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Nanostructures, especially nanowires with high aspect ratios, have attracted much attention due to their potential applications, such as interconnects in nanofabrication, [1] optoelectronics, [2] nanosensors, [3] nano-biotechnology, [4] and electron emitters. [5][6][7] It was reported that the properties of the nanostructures were affected by their size and morphology, [8][9][10] which subsequently prompted extensive efforts to control them. The synthesis of metal nanostructures, such as nanorods and nanowires of copper, silver, and gold, has been demonstrated using various methods. [7,[11][12][13][14][15][16][17][18][19][20] For these metals, face-centered cubic (fcc) structures were synthesized, particularly with fivefold twinned symmetry, which was done mostly in the solution phase. The randomness inherent to this solution-phase synthesis, however, has largely prevented the resulting nanostructures from being integrated into highdensity electronic and optoelectronic devices. In fact, welldefined five-twinned fcc nanostructures vertically grown on a substrate surface have not been possible except in a few cases involving copper nanowires (CuNWs) and copper nanobats. [7,21] In this Communication, we present a detailed structural analysis, based on a transmission electron microscopy (TEM) and electron diffraction (ED) study, of CuNWs grown by chemical vapor deposition (CVD) that not only have fivefold-twinned structures but are also suitable for integration into devices. The analysis unveils new details of the five-twinned structure and elucidates the growth mechanism of the CuNWs, specific to the special precursor used, which does not require templates or catalysts. The electron emission characteristics of the CuNWs were investigated and they indicate that the CuNWs are a promising electron emitter. An array of CuNWs was grown on a patterned silicon substrate to show that the present CuNW growth mechanism is suitable for practical application. The array was used in a proofof-principle experiment to demonstrate a field emission display. The CuNWs were prepared by a method previously described that uses Cu(etac)[P(OEt) 3 ] 2 as a precursor, where etac is ethyl 3-oxobutanoate and P(OEt) 3 is triethyl phosphite.[21] Typically, the CuNWs of 70-250 nm diameter were grown on Si at substrate temperatures of 200-300 8C under 0.1-1.0 Torr using argon as a carrier gas. The nanowires were also grown on other substrates, including glass, metal, metal oxide, and polymer. The diameters and lengths of the CuNWs were controlled by the processing conditions, such as the substrate material, substrate temperature, deposition time, and precursor feeding rate. Figures 1a-c show scanning electron microscopy (SEM) images of CuNWs grown vertically on a Si substrate at 250 8C, indicating that the nanowires have five side planes forming a pentagonal pyramid tip. Figure 1d shows the copper seed formation at an early stage of nanowire growth. The structure of the CuNWs was analyzed using TEM. Figure 2 shows TEM images of a CuNW and correspo...

The structure and activity of Mo/Silicalite‐1 (MFI, Si/Al=∞) were compared to Mo/H‐ZSM‐5 (MFI, Si/Al=15), a widely studied catalyst for methane dehydroaromatisation (MDA). The anchoring mode of Mo was evaluated by in situ X‐ray absorption spectroscopy (XAS) and density functional theory (DFT). The results showed that in Mo/Silicalite‐1, calcination leads to dispersion of MoO3 precursor into tetrahedral Mo‐oxo species in close proximity to the microporous framework. A weaker interaction of the Mo‐oxo species with the Silicalite‐1 was determined by XAS and DFT. While both catalysts are active for MDA, Mo/Silicalite‐1 undergoes rapid deactivation which was attributed to a faster sintering of Mo species leading to the accumulation of carbon deposits on the zeolite outer surface. The results shed light onto the nature of the Mo structure(s) while evidencing the importance of framework Al in stabilising active Mo species under MDA conditions.

Herein, we present the upscaled synthesis of nanoparticulate Li 4 Ti 5 O 12 (LTO) by means of flame spray pyrolysis (FSP), yielding high phase purity and appropriate morphology for application as high-power lithium-ion anode material. Electrodes based on this optimized LTO nanopowder, carboxymethyl cellulose (CMC) as binder, and copper as current collector revealed excellent rate performance, providing specific capacities of 133, 131, 129, 127, 124, and 115 mAh g −1 when applying C rates of 1C, 2C, 5C, 10C, 20C, and 50C, respectively. Targeting the commercial application of thus synthesized nanoparticles, we optimized also the electrode composition, comparing three different binding agents (CMC, PVdF, and poly(acrylic acid), PAA) and substituting the copper current collector by aluminum. The results of this comparative analysis show, that the combination of nanoparticulate LTO, CMC, and an aluminum current collector appears most suitable toward the realization of environmentally friendly and cost-efficient lithium-ion anodes, presenting very stable cycling performance for more than 1000 cycles at 10C without substantial capacity decay. While lithium-ion batteries are already the energy storage device of choice for portable electronic devices, they are recently gaining importance for large-scale applications like (hybrid) electric vehicles and stationary energy storage.1-5 However, beside advances regarding the energy density, such applications still require an improved safety, long-term cycling stability, as well as enhanced power densities with respect to state-of-the-art lithium-ion cells, commonly employing graphite as anode material.1-5 Spinel-structured Li 4 Ti 5 O 12 (LTO), reported for the first time by Colbow et al. in 1989, 6 is presently considered as one of the most promising alternative anode materials for realizing safer, long-lasting, high power lithium-ion batteries 7-13 and is, for such reasons, already utilized in commercial cells.2 While the enhanced safety and advanced long-term cycling stability, resulting from the relatively higher lithium (de-)insertion potential and the negligible volume variation upon (de-)lithiation, 14-17 respectively, are, to a great extent intrinsic to LTO, the high power performance, i.e., the rate capability, of the material is highly dependent on the utilized synthesis method and the resulting particle size and morphology. 9,13,[18][19][20][21] Indeed, downsizing the particle size to the nanometer-scale resulted in excellent power performance, 21-25 allowing (dis-)charging LTObased electrodes in as little as a few seconds. However, one of the major challenges toward the commercialization of nano-sized LTO is the development of easily scalable synthesis methods, providing large batches of active material at competitive prices.13 A highly attractive method for the large-scale preparation of metal oxide nanoparticles appears to be flame spray pyrolysis (FSP). 26,27 We have recently reported the electrochemical characterization of the first generation of FSP-synthesi...

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