Semiconductor-based gas sensors that use n-type WO3 or p-type Co3O4 powder were fabricated and their gas sensing properties toward NO2 or NO (0.5-5 ppm in air) were investigated at 100 °C or 200 °C. The resistance of the WO3-based sensor increased on exposure to NO2 and NO. On the other hand, the resistance of the Co3O4-based sensor varied depending on the operating temperature and the gas spec...

Ultrafine WO3 nanoparticles were synthesized by nanocasting route, using mesoporous SiO2 as a template. BET measurements showed a specific surface area of 700 m 2/gr for synthesized SiO2, while after impregnation and template removal, this area was reduced to 43 m 2/gr for WO3 nanoparticles. HRTEM results showed single crystalline nanoparticles with average particle size of about 5 nm possessin...

We measured valence band offsets in Ta2O5–WO3, Ta2O5–Nb2O5 and WO3–Nb2O5 heterostructure couples by in situ x-ray photoelectron spectroscopy, immediately following the bi-layer growth in ultra-high vacuum. Conduction band offsets were estimated using the measured valence band offsets in conjunction with the literature values for the respective band gaps. The offsets between Ta2O5 and WO3 and be...

Thin amorphous films of tungsten oxide (WO3) are well known to change their optical absorption behavior upon light exposure, usually referred to as photochromic effect. Since the formation of color centers is closely related to the optical creation of electron-hole pairs the sensitivity of the photochromic effect in WO3 is limited to energies above its band-gap energy of 3.25 eV, corresponding ...

A self-biasing photoelectrochemical (PEC) cell that could work for spontaneous overall water splitting in a neutral solution was established based on the mismatched Fermi levels between the photoelectrodes. A Pt-catalyst-decorated crystalline silicon photovoltaic cell (Pt/PVC) was prepared and employed as an effective photocathode. This was coupled with a poly(ethylene glycol)-directed WO3/W ph...

This study assessed 3D WO3–TiO2 nanoflowers (WTNF) synthesized by a combined hydrothermal–ultrasonication–impregnation method for their applicability to the treatment of aromatic volatile compounds under visible-light illumination. The scanning electron microscopy exhibited the formation of 3D structures in the prepared WTNF samples. The X-ray diffraction patterns and energy dispersive X-ray re...

In this study, Pt-M/WO3 (M = Cu, Co, and Ni) thin films are effectively synthesized by preparing homogeneous precursor sols, spin-coating, toluene-etching, calcination. Furthermore, the microstructural, chemical, electrochemical properties of WO3, Pt-Cu/WO3, Pt-Co/WO3, Pt-Ni/WO3 also systematically compared. The results demonstrate that when compared to WO3 film, photocatalytic capability for m...

Mixtures of WO3 and Cr2O3 in varying weight ratios as well as adjacent alignment of these two powders were both examined as possible designs for NO-selective sensor. Studies focused on resistance measurements toward NO and CO at 300 ◦C were carried out. Using the sensor design with the adjacent alignment of n-type WO3 and p-type Cr2O3 resulted in optimal performance. This sensor design exploits...

In the present study, the possibility of concentrating tungsten-copper vein ore in South Chah-Palang was examined using gravity separators including Jig Machine (-2360+600 μm), shaking table (-600+120 μm), and multi-gravity separator (MGS) (-120 μm). The representative sample contains 1.5% WO3 and 5.95% CuO. The main tungsten minerals were ferberite and wolframite and their appropriate liberati...

We analyze mesoscale light absorption and carrier collection in a tandem junction photoelectrochemical device using electromagnetic simulations. The tandem device consists of silicon (E(g,Si) = 1.1 eV) and tungsten oxide (E(g,WO3) = 2.6 eV) as photocathode and photoanode materials, respectively. Specifically, we investigated Si microwires with lengths of 100 µm, and diameters of 2 µm, with a 7 ...