Search

Summary: Plasmon-assisted chemical transformation holds great potential for solar energy conversion. However, simultaneous enhancement of reactivity and selectivity is still challenging and the mechanism remains mysterious. Herein, we elucidate the localized surface plasmon resonance (LSPR)-induced principles underlying the enhanced activity (∼70%) and selectivity of photoelectrocatalytic redox of nitrobenzene (NB) on Au nanoparticles. Hot carriers selectively accelerate the conversion rate from NB to phenylhydroxylamine (PHA) by ∼14% but suppress the transformation rate from PHA to nitrosobenzene (NSB) by ∼13%. By adding an electron accepter, the as-observed suppression ratio is substantially enlarged up to 43%. Our experiments, supported by in situ surface-enhanced Raman spectroscopy and density functional theory simulations, reveal such particular hot-carrier-induced selectivity is conjointly contributed by the accelerated hot electron transfer and the corresponding residual hot holes. This work will help expand the applications of renewable sunlight in the directional production of value-added chemicals under mild conditions.

Abstract The oxygen reduction reaction (ORR) is the core reaction of numerous sustainable energy‐conversion technologies such as fuel cells and metal–air batteries. It is crucial to develop a cost‐effective, highly active, and durable electrocatalysts for ORR to overcome the sluggish kinetics of four electrons pathway. In recent years, the carbon‐based electrocatalysts derived from metal–organic frameworks (MOFs) have attracted tremendous attention and have been shown to exhibit superior catalytic activity and excellent intrinsic properties such as large surface area, large pore volume, uniform pore distribution, and tunable chemical structure. Here in this review, the development of MOF‐derived heteroatom‐doped carbon‐based electrocatalysts, including non‐metal (such as N, S, B, and P) and metal (such as Fe and Co) doped carbon materials, is summarized. It furthermore, it is demonstrated that the enhancement of ORR performance is associated with favorably well‐designed porous structure, large surface area, and high‐tensity active sites. Finally, the future perspectives of carbon‐based electrocatalysts for ORR are provided with an emphasis on the development of a clear mechanism of MOF‐derived non‐metal‐doped electrocatalysts and certain metal‐doped electrocatalysts.

An electrochemical method is presented by which nickel (Ni) hollow nanoscale structures can be prepared. The electrochemical deposition was carried out on copper (Cu) substrates under galvanic conditions.

A study of a novel paddle-wheel-like octanuclear Cu(II) complex, namely, [Cu8(dpd-2H)(sub 4)(mu(sub 2)-O2CMe)(sub 4){2-(OH)C5H4N}(sub 4)]-(ClO4)(sub 4).4H2O (1) [2-(OH)C5H4N = 2-hydroxypyridine], which contains the dianionic ligand dpd-2H is presented. The results show that octanuclear [Cu8(dpd-2H)(sub 4)(mu(sub 2)-O2CMe)(sub 4){2-(OH)C5H4N}(sub 4)](super 4+) cationic core contains two types of copper centers.

The preparation of Bi(sub x)Fe(sub 1-x) intermetallic compounds with nanowire array structure via the nanometer-scale template-based synthesis in conjunction with the electrochemical deposition in an organic bath is described. The magnetic measurement of Bi(sub 1-x) Fe(sub x) intermetallic compound nanowire arrays have showed a spin-glass-like behavior and an unusually large characteristic time, which is about 5.26 h, was obtained at room temperature.

A correction is presented to the article the Electrochemical Society ("ECS"), and published on behalf of ECS by IOP Publishing Limited.

Novel PtCu alloy yolk-shell cubes were fabricated via the disproportionation and displacement reactions in Cu2O yolk-shell cubes, and they exhibit significantly improved catalytic activity and durability for methanol electrooxidation. [ABSTRACT FROM AUTHOR]

Novel hierarchical NiCo 2O4 nanosheets@hollow microrod arrays (NSs@HMRAs) are fabricated by a simple and environmental friendly template-assisted electrodeposition followed by thermal annealing. Due to their unique nanostructures, the NiCo 2O4 NSs@HMRAs, as electrodes, exhibited a high specific capacitance (Csp) (678 F g-1 at 6 A g-1) and outstanding cycle stability (Csp retention of 96.06% after 1500 cycles). The desirable superior capacitive performance of the NiCo 2O4 NSs@HMRAs can be attributed to the large specific surface area, fast ion diffusion, and perfect charge transmission in the hierarchical NSs@HMRAs. The asymmetric supercapacitor (ASC) based on the NiCo2O4 NSs@HMRAs as a positive electrode and active carbon (AC) as a negative electrode was assembled and it exhibited a Csp of 70.04 F g-1 at 5 mV s-1 and a high energy density of 15.42 W h kg-1. Moreover, the NiCO[sub 2]O[sub 4] NSs@HMRAs//AC ASC has an outstanding cycle stability (almost no Csp loss after 2500 cycles), making it promising as one of the most attractive candidates for electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Here the large-area hierarchical Bismuth Molybdate nanowires have been successfully prepared via a facile electrodeposition-heat-method. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and laser micro-Raman spectrometer measurements were employed to characterize the hierarchical Bismuth Molybdate nanowires. In addition, the as-synthesized hierarchical Bismuth Molybdate nanowires manifest a high specific capacity and good electrochemical stability. [ABSTRACT FROM AUTHOR]

Magnetic dendrites of CoPb were fabricated through potentiostatic electrochemical deposition on Cu substrates in boric acid solution at room temperature. The as-deposited dendrites were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), electrodeposition (ED), and energy dispersive X-ray spectroscopy (EDS). SEM results indicate that the CoPb dendrites are highly symmetrical in structures. The diameters of the branches are about 50 ~ 200 nm, and the backbones are continuous with lengths up to about 10 μm. XRD patterns show that the as-deposited dendrites are solid solutions. The annealing treatment can result in the recrystallization of these metastable alloys into two separate phases. TEM, ED, and EDS results also reveal that the backbones and the branches of the dendrites are composed of different amounts of cobalt. Magnetic measurements confirm that the as-deposited CoPb dendrites have a softly ferromagnetic behavior, and a small coercive force (about 80 Oe). Also the saturation magnetizations of the CoPb dendrites decrease rapidly with the temperature increasing. [ABSTRACT FROM AUTHOR]

Single-crystalline CeO2 octahedra were successfully grown on Cu substrates via a facile electrochemical approach, and free-standing CeO2 nanotubes with high crystallinity were also obtained by adjusting the reaction temperature. A ferromagnetic behavior at 5 K arising from their intrinsic defects is observed for the CeO2 octahedra and nanotubes. Furthermore, the CeO2 octahedra and nanotubes exhibit a good photocatalytic performance in the degradation of an organic pollutant in waste water. [ABSTRACT FROM AUTHOR]

ZnO twin nanorods (TNs) have been successfully grown on F-doped SnO2 (FTO) glass by a simple electrochemical assemble process. The TNs were made up of two short nanorods via sharing the same crystallographic orientation along the (001) direction. The optical properties were investigated by UV-vis-NIR spectroscopy and photoluminescence (PL) spectrum. The resulting films had a strong UV absorption from 400 to 350 nm and the intensity of the green emission could be adjusted by changing the current density which might lead the ZnO TNs applicable as photosensitive materials. Moreover, the growth mechanism was studied and the probable electrochemical deposition formation process was proposed. [ABSTRACT FROM AUTHOR]

We report a facile, general and scalable approach towards porous La(OH)3/Pr(OH)3/Nd(OH)3nanowires based on a gas bubble template electrochemical assembly process, and they exhibit a high adaptability for removing Congo red from water. [ABSTRACT FROM AUTHOR]

Core/shell nanostructures often exhibit novel physical and chemical properties. Herein ZnO@MoO3core/shell nanocables have been synthesized in large quantities by a simple electrochemical method at room temperature and the shell thickness of MoO3can be controlled by changing the deposition time. The synthesized core/shell nanocables were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The inner ZnO nanorod shows a single-crystal structure and has preferential growth in the [0001] direction. The MoO3shell also shows a single-crystal structure with a [0001] direction. The prepared ZnO@MoO3core/shell nanocables have been successfully employed as supercapacitor electrodes and give a specific capacitance of 236 F g−1at scan rate of 5 mV s−1, which is much larger than that of MoO3nanoparticles. In addition, ZnO@ MoO3core/shell nanocables show high electrochemical stability and can withstand over 1000 cycles with no obvious decrease in the specific capacitance. [ABSTRACT FROM AUTHOR]

Perfect polycrystalline NiPb dendrites were prepared via cathodic electrochemical deposition on Cu substrates from aqueous solution. Cyclic voltammetry was used to gain insight into the Ni/Pb codeposition mechanism. The results reveal that the dendrite consists of a long central backbone and very orderly secondary and tertiary branches. The size and shape of the dendritic structures can be tunable by changing the synthetic parameters. A formation mechanism is proposed to illustrate the growth process. [ABSTRACT FROM AUTHOR]

Ferromagnetic-nonmagnetic heterogeneous alloy nanostructurcs are attracting growing interest because of their special physical properties, such as giant magnetoresistance effect and mixed magnetism produced by the change in structure, magnetism, or electrical transport. Here, we report a synthesis route for the preparation of CoO/ZnO alloy dendritelike structures consisting of orderly organized hexagonal nanoplatelets by electrochemical deposition in a solution of 1.0 mol/L Zn( NO3)2 + 0.1 mol/L Co(NO3)2 + 3.00 mol/L NH4F + 0.1 mol/L citric acid at 90°C. The main trunk and side branches of the CoO/ZnO alloy dendritelike structure are regularly angled, and each branch is made of periodic hexagonal nanoplatelets. The effects of electrodeposition parameters on the compositions of CoO/ZnO alloy dendritelike structures were studied. The morphologies of CoO/ZnO alloy dendritelike structures can be well controlled by changing deposition current densities or the concentration of Zn(NO3)2. The formation process of the dendritelike arrangement of periodic CoO/ZnO alloy hexagonal nanoplatelets was investigated in this paper. A magnetization measurement indicates that these prepared CoO/ZnO alloy dendritelike Structures have a soft ferromagnetic behavior at 120 Kand a Vortex magnetization at 215 K. [ABSTRACT FROM AUTHOR]

We report here a facile and efficient synthesis route for the preparation of symmetrical PbTe dendritic structures consisted of orderly and regular particles via electrochemical deposition without any templates. The electrochemical reactions relevant to the growth of PbTe intermetallic compounds were studied by cyclic voltammetry, and the formation mechanism of PbTe dendritic structures was investigated. The electrode potential oscillation was relevant to the formation of the PbTe dendrites. The sizes of the particles in dendritic structures were tunable from 100 to 500 nm and the shapes could be controlled to be either starlike or trigonal. These prepared PbTe dendrites were characterized by SEM, EDS, XRD, HRTEM, and SAED, respectively. The DSC analyses were conducted to study the thermal properties of the prepared PbTe dendritic structures. The high transmittance of the PbTe dendritic structures between 500 and 4000 nm were observed, and the band gap energy of the prepared PbTe was calculated about 0.272 eV. [ABSTRACT FROM AUTHOR]