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A MOF material has been grown on metallic transition metal nitride for electrocatalytic OER. The as-prepared hierarchical NiFe-MOF@Ni3N nano/microsheet array electrocatalyst exhibits a low overpotential of 281 mV at a current density of 200 mA cm−2 with a remarkable stability of 50 h. [ABSTRACT FROM AUTHOR]

Self-supported nickel–iron nitride microsheet arrays coated with carbon are grown on commercial Ni foam (NixFeyN@C/NF) and used as an electrocatalyst for splitting of alkaline seawater. The porous architecture and superhydrophilic/superaerophobic surface ensure sufficient exposure of active sites and mass transfer. The synergetic coupling effect between the carbon coating and NixFeyN facilitates electron transport. The optimal anode (Ni3FeN@C/NF) and cathode (Ni3N@C/NF) electrocatalysts are employed to assemble a two-electrode seawater electrolyzer for overall alkaline seawater electrolysis, which delivers a large current density of 500 mA cm−2 at a low cell voltage of 1.91 V. The superior corrosion-resistance and electron conductivity of the electrocatalyst are responsible for its excellent durability up to 100 hours. This result suggests that transition-metal nitrides coated with carbon offer an effective route to fabricate high-performance and durable hybrid electrocatalysts for hydrogen production from seawater electrolysis. [ABSTRACT FROM AUTHOR]

Low-cost, efficient and stable electrocatalysts are required for large-scale production of hydrogen by industrial scale water electrolysis. We report here a hybrid bifunctional electrocatalyst, composed of amorphous NiFe LDH nanosheets and metallic Ni3N microsheet arrays grown on Ni foam for water splitting in alkaline electrolyte. This electrocatalyst possesses a typical 3D hierarchical heterostructure architecture and affords abundant exposed active sites. The strong coupling and synergistic effects between the NiFe LDH nanosheets and the Ni3N microsheet arrays provide a robust integrated structure and fast electron transfer. The superhydrophilic/superaerophobic properties of the electrocatalyst promote the mass transfer particularly at a large current density. By employing the NiFe LDH@Ni3N/NF as a bifunctional electrocatalyst for overall water splitting, an alkaline aqueous electrolyzer exhibits a low cell voltage of 1.80 V at a current density of 500 mA cm−2 with a remarkable durability of 100 h. The bifunctional NiFe LDH@Ni3N/NF electrocatalyst is a very promising candidate for scale-up industrial implementation of hydrogen production due to its excellent catalysis activity and high stability. [ABSTRACT FROM AUTHOR]

It is highly desirable to develop new semiconductors for the photocatalytic reduction of CO2 to CH4 and CO to solve greenhouse effect and energy issues. Defect pyrochlore oxides have a flexible composition and the electron/hole mobility can be manipulated by introducing foreign cations into the structure. Through Sn doping into the defect pyrochlore oxide KNbWO6·H2O, we successfully obtained a 2-times higher photocatalytic activity for converting CO2 to CO, CH4 and O2 compared to the original KNbWO6·H2O. According to the data from UV-vis, photoluminescence, and hydroxyl radical amount-related fluorescence spectra, and CO2 adsorption, the improved photocatalytic activity can be attributed to the extended visible light response, the enhanced charge separation and the improved CO2 adsorption due to Sn doping. Our results provide a new strategy for developing high-performance photocatalysts. [ABSTRACT FROM AUTHOR]

In this work, a novel environmentally friendly approach to deposit TiO2 films via an aqueous process is developed. The atomic force microscopy (AFM) measurement indicates that water-dispersed TiO2 nanocrystals (NCs) show excellent film-forming properties on an ITO-coated glass substrate. In addition, the femtosecond transient absorption (TA) and conductivity measurements suggest that the aqueous-processed TiO2 film shows excellent electron extraction ability and good conductivity. The aqueous-processed polymer/NC hybrid solar cells based on the aqueous-processed TiO2 electron extraction layer present superior photovoltaic performance and a PCE of 5.53% is achieved, which is the highest for hybrid solar cells fabricated via an aqueous process. Finally, the solar cells with the aqueous-processed TiO2 electron extraction layer exhibit better humidity resistance compared to the TiO2 film deposited via a sol–gel method. [ABSTRACT FROM AUTHOR]

Carbon modified lithium titanate (Li4Ti5O12) anode nanocrystals for Li-ion batteries were synthesized by directly treating the titanium alkoxide and lithium acetate ethanol solution via the Reaction under Autogenic Pressure at Elevated Temperature (abbreviated to RAPET). The mixture of the liquid precursors decomposed during the RAPET process and then reacted in situ and transformed into carbon-modified Li4Ti5O12 anode nanocrystals. The organic moieties in the titanium alkoxide and the lithium salt provided both the oxygen and carbon for the synthesis. The resulting products were characterized by X-ray diffraction (XRD), elemental analysis, scanning electronic microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), nitrogen adsorption–desorption measurements, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge testing. The influences of the titanium alkoxide precursors, i.e. the length of the alkoxy group, on the properties of the final products and the presence of the in situ resulting carbon on the electrochemical performance have been investigated. [ABSTRACT FROM AUTHOR]

Semiconductor gas sensors play important roles in detecting toxic gases in various workplaces for human safety. The gas-sensing characteristics of highly orientational CdS dendrite (HOCSD) sensors were investigated. The results showed that the HOCSD sensors exhibited an excellent response and high response speed to HCOOH and N2H4, compared to HCHO and n-BuNH2. The high performance of the HOCSD sensors towards HCOOH and N2H4 detection could be attributed to two factors: the improved diffusion and adsorption/desorption ability of the CdS dendrites, and the synergistic effect of the reduction ability and hydrogen bonds of detected gases. Moreover, it is believed that the HOCSD sensors could be potentially applied to detect the HCOOH and N2H4 with high response, fast response speed and good repeatability. [ABSTRACT FROM AUTHOR]

The inner structure of W18O49 mesocrystals was observed by electron microscopy with the help of ultramicrotomy and focused ion beam techniques. The results showed that these mesocrystals contain irregular mesopores formed through partial fusion of self-assembled nanowires, and consequently have long-range structural ordering in one dimension and short-range ordering in the other two dimensions. The W18O49 mesocrystals exhibit superior performance in gas sensing applications, which is considered to be associated with the presence of more oxygen vacancy sites in the unique mesoporous structure. [ABSTRACT FROM AUTHOR]

Air-stable metallic Co nanoparticles were incorporated into the pores or anchored onto the external surface of an ordered mesporous carbon/SBA-15 composite by simply treating the cobalt precursor-impregnated surfactant-containing SBA-15 via the Reaction under Autogenic Pressure at Elevated Temperature (abbreviated to RAPET) process, resulting in bifunctional Co@carbon/SBA-15 composites. Surfactant-containing mesoporous SBA-15 (denoted as surf-SBA-15 composite) was firstly impregnated with a cobalt precursor solution and then calcined under autogenic pressure at elevated temperature using a Swagelok-like high-temperature autoclave in an N2 atmosphere. During the RAPET process, the cobalt precursor impregnated into the channel of the surf-SBA-15 composites decomposed and was reduced by the surfactant species, meanwhile, the surfactant, which was used as a soft template for the formation of mesoporous silica, was carbonized and coated onto the internal and the external surface of mesoporous silica and partially onto the incorporated metallic Co nanoparticles, forming Co nanoparticles encapsulated by a mesoporous carbon/SBA-15 composite (mesoporous Co@carbon/SBA-15) in situ. The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption measurements and X-ray diffraction (XRD). The influences of the concentration of cobalt precursors on the morphologies and the magnetic properties of the mesoporous Co@carbon/silica composites were studied. The adsorption/separation ability of the magnetic mesoporous composite to organic guest molecules and the stability of the nanosized metallic Co decorations in air or in an acid environment were also investigated. [ABSTRACT FROM AUTHOR]

Hexagonal mesocrystals formed by tungsten oxide nanowires have been synthesized using a solvothermal method without any template. The selected area electron diffraction (SAED) analysis of the regular hexagonal mesocrystal demonstrates that the nanowires are highly ordered. Electrochemical behaviour of the mesocrystals has been evaluated by cyclic voltammograms. [ABSTRACT FROM AUTHOR]

It is highly desirable to develop new semiconductors for the photocatalytic reduction of CO2 to CH4 and CO to solve greenhouse effect and energy issues. Defect pyrochlore oxides have a flexible composition and the electron/hole mobility can be manipulated by introducing foreign cations into the structure. Through Sn doping into the defect pyrochlore oxide KNbWO6·H2O, we successfully obtained a 2-times higher photocatalytic activity for converting CO2 to CO, CH4 and O2 compared to the original KNbWO6·H2O. According to the data from UV-vis, photoluminescence, and hydroxyl radical amount-related fluorescence spectra, and CO2 adsorption, the improved photocatalytic activity can be attributed to the extended visible light response, the enhanced charge separation and the improved CO2 adsorption due to Sn doping. Our results provide a new strategy for developing high-performance photocatalysts. [ABSTRACT FROM AUTHOR]

Detecting volatile amines is a significant topic in the quality control of food and medical diagnosis. We report the first Eu-coordination polymer (CP) as a sensory material for the detection of a class of amine vapors with high selectivity and rapid response.

A new series of chiral N-heterocyclic carbene (NHC) palladium complexes were synthesized from a relatively inexpensive amino acid, l-phenylalanine. All these compounds were fully characterized by (1)H-NMR, (13)C-NMR and elemental analysis. The X-ray molecular structures of two of the complexes were reported. The catalytic activity of the four palladium complexes was successfully tested in the Sonogashira reaction under copper free conditions in air. The palladium complex 3a provided good activity in the Sonogashira coupling reaction., (This journal is © The Royal Society of Chemistry 2012)