nm, have been successfully prepared by templating against styrene-acrylic acid (PSA) copolymer latex particles, which involves the deposition of Fe(OH)3 coatings on the surface of latex particles and subsequent removal of the latex particles by calcinations. The cage-like structure of the samples was revealed by scanning electron microscope (SEM), and the formation of Fe2O3 was confirmed by X-ray powder diffraction (XRD) analysis. The porous shells were constructed with Fe2O3 nanoparticles, and the shell thickness is of 30–60 nm, matching the diameters of the Fe2O3 nanoparticles. [Copyright &y& Elsevier]

Silver nanoshells on styrene–acrylic acid copolymer latex spheres (PSA) were deposited by an in situ chemical reduction method, ageing a colloid solution at 85 °C containing PSA latex, AgNO3, urotropine, and poly-(vinylpyrrolidone). SEM and TEM observations showed that the silver nanoshells were made of closely packed silver nanoparticles of different sizes and morphologies. UV–visible absorption spectra were recorded to investigate their optical properties. [ABSTRACT FROM AUTHOR]

Silver-coated poly(methyl acrylic acid) (PSA) core–shell colloid particles were prepared by an in situ chemical reduction method. Crystalline silver/titania composite hollow spheres were obtained by coating the as-prepared PSA/silver particles with an amorphous titania layer and subsequently calcining in Ar atmosphere. SEM and TEM investigation indicated that the size of the as-prepared PSA/silver and PSA/silver/TiO2 core–shell particles and silver/titania composite hollow particles was fairly uniform and the wall thickness of the hollow spheres was in the range of 40–80 nm. UV–vis absorption spectra were recorded to investigate their optical properties. [Copyright &y& Elsevier]

CdS hollow spherical particles with average diameter of 800 and 850 nm have been prepared using core/shell fabrication method with poly-(styrene-acrylic acid) (PSA) latex particles as template. TEM images show that smoothly coated core/shell composite particles have been fabricated by multicycles of coating in optimum concentration of reactants. CdS hollow spheres were obtained after removing the template by dissolving the polymer in the organic solvent, and the wall thickness is about 40–100 nm. [Copyright &y& Elsevier]

Main group Bi‐based materials have gained popularity as N2 reduction reaction (NRR) photo/electrocatalysts due to their ability to inhibit competitive H2 evolution reactions (HER) and the unique N2 adsorption activities. The introduction of defects in Bi‐based catalysts represents a highly effective strategy for enhancing light absorption, promoting efficient separation of photogenerated carriers, optimizing the activity of free radicals, regulating electronic structure, and improving catalytic performance. In this review, we outline the various applications of state of the defect engineering in Bi‐based catalysts and elucidate the impact of vacancies on NRR performance. In particular, the types of defects, methods of defects tailoring, advanced characterization techniques, as well as the Bi‐based catalysts with abundant defects and their corresponding catalytic behavior in NRR were elucidated in detail. Finally, the main challenges and opportunities for future development of defective Bi‐based NRR catalysts are discussed, which provides a comprehensive theoretical guidance for this field. [ABSTRACT FROM AUTHOR]

Abstract: CdS microspheres with hierarchical structures were prepared with sodium dodecylbenzenesulfonate (SDBS) as structure directing reagent. SEM analysis indicated that the CdS microspheres were constructed with CdS nanosheets, which were further built up with assembled CdS nanoparticles. Optical investigation showed that the obtained CdS microspheres have an UV–vis absorption at 445nm and photoluminescence (PL) emissions at 498 and 573nm. The CdS hierarchical microspheres were immobilized on a glassy carbon electrode and the electrochemiluminescence (ECL) properties were investigated. The first application to sensing H2O2 was studied based on ECL from CdS hierarchical microspheres. A linear relation between the ECL intensity and H2O2 concentration, I =2.4212+2.1713 c, was obtained with a detection limit of 1×10−8 mol·L−1. [Copyright &y& Elsevier]

Abstract: This paper describes a one-pot surfactant-assisted hydrothermal method for the synthesis of Ag-TiO2 composite hollow structures with high photocatalytic activity. TEM measurement reveals that the sample is composed of hollow spheres and their tube-like aggregates. The surfactant cetyltrimethylammonium bromide (CTAB) plays a key role in the construction of the Ag-TiO2 hollow structures. The Ag-TiO2 hollow structures showed effective photocatalytic activity for the decomposition of methyl orange. [Copyright &y& Elsevier]

Abstract: In this paper, we developed a facile low-temperature solution route to prepare radical-shaped ZnO microprisms and to deposit metal silver on the surface of ZnO to form Ag/ZnO microstructures. The samples were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. Experimental results show that the deposition of metal Ag nanospecies can be achieved successfully by simply aging the solution at 75°C, and the radical-shaped microstructures of ZnO are well maintained. The Ag/ZnO microstructures exhibit much lower PL emission intensity and much higher photocatalytic activity than those of radical-shaped ZnO microprisms. [Copyright &y& Elsevier]

Mono-dispersed Mg(OH)2 nanoflakelets have been prepared with the assistant of 4-(p-nitrophenylazo)resorcinol. The samples were characterized using XRD, TEM, and ED. Electron diffraction analysis showed that single crystalline nanoflakelets were obtained in hydrothermal process, and porous Mg(OH)2 nanosheets were prepared at lower temperature. Nitrogen adsorption isotherms show that the surface area of Mg(OH)2 nanosheets is 129 m2/g. Possible growth mechanism of the nanoflakelets is discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] The emerging S-scheme heterojunction shows a particular superiority in enhancing the efficiency of charge separation in photocatalyst. Herein, a Ni 11 (HPO 3) 8 (OH) 6 /CdS heterojunctions (NiPO/CdS) are constructed for the first time by loading open framework structure NiPO on the surface of CdS nanoparticles (CdS NPs). The built-in electric field generated at the interface promotes the directional migration of photogenerated electrons from NiPO to CdS. This S-scheme pathway achieves a strong redox capacity and efficient carrier separation. More importantly, the unique triangular and hexagonal channels of NiPO facilitate the exposure of CdS active sites for proton adsorption, H 2 production and escape. The hydrogen evolution rate of NiPO/CdS is 39 mmol g−1 h−1 under visible light irradiation, which is 6.5 times higher than that of pure CdS. The NiPO/CdS heterojunction also exhibits remarkable long-term stability. This study provides a new strategy for the ingenious design of S-scheme photocatalysts with excellent photocatalytic performance. [ABSTRACT FROM AUTHOR]

A graph is called Q-integral if its signless Laplacian spectrum consists of integers. In this paper, we characterize a class of k-cyclic graphs whose second smallest signless Laplacian eigenvalue is less than one. Using this result we determine all the Q-integral unicyclic, bicyclic and tricyclic graphs. [ABSTRACT FROM AUTHOR]

[Display omitted] Multiple surface/interface engineering is an effective approach to develop efficient electrocatalysts for promoting the practical application of electrocatalysis and achieving carbon neutrality. Herein, a deep eutectic liquid precursor containing phosphorus was designed. The self-supported three-dimensional (3D) cobalt-doped Ni 12 P 5 /Ni 3 P nanowire networks coated with a thin layer of carbon (Co-Ni x P@C) were prepared by using an in-situ one-step pyrolysis method. The as-obtained Co-Ni x P@C hybrid possesses a superaerophobic/superhydrophilic surface, which could promote electrolyte diffusion and enhance bubble release. Density functional theory (DFT) calculations reveal that Co-doping in Ni x P@C can promote the adsorption and activation of 5-hydroxymethylfurfural (HMF) molecules, and optimize the energy barrier of H* absorption. The self-supported Co-Ni x P@C was used as an efficient bifunctional electrocatalyst for HMF oxidation coupled with hydrogen evolution reaction (HER) in a 1.0 M KOH solution. A nearly 100 % yield of 2,5-furandicarboxylic acid (FDCA) was achieved. The self-supported Co-Ni x P@C displayed high activity and stability for both HER and HMF conversion. The HMF oxidation coupled with HER can be efficiently driven by a 1.5 V commercial photovoltaic panel under sunlight. This study lays the foundation for large-scale industrialization in sustainable fine-chemical and energy engineering. [ABSTRACT FROM AUTHOR]

[Display omitted] Nanostructured electrocatalysts with unique surfaces and interfaces for hydrogen evolution reaction (HER) are crucial for achieving high performance in universal pH water and natural seawater. Herein, a supramolecular liquid precursor was designed and applied to grow Ni x Co 4-x N/N-doped carbon (NC) ultrathin nanosheet arrays (Ni x Co 4-x N/NC) on carbon cloth through one-step pyrolysis. According to the X-ray absorption spectra, Ni was successfully alloyed into Co 4 N to form Ni x Co 4-x N/NC, which regulates the intrinsic electronic structure and optimizes the adsorption/desorption energy of the catalyst. The unique structure of Ni x Co 4-x N anchored on NC can increase the electron transport efficiency and protect the catalyst from corrosion in the extreme corrosive electrolytes. As a result, the Ni x Co 4-x N/NC catalyst exhibits excellent electrocatalytic HER activity over a wide pH range requiring only 46, 75, and 55 mV at 10 mA/cm2 in the acidic, neutral, and alkaline electrolytes, respectively. Interestingly, the catalyst also shows outstanding HER performance in the natural seawater. This work provides an alternative option for the rational design of efficient electrocatalysts for universal pH water/seawater splitting. [ABSTRACT FROM AUTHOR]

Atomically precise nanoclusters (NCs) provide opportunities for correlating the structure and electrocatalytic properties at atomic level. Herein, we report the single-atom doping effect and ligand effect on CO2 electroreduction (eCO2RR) by comparing monogold-doped Au1Cu24 and homocopper Cu25 NCs protected by triphenylphosphine or/and tris(4-fluorophenyl)phosphine. Catalytic results revealed that the electronic distribution of Cu25 NCs is enormously contracted by doping Au atoms, entitling it to exhibit the unique inhibition of hydrogen evolution reaction. And the inductive effect of ligand strongly favors the formation of formate in eCO2RR. Overall, this work will provide guidance for the rational design of the copper-based catalysts in the eCO2RR. Tuning the metal core and ligand environment of atomically precise nanoclusters enables the correlation of structural and electrocatalytic properties at an atomic level. Here, single-atom doping and ligand tuning of atomically precise copper clusters is shown to be an effective route to tuning CO2 electroreduction activity and selectivity. [ABSTRACT FROM AUTHOR]

The construction of a bifunctional electrocatalyst with excellent performance and low cost plays a key role in the application prospect of renewable energy. Herein, nickel sulfide/CoFe layered double hydroxide heterostructures on nickel foam (NiS/LDH/NF) have been constructed by using hydrothermal and electro-deposition methods. The amorphous nickel sulfide is deposited on the surface of crystalline LDH mesh-like nanosheets to form a hierarchical flower-like structure. The deposition of amorphous NiS can control the morphology and modulate the electronic structure of NiS/LDH/NF. The obtained NiS/LDH/NF is employed as a bifunctional catalyst for overall water splitting, which can achieve a current density of 10 mA cm−2 at a low voltage of 1.51 V in 1 M KOH. The results show that the high electrocatalytic activity is ascribed to the formation of amorphous NiS/crystalline LDH heterostructure with abundant surface defects and active sites. The synthetic strategy holds a great promise for accelerating the development of hydrogen energy by highly efficient electrocatalytic production of hydrogen. [Display omitted] • Flower-like amorphous NiS/crystalline CoFe LDH heterostructure were constructed. • The morphology of catalyst was controlled by electrodeposition of amorphous NiS. • The hierarchical crystalline/amorphous heterostructure provides abundant active sites. • It can achieve 100 mA cm−2 at 206 mV for HER and 273 mV for OER in 1 M KOH. [ABSTRACT FROM AUTHOR]

[Display omitted] Constructing photocatalysts with high activity and anti-photocorrosion is a key to harvesting hydrogen energy from seawater efficiently. Herein, graphene oxide closely coupled high-index facets CdZnS with rich sulfur vacancies (Vs-CZS@GO) has been successfully synthesized via one-pot sulfidation accompanied pyrolysis. DFT calculation confirmed the delicate surface/interface/defect engineering endowed high-index facets Vs-CZS@GO with a lower ΔG H* value and significant charge transfer behavior for efficient H 2 -generation. The synergistic effect of sulfur vacancy, high-index facets, and tightly coupling interface not only enhanced intrinsic active sites and carrier separation efficiencies, but also greatly promoted H 2 evolution rate and stability. Consequently, Vs-CZS@GO displayed a significantly high H 2 -generation rate of 23.2 mmol∙g−1∙h−1 in natural seawater under visible-light irradiation, which is up to 82% of that in pure water. This work provides deeply insight into the synergistic regulation of electronic structure for exposed high-index facets photocatalysts via defect engineering and interface engineering for synergistic boosting visible-light-to-H 2 evolution. [ABSTRACT FROM AUTHOR]

Semimetal Bi and Sb thin films with novel hierarchical structures were synthesized on zinc substrate via a hydrothermal method. X-ray diffraction (XRD) analysis confirmed the formation of pure semimetals Bi and Sb. Scanning electron microscopy images showed that Bi films constructed with microtube arrays and hierarchical microspheres can be obtained selectively by altering the concentration of Bi3+ ions. The synthesized Sb films were constructed with bowl-shaped particles. The growth process of these semimetal architectures was briefly discussed. [ABSTRACT FROM AUTHOR]

• An adaptive switchable coating based on hydrogel was designed. • Thermochromic hydrogel coating can save ∼ 20.3 % of energy consumption. • At T c from 20 °C to 60 °C, net power ranged from 675.0 W·m−2 to − 86.2 W·m−2. • A ∼ 10 °C or 7 °C lower temperature can be achieved compared with reference coatings. In outdoor environments, solar heating in summer leads to the overheating of equipment or buildings while in winter these objects would overcool and would necessitate heating to maintain their suitable operating temperature. Temperature regulation based on cooling and heating accounts for global energy consumption and global greenhouse gas emissions. In this work, a strategy based on a high emittance polymer, thermochromic hydrogel, and black solar absorber was proposed to passively control temperature by regulating solar heating under sunlight. The system can seamlessly transition between "cooling" and "heating" modes based on the critical temperature T c of the thermochromic hydrogel. T c can be adjusted within a range of 25 °C to 45 °C to accommodate diverse temperature control requirements. When the temperature of the coating material stack increased from 20 °C to 60 °C, the heating/cooling power ranged from 675.0 W·m−2 to − 86.2 W·m−2, switching from the "heating" to "cooling" modes, respectively. The designed coating demonstrated a potential energy-saving capability, with approximately 20.3 % reduction in energy consumption compared to conventional coatings. Outdoor experiments revealed that the temperature of the coating remained more stable and was approximately 10 °C or 7 °C lower than that of reference coatings. These results indicated combining solar heating and radiative cooling with thermochromic hydrogels can provide a potential approach to achieving outdoor adaptive temperature control for energy saving. [ABSTRACT FROM AUTHOR]

Abstract: Cuboid-shaped ZnO hierarchical structures constructed with quasi-single-crystalline ZnO nanosheets were fabricated through a mixed surfactants mediated hydrothermal method. The products were characterized by XRD, SEM, TEM, and ED methods. Room temperature photoluminescence spectrum of the as-obtained ZnO hierarchitectures was recorded showing multiple peaks of visible emissions in blue-green region. The synergetic effect of citrate and surfactants SDBS and OP was believed to play a key role in controlling the construction features of ZnO nanosheets. The ZnO hierarchitectures showed effective photocatalytic activity for the decomposition of methyl orange. [Copyright &y& Elsevier]

Abstract: A simple and facile solution route has been developed for phase and morphology controllable synthesis of antimony trioxide (Sb2O3) microcrystals. Orthorhombic phase and cubic phase Sb2O3 microcrystals have been selectively synthesized in high yield. The products were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The as-obtained microcrystals exhibited a variety of morphologies and structures, such as microspindles, nanoplates, and octahedra. Several experimental parameters have been investigated to gain morphology control of Sb2O3 microcrystals. Based on the time-dependent experimental results, an aggregation, and recrystallization mechanism was proposed to describe the formation process of these novel microstructures. [Copyright &y& Elsevier]

Mono-dispersed oxide and hydroxide nanoparticles have been synthesized through the solvothermal process in alcohol-water mixtures. The products were characterized by powder x-ray diffraction (XRD) and scanning electron microscopy (SEM). Plate-like nanoparticles are obtained for Bi2O2.33, Fe2O3, and Cd(OH)2, and spherical nanoparticles are obtained for SnO2. The growth mechanism for the mono-dispersed nanoparticles has been preliminarily discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • rh/c-In 2 O 3 /CdIn 2 S 4 heterostructure was constructed via in-situ pyrolysis of a liquid deep eutectic solvent precursor. • The nano-flakelets stacking structure provide larger surface area and more active sites. • Fermi level and internal electric field promote higher carrier spatial separation. • The unique S-scheme mechanism achieves enhanced visible-light H 2 production. Narrow band gap semiconductors have attracted more attention in photocatalytic. It is still a challenge to design heterojunction photocatalysts with efficient visible-light-harvesting and high redox ability water splitting hydrogen fuel production. Herein, a ternary heterojunction of rhombic phase In 2 O 3 (rh-In 2 O 3)/cubic phases In 2 O 3 (c-In 2 O 3) homojunction combined CdIn 2 S 4 (rh/c-IO/CIS) was designed and constructed via in-situ pyrolysis of a liquid precursor. The as-synthesized rh/c-IO/CIS heterojunction exhibits a nanoplate structure composed of multilayers of tightly coupled ultrathin flakelets. The nanoflakelets stacking structure endows abundant exposed active sites and efficient visible-light-harvesting. Experimental results show rh/c-IO/CIS heterojunction follows a S-scheme mechanism proving high charge separation efficiency and strong redox capability. Thus, the catalyst exhibits excellent photocatalytic hydrogen production performance. The hydrogen evolution rate can get 4.7 mmol·g−1·h−1, it is 3.6 folds and 7.8 folds higher than that of CdIn 2 S 4 and rh/c-In 2 O 3. This work provides a new tack for rational design and fabrication of photocatalysts with enhanced photocatalytic hydrogen energy production performance. [ABSTRACT FROM AUTHOR]

Cooperative vehicle safety systems (CVSSs) rely on vehicular networking for broadcasting state information in order to track neighbors’ positions and, therefore, to predict potential collisions. In vehicular networking, a large number of vehicles compete for access to the limited channel resource, causing channel congestion. The vehicle tracking accuracy, which is the basis for CVSSs, therefore, can be heavily affected. Moreover, the available channel resources must be shared among vehicles in a fair way in order to maintain accurate tracking accuracy for each vehicle. To realize fair access to channel resources while maintaining an accurate tracking performance under conditions of dynamic vehicle density, in this paper, we present a distributed fair transmission rate control strategy, based on multi-agent model predictive control (MPC). We first propose a dynamic information dissemination rate model to capture the state information dissemination ability under conditions of dynamic vehicle density. Then, we present a multi-agent information dissemination model, in which each vehicle is controlled by a control agent that uses MPC and coordinates with its neighboring agents in order to determine its optimal transmission rate actions. We then design an augmented-Lagrangian-based distributed decision-making scheme to find the optimal transmission rate actions and, at the same time, reach an agreement on fair and efficient channel utilization among the vehicles. Simulation results confirm that the distributed transmission rate control strategy can guarantee fair access to channel resources while achieving the optimal vehicle tracking performance under conditions of dynamic vehicle density. [ABSTRACT FROM AUTHOR]

Ni-doped CeO 2 @NiO heterostructures were designed and facilely prepared with NiO nanosheets rooting into Ni-CeO 2 porous microspheres. NiSO 4 was found to be crucial for the self-assembly of Ni-doped CeO 2 porous microspheres. The growth mode of NiO nanosheets rooting into CeO 2 microspheres ensured not only intimate contact between CeO 2 and NiO for facile O 2 and CO mobility but also high structure stability of Ni-doped CeO 2 @NiO microspheres. The as-obtained Ni-doped CeO 2 @NiO heterostructures exhibited enhanced performance for catalytic CO oxidation. Cycling tests showed their good reproducibility and stability. The enhancement should be attributed to synergistic effects between Ni-CeO 2 and NiO as well as the more exposed active sites on NiO nanosheets and Ni-CeO 2 . [ABSTRACT FROM AUTHOR]

The crystal phase and morphology of MoO3 materials were precisely tuned under suitable synthetic conditions and mutual transformation of h-MoO3 and α-MoO3 was achieved via a facile hydrothermal method for the first time. The h-MoO3 microrods with a diameter of 0.5–1.6 μm and length of 2.2–6.1 μm were fabricated with the assistance of NaNO3 using α-MoO3 particles as the precursor. The transformation of h-MoO3 microrods to α-MoO3 nanobelts with a diameter of 150–430 nm and length of 2.1–14.5 μm occurred through hydrothermal techniques at higher temperature. Systematic studies of synthetic parameters revealed that the hexagonal h-MoO3 microrods formed at higher concentration of NaNO3, while h-MoO3 microrods vanished at higher temperature with prolonged time and α-MoO3 nanobelts were exclusively produced. The h-MoO3 microrods exhibited higher catalytic activity in photo-degradation of methylene blue than the α-MoO3 nanobelts. This is ascribed to the weaker fluorescence and reduced bandgap energy of the h-MoO3 microrods than those of the α-MoO3 nanobelts. [ABSTRACT FROM AUTHOR]

Electrochemical nitrogen reduction reaction (NRR) is considered as an alternative to industrial Haber-Bosch N 2 fixation process. Herein, an iodide ion assisted one-step hydrothermal method was developed to prepare Bi 2 MoO 6 nanosheets with oxygen vacancies (OVs) and low-valent bismuth at the surface. The introduction of OVs makes Bi 2 MoO 6 nanosheets possess rich unsaturated coordination surface atoms, and enhances the conductivity and N 2 adsorption. Low-valent bismuth with 6p orbits reinforces the interaction with N 2 via π back-donation. The high-efficiency adsorption and protonation of N 2 over OVs-Bi 2 MoO 6 catalyst was confirmed by N 2 in-situ DRFTIR spectra and temperature-programmed-desorption. The obtained OVs-Bi 2 MoO 6 nanosheets accomplished a favorable ammonia yield of ∼24.38 μg·mg−1 h −1 and a high Faradaic efficiency of 14.1% at −0.3 V in 0.1 M HCl solution. A feasible OVs assisted π back-donation mechanism was proposed for the enhanced NRR catalytic activity on OVs-Bi 2 MoO 6 catalyst. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Co 4 N/NC@CC self-supported electrode was prepared by one-step pyrolysis solution process. • Deep eutectic solvent ensures Co 4 N to in situ couple tightly with NC. • Co 4 N/NC@CC are efficient for biomass conversion and hydrogen fuel production synchronously. • This work contributes to the green production and efficient conversion of renewable energy in industry. Metal nitrides are considered promising catalysts for the hydrogen evolution reaction integrated with electrooxidation reaction of biomass due to their metal-like properties. However, the synthesis of metal nitrides involves multi-step reactions and requires continuous reactions under a large amount of NH 3 atmosphere. Herein, we exploit deep eutectic solvent (DES) to induce in-situ synthesize N -doped carbon (NC) composite Co 4 N ultrathin nanosheets self-supporting electrode on carbon cloth (Co 4 N/NC@CC) without additional input NH 3 atmosphere. XAFS spectra showed that the strong interaction between Co 4 N and NC accelerated the electron transport at the interface, and the ultrathin nanostructure of Co 4 N/NC is beneficial to increasing the catalytic active sites, thereby effectively improving the catalytic performance of Co 4 N/NC@CC. During the HER process, Co 4 N/NC@CC only needs 62, 98, and 60 mV overpotentials to reach a current density of 10 mA/cm2 in alkaline, neutral, and acidic electrolytes. When Co 4 N/NC@CC is used to produce 2,5-furandicarboxylic acid (FDCA) and hydrogen fuel synchronously in alkaline electrolytes, only a low voltage of 1.38 V is required at 10 mA/cm2, and the conversion rate of 5-hydroxymethylfurfural (HMF) is close to 100 % and the selectivity of FDCA is 98.6 %. [ABSTRACT FROM AUTHOR]

Metal chalcogenides still suffer from the fast recombination of photoinduced charges and serious photo-corrosion when used as visible-light-responsive photocatalysts. The rationally designed photocatalysts should simultaneously possess high light-harvesting efficiency, fast charge separation, optimum redox ability and lasting stability, and this remains a big challenge. Herein, 0D WO 3 nanoparticles (NPs) were prepared by using a deep eutectic solvents (DESs) pyrolysis method. And then 0D WO 3 NPs coupled 1D Mn 0.1 Cd 0.9 S (MCS) nanorods were introduced to construct the S-scheme 1D/0D MCS/W heterojunction cauliflower-shaped assemblies, which were developed by using a simple hydrothermal method. X-ray photoelectron spectra disclosed the formation of the S-W-O bond, indicating strong interfacial interaction between MCS and WO 3 at the heterojunction. The formed S-scheme 1D/0D MCS/W heterojunction cauliflower-shaped assemblies and the construction of internal electric field not only enhance visible light absorption, but also boost charge separation efficiency, and endow higher redox ability and long-term durability. Profiting from morphological and energy band structure synergy, the resultant MCS/W heterojunction assemblies exhibited an enhanced photocatalytic H 2 generation rate of 21.25 mmol h−1 g−1, which was 25 times higher than that of pristine MCS. This work provides new deep insights into the rational construction of S-scheme heterojunction assemblies based on morphology and band structure design to boost the photocatalytic performance. [Display omitted] • S-schemed 1D/0D Mn 0.1 Cd 0.9 S/WO 3 hierarchical heterojunction assemblies were constructed. • The interconnected flower-like skeletons effectively promote charge and mass migration. • The heterojunction displayed a stronger light-harvesting ability and optimum redox ability. • Highly improved separation efficiency of photogenerated electrons and holes. • Visible-light driven photocatalytic H 2 evolution increased by 25.0 time. [ABSTRACT FROM AUTHOR]

The rational design and development of highly efficient non-precious metal chalcogenide electro-catalysts is key but challenging technology for biomass conversion into high-valued chemicals coupling hydrogen evolution. Herein, the NiS quantum dots (QDs) with good dispersibility embedding into wrinkled N,O,S-tri-doped carbon porous nanosheets (NiS@NOSC) implanted in-situ on carbon cloth were synthesized via a facile one-step pyrolysis method. The as-obtained NiS@NOSC porous nanosheets network displays excellent superhydrophilic/superaerophobic surface, facilitating fast diffusion of ion and release of H 2 bubble. The self-supported NiS@NOSC on carbon cloth could serve as both cathode and anode electrodes for high-efficient electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) into high-valued 2,5-furandicarboxylic acid (FDCA) coupling hydrogen evolution requiring only a low potential of 1.51 V to afford 50 mA cm−2. The high electrocatalysis performance is attributed to the synergistic effect of high activity of monodisperse NiS QDs, superhydrophilic/superaerophobic network structure, and the electronic regulation between NOSC and NiS QDs in NiS@NOSC, which has promising foreground to fulfil large-scale commercialize application. [Display omitted] • NiS QDs embedded in N,O,S-tri-doped ultra-thin carbon network were fabricated. • NiS@NOSC exhibited admirable catalytic ability for both HER and HMF oxidation. • The superhydrophilic/superaerophobic nature enable the catalyst with superior performance. • The two-electrode device based on NiS@NOSC || NiS@NOSC only needs 1.51 V to offer 50 mA cm−2. [ABSTRACT FROM AUTHOR]

Pompon-like Ni-doped α-FeOOH nanostructures were prepared through a simple low temperature solution aging process. After calcination, Ni-doped α-Fe 2 O 3 could be obtained with their original morphology being maintained. Experimental results indicated that NiSO 4 in the reaction plays dual functions of doping and morphology controlling. The magnetic properties and the adsorption performance of the products were evaluated. The Ni-doped α-Fe 2 O 3 nanostructures showed high adsorption performance to remove Congo red (CR) dye from water. [ABSTRACT FROM AUTHOR]

[Display omitted] • New thermodynamically favorable HER route can be realized on protonated g-C 3 N 4. • S-scheme protonated g-C 3 N 4 QDs/V O -ZnO hybrid was prepared as efficient photocatalyst. • S-scheme fabrication promotes V O generation in ZnO and protonation of g-C 3 N 4 QDs. • V O at hybrid interface significantly facilitates S-scheme electron transfer. • Protonated edge N atom was the main active sites in low energy barrier HER process. Traditional photocatalytic hydrogen evolution path with high energy barrier of proton adsorption limits the reaction efficiency. Specific regulation on active site to realize low energy barrier hydrogen generation provides a new perspective. In this work, an innovative low barrier route is provided on protonated N of g-C 3 N 4 of S-scheme protonated g-C 3 N 4 quantum dots/ZnO hybrid rich in oxygen vacancies (p-CNQDs/V O -ZnO). V O generated by quantum dots doping optimizes the electron structure of S-scheme, whereas the intensive electron directional transmission in S-scheme promotes protonation of p-CNQDs. Profited from the synergies of thermodynamic and dynamic, protons and electrons concentrate at edge-active N accomplish the efficient photocatalytic HER with a 117-fold elevated H 2 evolution. This work provides more possibilities for designing low energy pathway and efficient catalyst in H 2 evolution reaction. [ABSTRACT FROM AUTHOR]

• One-step synthesis of N-doped carbon quantum dots hybridized NiFe-LDH of 1.4 nm thickness. • The BET surface area of the products was 226.7 m2 g−1. • The overpotential is 363 mV at large current density of 500 mA cm−2. • NCD@NiFe-LDH shows excellent durability and stability at 1000 mA cm−2. Herein, we have developed a one-step ionothermal accompanied thermolysis strategy based on metal chloride deep eutectic solvent (DES) precursors to synthesize NiFe layered double-hydroxide ultrathin nanosheets hybridized with N-doped carbon quantum dots (NCD@NiFe-LDH). The NCD@NiFe-LDH hybrid shows hierarchical three-dimensional flower-like morphology assembled with ~1.4 nm ultrathin nanosheets possessing higher surface area values and well conductivity. The as-synthesized NCD@NiFe-LDH hybrid exhibits excellent performance for oxygen evolution reaction (OER) and just require 363 mV to achieve a higher current density of 500 mA cm−2 compared to the state-of-the-art IrO 2 in 0.1M KOH. Besides, NCD@NiFe-LDH hybrid shows long-term stability and satisfactory durability even at 1000 mA cm−2. Such an excellent OER performance at high current density can be ascribed to the unique porous ultrathin structure with abundant active edges and sites and the synergistic effect of the NCD and NiFe-LDH. The work offers a new way for the design and synthesis of other carbon-hybridized LDH ultrathin nanosheets with unique electrochemical properties. [ABSTRACT FROM AUTHOR]

Abstract: CdS hollow spherical particles with different sizes have been prepared using core/shell fabrication method with poly-(styrene–acrylic acid) (PSA) latex particles as template. The sodium salt of extractant P204 (di-(2-ethylhexyl) phosphoric acid) was used firstly as the emulsifier in the template synthesis. The diameters of the polymer core decreased from 300 to 120nm on average with increasing of the amount of emulsifier from 1.56 to 3.54%. As a result the diameters of the hollow spheres ranged from 350 to 150nm. The products were characterized by TEM, IR and XRD, respectively. [Copyright &y& Elsevier]

CdS nanowires with typical length more than 8μm and width of 30nm on average have been successfully synthesized through Cd(NO3)2 reacting with CS2 and ethylenediamine in microemulsion system of sodium dodecylbenzene sulfonate (SBDS). The microstructures of the as-synthesized CdS nanowires were characterized using XRD, transmission electron microscopy (TEM) and HRTEM. The possible formation mechanism was discussed. The morphologies of CdS sample strongly depend on the concentration of surfactant in solutions. [Copyright &y& Elsevier]

• Cu 2 O nanospecies anchored on/within mesoporous TiO 2 forming hybrid photocatalyst. • Oxygen vacancy stimulated Z-scheme mechanism inhibits photo corrosion of Cu 2 O. • High activity and stability for hydrogen production in both water and seawater. • Strong coupling between Cu 2 O and TiO 2 extends visible light absorption and charge separation. [Display omitted] Oxygen vacancy stimulated direct Z-scheme Cu 2 O/TiO 2 hybrid photocatalysts were designed and constructed through a Cu2+ ions adsorption-reduction strategy with Cu 2 O nanospecies decorated on/within mesoporous TiO 2 microspheres. Narrow band gap of Cu 2 O favors visible light absorption. The mesoporous structure stabilizes Cu 2 O nanospecies and benefits the efficient charge carrier mobility and light harvest. The high specific surface area provides more photocatalytic active sites for both Cu 2 O and TiO 2 components. Oxygen vacancy stimulated all-solid direct Z-scheme electron transport mechanism was proposed to explain the high activity and stability of the hybrid catalyst. The catalyst behaves enhanced hydrogen evolution rate of 11 mmol h−1 g−1 in water and 5.1 mmol h−1 g−1 in seawater, respectively. The highest AQY of hydrogen production is 15.1% in water (and 8.4% in seawater) at 365 nm. The work will provide new insight for controllable creation of Z-scheme photocatalysts for practical hydrogen evolution from water and seawater splitting. [ABSTRACT FROM AUTHOR]

Fe 3 O 4 /Fe 2 O 3 composite hollow spheres were successfully synthesized by simply aging Fe 3 O 4 nanospheres in a FeCl 3 solution. A possible formation mechanism for the formation of the composite hollow spheres was suggested involving a coating combined with Kirkendall effect process. The Fe 3 O 4 /Fe 2 O 3 composites possess ferromagnetic properties and excellent magnetic responsivity and redispersibility. The charge/discharge results indicated that the composites exhibit enhanced Li ion battery performance comparing with Fe 3 O 4 nanospheres. [ABSTRACT FROM AUTHOR]