Yamin Feng

CNT-network modified Ni nanostructured arrays for high performance non-enzymatic glucose sensors

Ni nanostructured arrays (NAs) modified by entangled carbon nanotube (CNT) networks have been fabricated via a facile chemical vapor deposition (CVD) approach and applied as an electrode for non-enzymatic glucose sensors for the first time. Compared with previously reported Ni-contained biosensors, the electrode of CNT/Ni NAs possess higher performance for the detection of glucose, showing a low detection limit (1 μM, S/N = 3), a wide linear range (0.5–10 mM) and quite high sensitivity (∼1381 μA mM−1 cm−2). In addition, other excellent properties of the CNT/Ni NAs electrode, such as good reproducibility, long-term stability and anti-interferences, are demonstrated as well. The good analytical capability, low cost and facile preparation method make CNT/Ni NAs promising for amperometric non-enzymatic glucose detection.

Three-dimensional Ni/SnOx/C hybrid nanostructured arrays for lithium-ion microbattery anodes with enhanced areal capacity.

The areal capacity of lithium-ion microbatteies (LIMBs) can be potentially increased by adopting a three-dimensional (3D) architectured electrode. Herein, we report the novel 3D Ni/SnOx/C hybrid nanostructured arrays that were built directly on current collectors via a facile hydrothermal method followed by a calcination-reduction process. Branched SnO2 nanorods grew uniformly on Ni2(OH)2CO3 nanowall arrays, resulting in the formation of precursors with a 3D interconnected architecture. By using ethylene glycol as the reducing agent, the glucose-coated SnO2/Ni2(OH)2CO3 precursors were evolved into an interesting 3D Ni/SnOx/C hybrid nanostructured arrays within the calcination treatment. Compared to conventional 2D SnOx/C nanorod arrays, the electrode of 3D Ni/SnOx/C hybrid nanostructured arrays exhibited enhanced lithium storage capacity per unit area, preferable rate capability and improved cycling performance when tested for LIMBs. The superior performance might be attributed to the open-up Ni frameworks that can not only serve as effective channels for electrons transport and Li+ diffusion but also help to accommodate the large volume changes upon lithiation/delithiation.

Preparation and gas-sensing property of ultra-fine NiO/SnO2 nano-particles

Novel ultra-fine NiO/SnO2 nano-particles (NPs) have been fabricated by creatively using carbon black (CB) as a frame and dispersing agent and applied as gas-sensing materials. In a typical synthesis, a precursor composed of mixed NiO/SnO2 NPs and CB was initially prepared. Subsequently, the ultra-fine NiO/SnO2 NPs were obtained by a thermal treatment of the precursor. The final products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and Brunauer Emmett Teller N2 adsorption–desorption analysis. The ethanol-sensing tests revealed that the ultra-fine NiO/SnO2 NPs used as gas sensors have a quick response/recovery capability (response time: 2–40 s; recovery time: 3–20 s) within a detecting range of 5–100 ppm at an operating temperature of 300 °C; strikingly, the response/recovery times are quite short (2 s and 3 s, respectively) even under the detection limit of 5 ppm. As demonstrated, the ultra-fine NiO/SnO2 NPs are highly promising for real-time monitoring gas sensor applications.

Building smart TiO2 nanorod networks in/on the film of P25 nanoparticles for high-efficiency dye sensitized solar cells

We herein present a useful and novel strategy to redesign photoanodes by building smart TiO2 nanorod networks in and on a film of P25 nanoparticles (NPs) to optimize the comprehensive performance of dye-sensitized solar cells (DSSCs). By using a doctor-blade method followed by a facile hydrothermal treatment, an interesting hierarchical double-layered film consisting of P25 NPs and TiO2 nanorods (NRs) was fabricated on a fluorine-doped tin oxide (FTO) substrate. In our strategy, P25 NPs (underlayer) with a large surface area can potentially enable a large amount of dye absorption while TiO2 NRs (overlayer) as the scattering part would effectively strengthen the light harvesting ability. Moreover, TiO2 NRs inserted into the P25 NP film also provide conducting networks for fast photogenerated electron transport. As demonstrated in photoanodes for DSSCs, this hierarchical double-layered photoanode indeed exhibits superior DSSC performance to that of a pure P25 NP film; the photovoltaic conversion efficiency increases up to 8.62% under illumination of one sun (AM 1.5 G, 100 mW cm−2), which is significantly better than 6.12% for the pure P25 NP photoanode. This work highlights the significance of the rational design of photoanode electrodes for enhanced energy conversion applications.

Effect of pH on the self-assembly of three Cd(II) coordination compounds containing 5-(4-pyridyl)tetrazole: syntheses, structures, and properties

Hydrothermal reactions of CdSO4, 4-cyanopyridine, and sodium azide yield three metal coordination compounds via controlling the pH, [Cd2(4-ptz)(SO4)(OH)(H2O)2](H2O) (1) [Cd2(4-ptz)(SO4)(OH)(H2O)]n (2), and known [Cd2(4-ptz)2(H2O)4](H2O)2 (3) (4-ptz = 5-(4-pyridyl)tetrazole). The in situ [2 + 3] cycloaddition reaction of nitrile and azide in the presence of Cd(II) produces the multidentate 4-ptz in these compounds. X-ray diffraction results indicate that metal centers in 1 are linked by 4-ptz–, , and OH− in their respective μ5-, μ2-, μ3-bridging modes, forming a 3-D coordination polymer. For 2, although the same raw materials are used, the component anions are linked to Cd(II) centers in completely different ways, i.e. for 4-ptz− in μ3−, in μ5-, and OH− in μ3-bridging modes, forming another 3-D coordination network. Thermal stabilities and photoluminescent properties of 1 and 2 have also been investigated. Graphical abstract Three cadmium(II) coordination compounds were synthesized via controlling the pH in the in situ [2 + 3] cycloaddition reaction of CdSO4, 4-cyanopyridine, and sodium azide under hydrothermal treatment. Mononuclear 3 was obtained at weak acid solution pH 6.0~7.0, but 3-D coordination polymers 1 and 2 were preferred in weak alkaline conditions from pH 7.0 to 9.0.

Topological analysis of the three‐dimensional coordination polymer poly[(μ4‐azido)[μ4‐5‐(pyridin‐4‐yl)tetrazolido]disilver(I)]

The title compound, [Ag2(C6H4N4)(N3)]n, was obtained under hydrothermal conditions at 433 K. The asymmetric unit of the orthorhombic space group (Pna21) consists of two Ag(+) cations, an anionic 5-(pyridin-4-yl)tetrazolide (4-ptz(-)) ligand and an anionic azide ligand. Both Ag(+) centres are coordinated by four N atoms, forming a distorted tetrahedral coordination environment. When all the component ions are viewed as 4-connected nodes, the whole three-dimensional network can be regarded topologically as a new kind of 4,4,4,4-connected net with the Schläfli symbol (4.8(5))(4(2).8(4))(4(3).8(3))2.

Benzene-1,3,5-tricarb­oxy­lic acid–5-(pyridin-1-ium-3-yl)-5H-1,2,3,4-tetra­zol-5-ide (1/1)

The asymmetric unit of the title compound, C6H5N5·C9H6O6, comprises a full molecule each of neutral trimesic acid (tma) and zwitterionic 5-(pyridin-1-ium-3-yl)-5H-1,2,3,4-tetrazol-5-ide (ptz). The components are linked into a two-dimensional layer by a combination of O—H⋯O, O—H⋯N, N—H⋯O and N—H⋯N hydrogen bonds parallel to the (10) plane. Layers comprising alternating rows of tma and ptz are linked into a three-dimensional network by C—H⋯O and π–π interactions between tma and tetrazolate rings [centroid–centroid distance = 3.763 (2) Å], and between pyridinium and tetrazolate rings [centroid–centroid distance = 3.745 (2) Å].