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In this paper, the synthesis of ZnO tetrapods and its application as electrode materials for high-performance supercapacitors have been reported. The galvanostatic charge-discharge measurement results show that the specific capacitances of the ZnO tetrapods-based electrodes increase with the decrease of the current densities. The maximum capacitance is 160.4 F g –1 at the current density of 1.0 A g –1 . The Ragone plot shows that the ZnO tetrapods have excellent supercapacitive performance. Moreover, the cyclic stability is measured by the galvanostatic charge/discharge technique at a constant current density of 10.0 A g –1 in 1.0 M Na 2 SO 4 aqueous electrolyte. The results show the excellent capacitance retention of 94.3% over 1000 cycles. In a word, ZnO tetrapods should be the ideal potential electrode materials for low-costing and effective electrochemical supercapacitors. [ABSTRACT FROM AUTHOR]

In this paper, the surfaces of ZnO tetrapods were modified by Na 2 S to form composite ZnS/ZnO hollow tetrapods for the first time. Two-photon luminescence spectra with the excitation having double longer wavelength than the emission indicated that two-photon absorption was involved in the excitation processes, and the photon luminescence enhancement of ZnS/ZnO hollow tetrapods more than that of ZnO tetrapods was ascribed to the capping of ZnS, which could passivate the surface traps of ZnO. The time-resolved PL decay traces showed that the lifetime of ZnO/ZnS hollow tetrapods was much longer than that of ZnO tetrapods due to the capping of ZnS on the surface of ZnO causing the reducing surface defects and then significant effect on its surface states. [ABSTRACT FROM AUTHOR]

One dimensional (1D) nano-structured arrays have attracted great interests in recent years. In this paper, Cu(OH) 2 and ZnO nanoarrays on corresponding metal substrates have been successfully prepared by a gas-solution-solid method. The nanoribbons arrays of Cu(OH) 2 were about 10 μm in length on average and the widths vary from 0.6 to 3.2 μm depending on different treatment conditions. Similarly, the diameters of ZnO nanorods could be controlled from 20 to 200 nm by adjusting ammonia concentrations. The growth mechanisms for Cu(OH) 2 and ZnO nanoarrays were studied and proposed. Briefly, Cu(OH) 2 and ZnO nanoarrays were grown from the tips with the help of ammonium in the solution as transporters of copper and zinc ions. Moreover, the NH 3 sensing properties were measured and the results showed that both nanoarray sensors have high sensitivity and reversibility for NH 3 probing at room temperature. [ABSTRACT FROM AUTHOR]

In this work, highly dispersed Au nanoparticles (NPs) decorated SiC nanowires (NWs) hybrids were firstly synthesized by a facile deposition-precipitation method. The as-prepared Au/SiC samples were characterized using various instrumental methods such as XRD, TEM, EDS, UV–vis DRS, BET, FTIR, XPS, PL, TRPL, and photoelectronchemical measurements. The solar H 2 production performances were investigated by using Na 2 S as sacrificial reagents in water under simulated sunlight illumination produced from a 300 W xenon lamp. Results showed that a significantly enhanced photoactivity for H 2 evolution (1495.8 μmol h −1 ·g −1 ) with apparent quantum efficiency (AQE) of 2.12% was achieved over the compostion-optimized Au/SiC composite (with 0.5 wt% Au), which was much higher than those of pure SiC NWs, Pt NPs deposited SiC NWs sample as well as the previously reported SiC-based catalysts. In cyclic tests, the AS0.5 showed acceptable photocatalytic stability and good structural stability. PL, TRPL and photoelectrochemical measurements disclosed that improved charge separation and retarded charge recombination were realized. However, the Au-loaded SiC products with strong surface plasmon resonance (SPR) absorption showed no activity for visible light photocatalytic H 2 production (λ ≥ 400 nm). Based on band-gap structures, the critical factors for SPR effect of Au NPs in activating or enhancing the visible-light photoactivities of semiconductors were proposed. This work can pave the avenue to the development of plasmonic metal decorated other narrow band gap semiconductors with plasmon-enhanced visible-light photoactivity for solar water splitting and related applications. [ABSTRACT FROM AUTHOR]

In this research, CePO 4 microbundles composed of aligned nanorods have been successfully synthesized through a facile surfactant-free hydrothermal route. The whole synthetic process was rather simple and green. And different synthetic parameters including the aging time and acidic strength were investigated such to understand the formation of the novel hierarchical microarchitectures. It was found that the hydrothermal time, as well as the acidic strength of the precursor media played a key role in mediating the assembly of one-dimensional micrcobundles from initially formed nanorods. Based on a series of experimental observations, a ‘precipitation-growth’ mechanism is proposed to describe the growth of the unique microstructures. [ABSTRACT FROM AUTHOR]

Recently, China has frequently experienced large-scale, severe and persistent haze pollution due to surging urbanization and industrialization and a rapid growth in the number of motor vehicles and energy consumption. The vehicle emission due to the consumption of a large number of fossil fuels is no doubt a critical factor of the haze pollution. This work is focused on the causation mechanism of haze pollution related to the vehicle emission for Guangzhou city by employing the Fault Tree Analysis (FTA) method for the first time. With the establishment of the fault tree system of “Haze weather—Vehicle exhausts explosive emission”, all of the important risk factors are discussed and identified by using this deductive FTA method. The qualitative and quantitative assessments of the fault tree system are carried out based on the structure, probability and critical importance degree analysis of the risk factors. The study may provide a new simple and effective tool/strategy for the causation mechanism analysis and risk management of haze pollution in China. [ABSTRACT FROM AUTHOR]

In this paper, an effective strategy using potassium dichromate lotion to activate surfaces of commercial carbon papers leading to enhanced electrochemical capacitances was reported. It is revealed that surfaces of activated carbon papers became rougher and their specific surface areas enlarged after treatment. Further, surface hydrophilicity of the treated carbon papers enhanced due to the generation of hydrophilic groups such as hydroxyl (–OH), carbonyl (〉C O) and carboxyl (–COOH) and they act as strong polar sites to absorb water molecules. With the synergistic effect of enlarged specific surface area and enhanced surface hydrophilicity, the activated carbon papers provide high areal capacitances. In general, this strategy offers a feasible pathway to make commercial carbon paper a promising candidate for practical supercapacitors and is expected to extend to other carbon based electrode materials. [ABSTRACT FROM AUTHOR]