16 research outputs found
Density Gradient Strategy for Preparation of Broken In<sub>2</sub>O<sub>3</sub> Microtubes with Remarkably Selective Detection of Triethylamine Vapor
Tubule-like structured
metal oxides, combined with macroscale pores
onto their surfaces, can fast facilitate gas-accessible diffusion
into the sensing channels, thus leading a promoted utilization ratio
of sensing layers. However, it generally remains a challenge for developing
a reliable approach to prepare them. Herein, this contribution describes
a density gradient strategy for obtaining broken In<sub>2</sub>O<sub>3</sub> microtubes from the In<sub>2</sub>O<sub>3</sub> products
prepared using a chemical conversion method. These In<sub>2</sub>O<sub>3</sub> microtubes hold a diameter about 1.5 Ī¼m with many broken
regions and massive ultrafine nanopores onto their surfaces. When
employed as a sensing element for detection of triethylamine (TEA)
vapor, these broken In<sub>2</sub>O<sub>3</sub> microtubes exhibited
a significant response toward TEA at 1ā100 ppm and the lowest
detected concentration can reach 0.1 ppm. In addition, an excellent
selectivity of the sensor to TEA was also displayed, though upon exposure
of other interfering vapors, including ammonia, methanol, ethanol,
isopropanol, acetone, toluene, and hydrogen. Such promoted sensing
performances toward TEA were ascribed to the broken configuration
(superior gas permeability and high utilization ratio), one-dimensional
configuration with less agglomerations, and low bond energy for CāN
in a TEA molecule
Semimetallic 1Tā² WTe<sub>2</sub> Nanorods as Anode Material for the Sodium Ion Battery
Highly crystalline
semimetallic 1Tā² WTe<sub>2</sub> nanorods
(WTe<sub>2</sub> NRs) and WTe<sub>2</sub> nanoflowers (WTe<sub>2</sub> NFs) are applied as anode materials for the sodium ion battery (SIB)
for the first time. WTe<sub>2</sub> NRs and NFs are synthesized through
a novel two-step process with hydrothermal-derived WO<sub>3</sub> transformed
into WTe<sub>2</sub> NRs and NFs after a chemical vapor deposition
process. The performance of the WTe<sub>2</sub> SIB anode is highly
influenced by WTe<sub>2</sub> morphology. WTe<sub>2</sub> NRs have
shown high capacity in sodium ion storage, with an excellent rate
and cycling stability. The initial discharge capacity for WTe<sub>2</sub> NRs is 442 mA h g<sup>ā1</sup> at the current density
of 0.1 A g<sup>ā1</sup> and remains at 221 mA h g<sup>ā1</sup> after 100 cycles, while WTe<sub>2</sub> NFs show 324 mA h g<sup>ā1</sup> initial capacity and remain at 260 mA h g<sup>ā1</sup> after 40 cycles. The Coulombic efficiencies of both WTe<sub>2</sub> NR and NF anodes are as high as 98.83 and 97.96% from the second
cycle, respectively
Steam channeling control in the steam flooding of super heavy oil reservoirs, Shengli Oilfield
Electroassisted Fabrication of Free-Standing Silica Structures of Micrometer Size
Free-standing porous silica microstructures have been
made via
the electroassisted deposition of silica in an appropriately patterned
array of recessed electrodes consisting of hydrophilic and hydrophobic
domains. The 100 nm deep recessed indium tin oxide (ITO) electrodes
were prepared by a photolithographic/chemical etching process on Glass/ITO/Au
substrates. Hydrophobic areas were formed by passivation of unetched
gold with a self-assembled monolayer of 1-octadecanethiol. Application
of sufficiently negative potentials produced thick layers of silica
that extended across the whole substrate; however, because of adhesion
differences of silica on hydrophilic (ITO) and hydrophobic (thiol-modified
gold) surfaces, selective removal of silica from the more hydrophobic
areas of the substrate was achieved. The surface morphology, porosity,
and thickness of resultant microstructures depended on the concentration
of tetramethoxysilane in the sol, the electrolysis time, and the applied
potential, all of which have been varied. Free-standing silica features
of different geometries including bands, squares, and circles, ranging
in width from 60 to 500 Ī¼m and heights >1 Ī¼m, have
been
prepared using this approach. Scanning electron microscopy (SEM) images
showed the materials to consist of aggregates of colloidal particles
that extend tens to thousands of nanometers above the surface. Such
film-like materials have important characteristics that make them
ideally suited as a platform for chemical sensors; most notably, an
open framework and the presence of interconnected pores within individual
microstructures
Nitrogen and Sulfur Co-Doped Hierarchically Porous Carbon Nanotubes for Fast Potassium Ion Storage
Exploration of advanced carbon anode material is the key to circumventing the sluggish kinetics and poor rate capability for potassium ion storage. Herein, a synergistic synthetic strategy of engineering both surface and structure is adopted to design N, S co-doped carbon nanotubes (NS-CNTs). The as-designed NS-CNTs exhibit unique features of defective carbon surface, hollow tubular channel, and enlarged interlayer space. These features significantly contribute to a large potassium storage capacity of 307Ā mA h gā1 at 1 A gā1 and a remarkable rate performance with a capacity of 151Ā mA h gā1 even at 5 A gā1. Furthermore, an excellent cyclability with 98% capacity retention after 500 cycles at 2 A gā1 is also achieved. Systematic analysis by in situ Raman spectroscopy and ex situ TEM demonstrates the structural stability and reversibility in the chargeādischarge process. Although the kinetics studies reveal the capacitive-dominated process for potassium storage, density functional theory calculations provide evidence that N, S co-doping contributes to expanding the interlayer space to promote the K-ion insertion, improving the electronic conductivity, and providing ample defective sites to favor the K-ion adsorption.</p
Enhancing Sodium-Ion Storage Behaviors in TiNb<sub>2</sub>O<sub>7</sub> by Mechanical Ball Milling
Sodium-ion batteries
(SIBs) have shown extensive prospects as alternative rechargeable
batteries in large-scale energy storage systems, because of the abundance
and low cost of sodium. The development of high-performance cathode
and anode materials is a big challenge for SIBs. As is well known,
TiNb<sub>2</sub>O<sub>7</sub> (TNO) exhibits a high capacity of ā¼250
mAh g<sup>ā1</sup> with excellent capacity retention as a Li-insertion
anode for lithium-ion batteries, but it has rarely been discussed
as an anode for SIBs. Here, we demonstrate ball-milled TiNb<sub>2</sub>O<sub>7</sub> (BM-TNO) as an SIB anode, which provides an average
voltage of ā¼0.6 V and a reversible capacity of ā¼180
mAh g<sup>ā1</sup> at a current density of 15 mA g<sup>ā1</sup>, and presents excellent cyclability with 95% capacity retention
after 500 cycles at 500 mA g<sup>ā1</sup>. A possible Na storage
mechanism in BM-TNO is also proposed