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Co 2 P/graphene nanocomposites with graphene nanosheets anchoring with Co 2 P nanorods are prepared by a facile solution method. Their property as anode materials for lithium ion batteries is tested and compared with that of Co 2 P nanorods without anchoring on graphene. Compared to Co 2 P counterpart, Co 2 P/graphene nanocomposites exhibit more enhanced performance in Li-ion reversible capacity and cycleability. It is interesting that in both galvanostatic and rate cyclic performance, capacities show evidently increasing trend with increasing the cycle number, and then keep at an ultimate level around 800–900 mA h g −1 which is much higher than the theoretical capacity of Co 2 P and graphene. This enhanced property may concern with the abundant microspores in Co 2 P/graphene nanocomposites and the catalytic decomposition of solid electrolyte interphase (SEI). The effective combination of Co 2 P nanorods with graphene not only reduces the particle aggregation but also complement the limitations of Co 2 P as anode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Efficient and economical hydrogen evolution reaction (HER) from water splitting holds a bright prospect for clean energy. Replacement of expensive Pt-based catalysts with earth-abundant catalysts is beneficial for this field. In this study, nanoscale magnetic metal phosphides including Co 2 P, Co 1.33 Ni 0.67 P and Ni 2 P nanorods are synthesized by a facile solution method. Their HER activities and stabilities on glassy carbon and Ti electrodes are investigated. The Co 2 P nanorods deposited on glassy carbon electrodes are found to show higher activity and better reversibility than the C o1.33 Ni 0.67 P and Ni 2 P counterparts. Nevertheless, the Co 1.33 Ni 0.67 P and Ni 2 P samples on Ti electrodes gain a significant activity promotion after annealing in H 2 /Ar atmosphere. Investigation of the Tafel curves shows that the Co 2 P nanorods on glassy carbon have the lowest Tafel slope while their exchange current density on Ti electrode exhibits a high value which is comparable to that of Pt electrode. Furthermore, the cyclic voltammetric tests show that the reversibility of annealed Co 2 P on Ti electrode is the best, which emphasizes the superiority of Co species in catalyzing HER reaction. Finally, the three magnetic metal phosphide catalysts are found to exhibit good stabilities in acidic conditions according to the galvanostatic testing results. [ABSTRACT FROM AUTHOR]

In this paper, we report the anisotropic optical and catalytic properties of wurtzite-type hexagonal CoO (h-CoO) nanocrystals, an unusual nanosized indirect semiconductor material. h-CoO nanoplates and nanorods with a divided morphology have been synthesized via facile solution methods. The employment of flash-heating and surfactant tri-n-octylphosphine favors the formation of plate-like morphology, whereas the utilization of cobalt stearate as a precursor is critical for the synthesis of nanorods. Structural analyses indicate that the basal plane of the nanoplates is (001) face and the growth direction of the nanorods is along the c axis. Moreover, the UV–vis absorption spectra, the corresponding energy gap and the catalytic properties are found to vary with the crystal shape and the dimensions of the as-prepared h-CoO nanocrystals. Furthermore, remarkable catalytic activities for H2 generation from the hydrolysis of alkaline NaBH4 solutions have been observed for the as-prepared h-CoO nanocrystals. The calculated Arrhenius activation energies show a decreasing trend with increasing extension degree along the 〈001〉 direction, which is in agreement with the variation of the charge-transfer energy gap. Finally the maximum hydrogen generation rate of the h-CoO nanoplates exceeds most of the reported values of transition metal or noble metal containing catalysts performing in the same reaction system, which makes them a low-cost alternative to commonly used noble metal catalysts in H2 generation from the hydrolysis of borohydrides, and might find potential applications in the field of green energy. [ABSTRACT FROM AUTHOR]

Abstract: We report the excellent catalytic performance of CoO nanocrystals on the catalytic hydrolysis of alkaline NaBH4 solutions. CoO nanocrystals with octahedral and near-spherical shapes are synthesized using a facile chemical solution method that employed cobalt acetate tetrahydrate as metal precursor in the presence of oleylamine. The octahedral CoO nanocrystals typically have a size of 40–50 nm, while the near-spherical nanocrystals have a size varying from 8 to 13 nm. Both of them have a face centered cubic (fcc) crystalline phase. Catalytic tests show that the as-synthesized CoO nanocrystals exhibit very high activities for the H2 generation from the hydrolysis of alkaline NaBH4 solutions. The maximum hydrogen generation rate of the as-synthesized CoO nanocrystals exceeds most reported values of transition metal or noble metal contained catalysts performed in alkaline NaBH4 solutions. The influences of shape on the catalytic behaviors of as-synthesized CoO nanocrystals are also compared and analyzed. The results presented in this study indicate that CoO nanocrystals are a promising candidate to replace noble metal catalysts in the H2 generation from the hydrolysis of borohydrides. [Copyright &y& Elsevier]

A facile nonaqueous injection method has been developed for the construction of one-dimensional nanostructure consisting of a magnetic alloy (Ni–Cu) core and a plasmonic alloy (Au–Cu) shell. The obtained Ni–Cu@Au–Cu nanowires exhibit tunable optical and magnetic properties. [ABSTRACT FROM AUTHOR]

Amorphous ZnSnO 3 -C hollow microcubes have been produced by calcination of the pre-synthesized ZnSn(OH) 6 hollow microcubes in argon, followed by the surface decoration of carbon. The calcination temperature plays an important role in the phase and morphology of the obtained products. ZnSnO 3 -C hollow microcubes have an average edge length of about 1.0 μm with the shell thickness of approximate 145 nm. When adopted as the anode materials for lithium ion batteries, amorphous ZnSnO 3 -C hollow microcubes manifest greatly enhanced electrochemical properties compared to amorphous ZnSnO 3 hollow and solid counterparts. After 50th cycles, a high reversible capacity of 703 mA h g −1 can be obtained for amorphous ZnSnO 3 -C hollow microcubes at the current density of 100 mA g −1 . The superior lithium storage properties of ZnSnO 3 -C are due to its unique hollow structure with large specific surface area, the modification of carbon and the amorphous characteristic. [ABSTRACT FROM AUTHOR]