Rapid Synthesis of Thin and Long Mo17O47 Nanowire-Arrays in an Oxygen Deficient Flame

Abstract

Mo17O47 nanowire-arrays are promising active materials and electrically-conductive supports for batteries and other devices. While high surface area resulting from long, thin, densely packed nanowires generally leads to improved performance in a wide variety of applications, the Mo17O47 nanowire-arrays synthesized previously by electrically-heated chemical vapor deposition under vacuum conditions were relatively thick and short. Here, we demonstrate a method to grow significantly thinner and longer, densely packed, high-purity Mo17O47 nanowire-arrays with diameters of 20–60 nm and lengths of 4–6 μm on metal foil substrates using rapid atmospheric flame vapor deposition without any chamber or walls. The atmospheric pressure and 1000 °C evaporation temperature resulted in smaller diameters, longer lengths and order-of-magnitude faster growth rate than previously demonstrated. As explained by kinetic and thermodynamic calculations, the selective synthesis of high-purity Mo17O47 nanowires is achieved due to low oxygen partial pressure in the flame products as a result of the high ratio of fuel to oxidizer supplied to the flame, which enables the correct ratio of MoO2 and MoO3 vapor concentrations for the growth of Mo17O47. This flame synthesis method is therefore a promising route for the growth of composition-controlled one-dimensional metal oxide nanomaterials for many applications.

Ultrahigh-Quality Infrared Polaritonic Resonators Based on Bottom-Up-Synthesized van der Waals Nanoribbons

“…The synthesis of α-MoO 3 under fuel-lean flame conditions yields thermodynamically favorable conditions for crystalline, stoichiometric materials growth (see Methods). The composition of the as-grown material is confirmed to be MoO 3 with negligible oxygen deficiency using X-ray photoelectron spectroscopy, and the high degree of crystallinity is confirmed with X-ray diffraction (Supporting Information). We also probe the crystallinity and phase of as-grown MoO 3 structures using high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), which confirm that the structures are crystalline orthorhombic α-MoO 3 , the preferred growth direction is [001], and the out-of-plane orientation is [010] (Figure b).…”

Rapid Flame Synthesis of Atomically Thin MoO3 down to Monolayer Thickness for Effective Hole Doping of WSe2

“…Flame synthesis has demonstrated the advantages of rapid growth rate, low cost, and great scalability. − It has been widely employed in industry for manufacturing of many commodity zero-dimensional (0D) nanoparticles, such as carbon black, titanium dioxide, and silicon dioxide, and their annual production volume is millions of tons with market value at over $15 billion . In recent years, flame synthesis has also been successfully applied to the growth of one-dimensional (1D) metal oxide nanowires, including tungsten oxides, , molybdenum oxide, , iron oxides, copper oxide, and zinc oxide. , Despite the success in flame synthesis of 0D and 1D metal oxides, flame synthesis of 2D metal oxides has not been explored yet.…”

Morphology‐Dependent Catalytic Performance of MoS2/MoOx Heterojunction Nanostructures for Hydrogen Evolution Reaction

“…The XRD spectra of both MoO 3 morphologies are well matched to the orthorhombic MoO 3 structures . Some peaks deviated from standard MoO 3 are relevant to insufficient MoO 3− x data such as Mo 4 O 11 . This might be due to imperfect substitution reaction during annealing procedure and oxidation in the air exposure.…”