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This work reports a facile one-pot hydrothermal route to fabricate Co-doped- MoS2/reduced graphene oxides (RGO) hybrids. The effects of Co-doping on the morphology, microstructure and electrochemical lithium storage performance of these hybrids are investigated. It is demonstrated that the rational Co-doping can change the morphologies and microstructures of the hybrids. Especially, the Co-doped-MoS2/RGO-2 prepared with 1:4 mol ratio of CoCl2 to Na2MoO4 in the hydrothermal solution shows that the numerous Co-doped MoS2 layers with shorter crystal fringes and more defect sites are well anchored on the surface of RGO, resulting in the significantly enhanced electrochemical performance for reversible lithium storage. In comparison with the MoS2/RGO, the Co-doped-MoS2/RGO-2 can not only deliver much larger reversible capacity of 1236 mAh g−1 with good cyclic stability at the current density of 100 mA g−1, but also exhibit significantly enhanced high-rate capability of 895 mAh g−1 at a high current density of 1000 mA g−1. The Co-doped-MoS2/RGO-2 also shows much higher Coulombic efficiency of 89.2% at the first cycle than MoS2/RGO (67.2%). The greatly enhanced electrochemical performance is ascribed to its robust heterostructure by hybridizing of Co-doped MoS2 layers and RGO sheets.

MoS2/reduced graphene oxide (MoS2/rGO-NP) hybrid is fabricated through one-pot hydrothermal route with mediation of a water-soluble N-methylimidazole pillar[5]arene supramolecule. MoS2 sheets with more exposed active edge sites are well dispersed on the rGO surface. Electrochemical measurements demonstrate that MoS2/rGO-NP hybrid exhibits outstanding electrocatalytic performance for hydrogen evolution reaction with a low Tafel slope of 44.5 mV/dec and significantly enhanced kinetics. Thus, the MoS2/rGO-NP hybrid holds high potential as a promising earth-abundant electrocatalyst for the cost-effective production of hydrogen.

A facile one-pot hydrothermal route with the mediation of ionic liquid (IL, [BMIM]BF 4 ) is presented to synthesize MoS 2 /nitrogen-doped graphene (MoS 2 /NG-IL) composites. It is found that as-prepared MoS 2 /NG-IL composites exhibit that the de-layered MoS 2 sheets with more exposed edge sites and defects are well anchored on the N-doped graphene. Due to the synergism between de-layered MoS 2 and N-doped graphene, MoS 2 /NG-IL composites exhibit better electrochemical performances for hydrogen evolution reaction (HER) and reversible lithium storage in comparison with MoS 2 . Especially, when 1.0 mL of IL is added in hydrothermal solution, the obtained MoS 2 /NG-IL10 displays very high electrocatalytic activity for HER with a low onset overpotential of 80 mV and a small Tafel slope of 48.0 mV/dec in 0.5 M H 2 SO 4 . As anode of lithium ion battery, MoS 2 /NG-IL10 delivers a reversible capacity as high as 1169 mAh g −1 at 100 mA g −1 and enhanced rate capability of 782 mAh g −1 at 1000 mA g −1 . After 800 cycles, a reversible capacity of about 800 mAh g −1 at 500 mA g −1 can be retained, indicating its excellent cyclic stability.

The MoS 2 /graphene composites were synthesized by a hydrothermal route in the presence of graphene oxide sheets with assistance from poly(diallyldimethylammonium chloride) (PDDA). The results of characterizations show that the MoS 2 /graphene composites exhibit a graphene-like morphology with interconnected network, in which single- or few-layer MoS 2 sheets are homogenously dispersed and well anchored on the graphene surface. The robust heterostructure and morphology of MoS 2 /graphene composites can not only provide more sites and channels for lithium ion accommodation and diffusion, but also facilitate electrolyte access. The heterostructure also maximizes the synergistic effects between MoS 2 and graphene. Therefore, MoS 2 /graphene composites exhibit significantly improved electrochemical performances for reversible lithium storage. In particular, the MoS 2 /graphene composite prepared with monomer concentration of PDDA being 0.02 mol L −1 exhibits a reversible capacity of 1100 mA h g −1 with enhanced rate capability. The reversible capacity of 856 mA h g −1 after 900 cycles at 500 mA g −1 can be remained, indicating its excellent cyclic stability.

An SnCoS4/graphene composite is synthesized via a one-step hydrothermal route. Characterizations reveal that such composite consists of SnCoS4 hybrid nanocrystals with small and uniform sizes, which are well dispersed on graphene. The electrochemical lithium storage measurements demonstrate that the SnCoS4/graphene composite exhibits a high reversible capacity of 1396 mA h g−1 at 100 mA g−1 and enhanced rate capability of 1145 mA h g−1 at 1000 mA g−1. In particular, a reversible capacity of 940 mA h g−1 can be retained after 2000 cycles at a high current density of 2000 mA g−1, indicating its excellent cyclic stability. The SnCoS4/graphene composite prepared in this work is promising as the host electrode material for high-performance lithium ion batteries.

A series of vanadium-substitutive polyoxometalate-based ionic liquids, [PyPS]6PW9V3O40, [PyPS]4PW11VO40, [PyPS]4PMo11VO40 and [PyPS]7P2W17VO62, bearing sulfo-group grafted ammonium (PyPS), are transformed to reversible thermal-response gel-type compounds. Interestingly, these gel-type compounds exhibit an obvious increase in their conductivity during the reversible phase transformation, which means that they are a novel series of reversible thermal-response gelation electrolytes. The relationship between the component elements of the polyoxometalate-based ionic liquids and their electrochemical performances has been studied. The Dawson-type compound ([PyPS]7P2W17VO62) has a higher conductivity than the Keggin-type one ([PyPS]4PW11VO40) with the same number of vanadium atoms in the structure. What’s more, the W-containing compounds ([PyPS]6PW9V3O40 and [PyPS]4PW11VO40) have higher conductivities than the Mo-containing one ([PyPS]4PMo11VO40).

MoS2/reduced graphene oxide (MoS2/rGO) composites are fabricated through a facile supramolecule-mediated hydrothermal route. The effects of the supramolecule (pillar[5]arene) on the microstructure and electrochemical lithium storage performance of the MoS2/rGO composites are investigated. It is found that the MoS2/rGO composites display a wrinkled thin flaky appearance, in which there are a lot of irregular pores and apertures. Few-layer MoS2 sheets are well dispersed and anchored on the rGO surface. When evaluated as a host material for lithium storage, the MoS2/rGO composite exhibits a much higher specific capacity of 1050–1140 mA h g−1 with excellent cyclic performance and a significantly enhanced high-rate capability of 815–875 mA h g−1 at a current density of 1000 mA g−1 in comparison with the pristine MoS2. The improved performance can be ascribed to the robust composite structure and the better synergic effects between few-layer MoS2 and rGO sheets.

A Gemini surfactant (N-dodecyl propylenediamine γ-diquaternium bromide) assisted hydrothermal route was presented for the facile synthesis of nanotile-like molybdenum disulfide/graphene (NTL-MoS2/G) hybrid. The effect of the Gemini surfactant on the microstructure and electrochemical lithium storage performance of the NTL-MoS2/G hybrid is investigated. It is found that MoS2 sheets in the hybrid display a nanotile-like morphology with 3–6 layers and are homogenously anchored on the surface of graphene. Due to their more edges, the nanotile-like MoS2 sheets facilitate lithium ion insertion/extraction and electrolyte access. The NTL-MoS2/G hybrid exhibits much higher reversible capacity with significantly enhanced cyclic stability and rate capability than the pristine MoS2. The improvement in electrochemical performances of the hybrid can also be contributed to the robust composite structure and synergistic effects between NTL-MoS2 and graphene sheets.

Few-layer molybdenum disulfide/graphene (FL-MoS 2 /GNS) composites are fabricated by a facile hydrothermal route and a post-annealing with the assistance of various cationic surfactants (dodecyltrimethylammonium bromide, DTAB; octyltrimethylammonium bromide, OTAB; and tetrabutylammonium bromide, TBAB), which have different alkyl-chain lengths and stereo configurations. The effects of these cationic surfactants on the microstructures and electrochemical performances of the FL-MoS 2 /GNS for lithium storage are investigated. It is demonstrated the cationic surfactants show some ability to control the microstructure (layer number) of FL-MoS 2 in composites. The electrochemical performances of FL-MoS 2 /GNS composites for lithium storage are greatly improved compared to the bare MoS 2 . Especially, FL-MoS 2 /GNS with ∼6 MoS 2 layers prepared with the assistance of OTAB exhibits very high reversible capacity of ∼1200 mAh g −1 with excellent cycle stability and enhanced rate capability. Electrochemical impedance spectrum also confirms that the FL-MoS 2 /GNS composite electrodes exhibit much lower electron-transfer resistance than the MoS 2 . The remarkable electrochemical performances of FL-MoS 2 /GNS composites can be attributed to the synergistic interaction between FL-MoS 2 and graphene and their quasi-3D architectures, which promote lithium diffusion, electron transfer and electrolyte access.

The unusual properties of graphene and graphene-like (GL-) layered metal dichalcogenides (LMDs, MoS2, WS2 and SnS2) have stimulated strong interest in GL-LMD/graphene composites. Heterostructures which are constructed by stacking GL-LMD and graphene together are expected to extend the usability of these 2D materials beyond graphene alone. This review will focus on recent progress in the synthesis and applications of GL-LMD/graphene composites in energy storage and conversion. The remarkable electrochemical properties of GL-LMD/graphene for reversible lithium storage are highlighted in particular. The applications of these composites in electrochemical and photochemical water splitting for hydrogen generation are also discussed.

The cobalt sulfides/graphene nanosheets (GNS) composite is prepared by a facile one-pot solvothermal route in the presence of graphene oxide sheets (GOS). XRD, SEM and TEM characterizations show that sphere-like cobalt sulfides particles with an average size of about 150 nm, which are complicated phases of CoS2, CoS and Co9S8, are highly dispersed on or wrapped in the creasy graphene. The selective nucleation and growth of cobalt sulfides particles on GOS make the particles more uniform in morphology and size. The as-fabricated cobalt sulfides/GNS composite exhibits very high electrochemical lithium storage reversible capacity of about 1018 mAh g−1. Moreover, the cobalt sulfides/GNS composite still remains reversible capacity of above 950 mAh g−1 after 50 cycles at a current density of 100 mA g−1 as well as at the different current densities from 100 to 1000 mA g−1, proving its excellent cycling durability and high-rate capability. The superior electrochemical performances of the composite may be attributed to the robust composite structure and superior conductivity, high charger mobility, large surface area and good flexibility of graphene.

A cationic surfactant-assisted hydrothermal route is developed for the facile synthesis of graphene-like MoS2/graphene (GL-MoS2/G) composites based on the hydrothermal reduction of Na2MoO4 and graphene oxide sheets with L-cysteine in the presence of cetyltrimethylammonium bromide (CTAB), following by annealling in N2 atmosphere. The GL-MoS2/G composites are characterized by X-ray diffraction, electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. The effects of CTAB concentration on the microstructures and electrochemical performances of the composites for reversible Li+ storage are investigated. It is found that the layer number of MoS2 sheets decreases with increasing CTAB concentration. The GL-MoS2 sheets in the composites are few-layer in the case of 0.01∼0.03 mol L−1 CTAB of hydrothermal solution and single-layer in the case of 0.05 mol L−1 CTAB. The GL-MoS2/G composites prepared with 0.01–0.02 mol·L−1 of CTAB solution exhibit a higher reversible capacity of 940–1020 mAh g−1, a greater cycle stability, and a higher rate capability than other samples. The exceptional electrochemical performance of GL-MoS2/G composites for reversible Li+ storage could be attributed to an effective integration of GL-MoS2 sheets and graphene that maximizes the synergistic interaction between them.

Here we develop a facile process for preparing few-layer SnS 2 /graphene (FL-SnS 2 /G) hybrid by solution-phase method employing l -cysteine as a complexing, sulfide source and reducing agent. The FL-SnS 2 /G hybrid is characterized by XRD, SEM and HRTEM. It is demonstrated that the few-layer SnS 2 with defects or disorder structure supports on graphene surface. Electrochemical tests show the FL-SnS 2 /G hybrid exhibits an extraordinary capacity of up to 920 mAh g −1 with excellent cycling stability and high-rate capability. The significant improvement in the electrochemical performances is attributed to the robust composite structure and some synergistic interactions between few-layer SnS 2 and graphene. Electrochemical impedance spectra confirm that the incorporation of graphene considerably improved the electric conductivity and electron rapid transfer of the FL-SnS 2 /G hybrid. Therefore, this new kind of FL-SnS 2 /G hybrid can be used as a promising anode material for lithium ion batteries.

A B2O3-doped SnO2 thin film was prepared by a novel experimental procedure combining the electrodeposition and the hydrothermal treatment, and its structure and electrochemical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, energy dispersive X-ray (EDX) spectroscopy and galvanostatic charge–discharge tests. It was found that the as-prepared modified SnO2 film shows a porous network structure with large specific surface area and high crystallinity. The results of electrochemical tests showed that the modified SnO2 electrode presents the largest reversible capacity of 676 mAh g−1 at the fourth cycle, close to the theoretical capacity of SnO2 (790 mAh g−1); and it still delivers a reversible Li storage capacity of 524 mAh g−1 after 50 cycles. The reasons that the modified SnO2 film electrode shows excellent electrochemical properties were also discussed. Keywords: Modified SnO2 film, Porous structure, Electrodeposition, Hydrothermal treatment, Lithium-ion batteries

Pt–CeO2/C catalysts were synthesized by a one-step microwave polyol process and compared with Pt/C (E-TEK) catalyst in terms of the electrochemical activity for methanol oxidation using the cyclic voltammetry and chronoamperometry. The results demonstrated that Pt–CeO2/C catalysts exhibited lower onset potential, higher current peak and better stability for methanol electrooxidation than Pt/C (E-TEK) catalyst. The effect of ceria on the catalytic activity was investigated by electrochemical measurements and the highest electrochemical activity was obtained at the molar ratio of Pt to Ce by 2:1. The preliminary mechanism of the enhanced electrocatalytic performance for methanol oxidation was discussed.

An electrodeposition route for preparation of well-controlled magnesium hydroxide nanostructure using sodium acetate as structure-directing agent was presented. The magnesium hydroxide thin films were characterized by XRD, SEM and TEM. The influence of synthesis parameters on the morphological characteristics and size of magnesium hydroxide thin films deposited from nitrate bath was investigated, such as concentration of sodium acetate additive and applied potential. A possible mechanism responsible for morphologies evolution of thin films was also elucidated. This electrochemical process may be extended to fabricate other nano-/mesostructures with diverse morphologies and unique properties under convenient and mild conditions.

Facile, scale-up, and controllable fabrication of lamellar-like Mg(OH) 2 on a magnesium substrate through natural oxidation of Mg metal in formamide/water mixtures has been demonstrated. The one-step, wet-chemical approach has displayed well-controlled growth of densely packed magnesium hydroxide with large-area homogeneity and uniform morphology. The chemical-liquid-deposition process, an analogue to the widely used chemical-vapor-deposition technique, has been well developed for production of specific morphological Mg(OH) 2 through continuous supply, transport, and thermal decomposition of magnesium complexes in a liquid phase. The formation mechanism of lamellar-like Mg(OH) 2 was also discussed based on experimental phenomena.

Pr(OH) 3 nanorods with uniform diameter of 12 nm and different lengths ranging from 50 to 220 nm were successfully prepared via a facile and rapid microwave-assisted hydrothermal method. Pr 6 O 11 nanorods were also obtained from calcination of the as-prepared hydroxide nanorods as precursors at 500 °C for 6 h. The results showed that the Pr(OH) 3 with hexagonal phase and Pr 6 O 11 nanorods with cubic phase have high crystallinity and purity. The mechanism for the microwave-assisted hydrothermal synthesis of Pr(OH) 3 nanorods was preliminarily presented.

Highly textural lamellar mesostructured Mg(OH)2 thin films were obtained through one-step cathodic reduction of magnesium nitrate bath without any surfactant template at room temperature. Its microstructure, stability and morphology were investigated using XRD, TEM, FT-IR, thermal analysis and SEM technique respectively. The results indicate that the porous hydroxide/oxide materials have highly textural lamellar structures with layer spacing around 3.4 nm. The possible formation mechanism has been discussed.

A carbon supported hollow Pt nanosphere electrocatalyst was prepared at room temperature in a homogeneous solution employing cobalt metal nanoparticles as sacrificial templates. TEM measurements showed that carbon supported Pt nanospheres were coreless and composed of discrete Pt nanoparticles with the crystallite size of about 2.2 ± 0.2 nm. XRD results showed that the hollow Pt nanospheres had a face-centered cubic structure. Electrochemical measurements demonstrated that the carbon supported hollow Pt nanosphere electrocatalyst exhibited enhanced electrocatalytic performance for methanol oxidation compared with carbon supported solid Pt nanoparticles.

Pt/C catalysts with different mean size of Pt particles were prepared by a microwave-assisted polyol process and characterized by TEM and XRD. The effects of the synthesis solution pH on Pt particles size and distribution, and their activity for methanol electrooxidation were investigated. Pt nanoparticles were small and uniform with mean size of 2.7 nm under the pH of 9.5. Pt/C catalyst showed high activity for methanol electrooxidation.

The Ru/C nanocomposites with Ru loadings of 20∼60 wt.% were prepared by the polyol process in the presence of XC-72 carbon. TEM observations indicated that Ru nanoparticles were uniform with the average size of about 3.1∼3.5 nm, and highly dispersed on the carbon surface. After electrochemically oxidization from Ru nanoparticles to the pseudocapacitive oxide–hydroxide form, the specific capacitances of these composites were calculated by cyclic voltammetry. It was found that these composites exhibited much higher specific capacitances in comparison with the XC-72 carbon.

Acetate-stabilized Pt nanoparticles supported on carbon were prepared by a microwave heating polyol method, in which a small amount of sodium acetate solution was added as a stabilizing agent in the synthesis solution. The Pt/C catalysts were characterized by energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and X-ray diffraction (XRD). It was found that the Pt nanoparticles were small and uniform in size, and highly dispersed on XC-72 carbon supports. The mean size of the Pt particles was 5.1, 4.3, 3.5 and 2.8 nm, respectively, correspondingly for adding 0, 0.1, 0.3 and 0.5 mL of 1.0 M sodium acetate solution in 50 mL of the synthesis solution. The effects of the amount of acetate solution added on the Pt particle size and size distribution were investigated. The electrochemical measurements demonstrated that the Pt/C catalysts prepared in this way exhibited a much higher electrocatalytic activity for methanol electro-oxidation than a comparative Pt/C catalyst prepared without adding acetate.

Pt/C electrocatalysts were prepared from a solution of H2PtCl6 in ethylene glycol in the presence of XC-72 carbon by adding a small amount of sodium acetate as stabilizer. Repeated TEM images showed that the platinum nanoparticles were small and uniform in size and highly dispersed on XC-72 carbon supports when a small amount of sodium acetate solution was added to the synthesis solution. The Pt/C electrocatalysts exhibited very high electrocatalytic activity for liquid methanol oxidation. The effects of adding acetate on Pt particle size and size distribution are discussed. It is demonstrated that acetate can be used as a good stabilizer for preparing Pt/C catalyst with fine and uniform Pt particles.

Nanocrystalline cadmium peroxide thin film has been electrodeposited on indium doped tin oxide glass substrate from aqueous solution at room temperature. The grain size of the nanocrystals of the film is estimated from XRD and is about 14 nm. The deposits are decomposed at 228 °C by formation of CdO, releasing plentiful heat at same time. The band-gap of the nanocrystalline CdO film made from decomposition of electrodeposited CdO2 is around 2.4 eV. Keywords: Electrodeposition, Metal peroxide, Metal oxide, Nanocrystal, Semiconductor

Pt nanoparticles with different mean sizes supported on carbon nanotubes were synthesized by microwave heating ethylene glycol solutions of platinum salt with different pH in present of CNTs as supports. TEM examinations showed that Pt particles become smaller and more uniform when the synthesis pH increased from 3.4 to 9.2. The mean particle size was 5.8, 5.2, 3.4 and 2.7 nm when the synthesis pH was 3.6, 5.8, 7.4 and 9.2, respectively. The effects of the pH on Pt particle size and distribution were investigated. The pH was an important factor that influenced the particle size. Pt particles size could be thus selected by adjusting the synthesis solution pH. Pt/CNTs with suitable and uniform Pt particle size could be obtained. Electrochemical measurements showed that the Pt/CNTs catalyst prepared from the synthesis solution pH of 7.4 exhibited better performances for methanol electrooxidization than other samples.

Pt nanoparticles supported on Vulcan XC-72 carbon and carbon nanotubes (CNTs) were prepared by a microwave-assisted polyol process. The catalysts were characterized by TEM, XRD and XPS. The Pt nanoparticles, which were uniformly dispersed on carbon, were 2–6 nm in diameter. The Pt/C catalysts prepared as such displayed the characteristic diffraction peaks of a Pt fcc structure. XPS analysis revealed that the catalysts contained mostly Pt(0), with traces of Pt(II) and Pt(IV). The electroreduction of oxygen was studied by cyclic voltammetry. It was found both Pt/C catalysts had high electrocatalytic activity in the oxygen reduction reaction. Test runs on a single stack proton exchange membrane (PEM) fuel cell showed that these electrocatalysts are very promising for fuel cell applications.

CdS semiconductor nanorods doped with different contents of manganese have been successfully prepared by the hydrothermal reaction of CdCl 2 · 2.5H 2 O and MnCl 2 · 5H 2 O with (NH 4 ) 2 S in aqueous solution at 180 °C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that these samples are almost total rod-like with approximately identical diameter around 20 nm and the maximal length up to 300 nm. Novel optical properties have been observed via UV–Visual absorption spectra and photoluminescence (PL) spectra. The absorption shoulder and the two luminescence emission peaks have shifted in different way as the mole ratio of manganese in the nanorods varies. A possible PL mechanism is suggested to explain this spectroscopy behavior.

Nanocomposites of carbon nanotubes (CNTs) with Sb and SnSb0.5 particles were prepared by chemical reduction of SnCl2 and SbCl3 precursors in the presence of CNTs. SEM and TEM imaging showed that the Sb and SnSb0.5 particles are uniformly deposited on the CNT exterior and in the CNT web. These CNT–metal composites are active anode materials for lithium ion batteries, showing improved cyclability compared to unsupported Sb and Sn–Sb particles and higher reversible specific capacities than CNTs. The reversible capacities were as high as 462 mAh/g for CNT–36 wt.% Sb and 518 mAh/g for CNT–56 wt.% SnSb0.5. After 30 cycles, the capacity was 62.1% of the initial capacity for the former and 67.2% of the initial capacity for the later. In comparison Sb and SnSb0.5 could only retain 17.7 and 23.5%, respectively of their initial capacities in the same number of cycles. The improvement in cyclability may be attributed to the nanoscale dimension of the metal particles and CNTs’ role as a buffer in relieving the mechanical stress induced by specific volume changes in electrochemical lithium insertion and extraction reactions.

A simple chemical method was employed to coat carbon nanotubes (CNTs) with a layer of Co-B amorphous alloy. This technique involved a redox reaction using KBH4 as reducing agent and Na-2[Co(OH)(4)] complex as cobalt precursor. The amorphous character of the Co-B alloy was confirmed by high-resolution transmission electron microscopy (HRTEM) and Xray diffractogram analysis (XRD). These coated carbon nanotubes may be of great interest in magnetic research and as highly active catalysts in heterogeneous catalysis. (C) 2002 Published by Elsevier Science B.V.

The effects of the surface treatment of the hydrogen storage alloy on the activation property and cycle life of nickel/metal-hydride (Ni/MH) batteries were investigated by means of the electrochemical impedance spectra. It was found that the oxide layer on the alloy surface affected its electrochemical properties and catalysis for the oxygen combination. Therefore, Ni/MH battery employed the untreated alloy as negative electrode material exhibited bad activation property, short cycle life and high internal pressure. Because of the improvement in the metal hydride electrode electrochemical characteristics and catalysis for oxygen recombination by the surface treatment of the alloy in 0.02 M KBH 4 +6 M KOH or 6 M KOH solution, the battery used the treated alloy as negative exhibited good activation, long cycle life and low internal pressure. The composition and dissolution of the alloy surface were analyzed by an electron probe microanalysis (EPMA) and induced coupled plasma spectroscopy (ICP). It was found that the Ni-rich surface layer was an important factor to improve the activation and cycle life of battery.

Metal hydride (MH) electrodes are treated in an alkaline solution containing potassium borohydride (KBH 4 ) to increase the discharge capacity and high-rate dischargeability and to improve the activation, electrocatalytic activity and cyclic stability. XPS and ICP analyses indicate that the nickel oxide on the surface of the hydrogen-storage alloy is partly reduced by the reduction treatment. Part of the atomic hydrogen released during this treatment is adsorbed on the surface of the alloy and penetrates into the lattice to form the hydride. It is found that a Ni-rich surface layer with a high electrocatalytic activity for the electrode reaction is produced because of the preferential dissolution of Mn and Al. In addition, the specific surface area of the treated alloy is increased. An AA-size Ni–MH battery has been assembled with the treated MH electrode as its negative electrode. The battery displays a superior high-rate dischargeability and better low-temperature characteristics.

After years of development, improvement in the electrochemical properties of MoS2 through structural modifications has reached its limit. Further improvements in the Li+ storage properties of MoS2 must be based on an understanding of the Li+ storage mechanism in MoS2. On this basis, we have developed a novel ternary composite of graphene, MoS2 nanosheets and a small amount (1 wt%) of silver nanoclusters (NCs; MoS2/G/Ag). The presence of the Ag NCs in the composite is, however, instrumental and serves several purposes: immobilization of sulfur, increased association with Li+ and increased spacing between graphene sheets. The presence of this small amount of Ag NCs was able to increase the Li+ storage capacity of MoS2 by 60% (with a discharge capacity of ~1300 mAh g−1 at 0.5 A g−1 compared with 800–850 mAh g−1 for a MoS2/graphene composite without the Ag NCs (MoS2/G)). The MoS2/G/Ag composite also exhibited a very impressive rate performance: discharge capacities of 1040 and 850 mAh g−1 at the very high current densities of 1 and 5 A g−1, respectively (the corresponding values from MoS2/G without the Ag NCs are 790 and 580 mAh g−1). A high-capacity alternative to graphite electrodes commonly used in lithium-ion batteries has been made by scientists in Singapore and China. Molybdenum disulfide (MoS2) has a two-dimensional layered structure resembling graphite, but with a significantly higher affinity for lithium ions. When combined with graphene, a conductive sheet-on-sheet material is formed which maintains a high capacity over many charge–discharge cycles. Jim Yang Lee and colleagues now report a way that uses silver nanoparticles to raise the lithium-ion storage of MoS2/graphene oxide electrodes even higher, by over 60%. The team employed a simple and scalable carbon monoxide reduction reaction to insert uniform layers of sub-2-nanometre silver spheres between the MoS2 and graphene sheets. The expansion in interlayer distance and the improved sulphur immobilization and lithium-ion association are likely causes for the jump in storage capacity. A minute presence of silver nanoclusters in a MoS2 nanosheet–graphene composite was found to significantly increase the reversibility of Li+ storage in the composite through Li+ association, pillaring of graphene and the immobilization of S species.

By the introduction of trimethylammonium groups at both upper and lower rims, a cationic water-soluble pillar[5]arene was prepared, which forms a stable 1 : 1 host–guest complex with sodium 1-octanesulfonate in water.

A one-pot synthesis of quinolines via molecular iodine-catalyzed and air-mediated tandem condensation/imino-Diels–Alder/isomerization/oxidation of simple readily available amines, aldehydes, and alkynes has been developed. This methodology was extended to synthesize quinazolines from two molecules of amines and two molecules of glyoxalates.

A facile process was developed to synthesize MoS(2)/graphene nanosheet (GNS) composites by a one-step in situ solution-phase method. These MoS(2)/GNS composites therefore exhibit extraordinary capacity, i.e., up to 1300 mA h g(-1), and excellent rate capability and cycling stability as an anode material for lithium ion batteries.

Pr(OH)3 nanorods with 12–30 nm in diameter and 30–300 nm in length were prepared by a hydrothermal process. The as-synthesized product was characterized by XRD, TEM, and TG-DTA. The results showed ...

Carbon-supported platinum and ruthenium nanoparticles were synthesized by a microwave-assisted polyol heating process. TEM observations showed that the Pt and Ru particles prepared as such have uni...

The synthesis of graphene-based composite materials for Li-ion batteries using an in situ growing technique is first proposed in this work. Graphene frame supported silicon@graphitic carbon granules were obtained through a one-step solid-state reaction using iron phthalocyanine (FePc) and silicon nanoparticles (SiNPs) as the precursors. Nitrogen-doped graphene was grown in situ around the SiNPs by pyrolyzing and re-carbonizing FePc, and a cross-linked graphene frame network was gradually formed. Simultaneously, SiNPs were wrapped by a thin graphitic carbon layer, and the strong interconnections between the graphene, graphitic carbon and SiNPs led to a spontaneous self-assembly process, resulting in the formation of μm scale granules with available nanoporosities and irregular channels. The self-assembled granules with excellent electrical conductivity can effectively accommodate the volume change of the SiNPs during the repeating discharge–charge processes, therefore high capacity, long cycle life, high Coulombic efficiency and superb rate capability have been realized. The synthesis strategy is facile, safe, low-cost and can be easily industrialized, providing a broadly applicable route for the in situ synthesis of more functional graphene-based composite materials.

MoS2/graphene composites were synthesized through the concurrent reducing of (NH4)2MoS4 and graphene oxide sheets with assistance of different cationic surfactants (DTAB, OTAB and TBAB) followed by heat treatment in a nitrogen atmosphere. The effects of the three cationic surfactants on the microstructures and electrochemical performances of the composites for reversible lithium storage were investigated. The MoS2 in the composites prepared with assistance of DTAB or OTAB displays single-/few-layer structure, while the layered MoS2 sheets with about 6–7 layers are observed in the composite prepared with assistance of TBAB. The former two composites exhibit greatly enhanced electrochemical performance for reversible Li+ storage. In particular, MoS2/graphene composite prepared with assistance of OTAB delivered a high reversible capacity of 1056 mA h g−1 with excellent cycle stability and good rate capability. The significant improvement in the electrochemical performances is attributed to the roubest composite structure and the synergistic interactions between graphene and single-/few-layer MoS2. This work also presented a facile process to prepare MoS2/graphene composites, in which the layer number of MoS2 sheets could be adjusted to a certain extent by using different cationic surfactants.

Conservation of the weathered historic calcareous stones by apatite was studied. By mimicking the growth of bone, calcium and phosphorus were introduced into the weathered stone and then mineralized at room temperature. The conservation efficiency was investigated by SEM, EDX, XRD, “Scotch Tape Test” (STT), compressive strength test, capillary water uptake test, water vapor permeability test and weather resistance test. The results of SEM, EDX and XRD showed that the produced bone-like hydroxyapatite could bind the introduced calcium carbonate and the weathered stone blocks together. The test results also indicated that this conservation method could improve the surface strength, compressive strength and weather resistance of the treated samples significantly. Besides, due to the porous nature of the bone-like apatite, the water vapor permeability of the treated stone was not affected and its “breathe function” was retained. Therefore, the proposed method will be a good candidate for the in situ conservation of historic calcareous stones.