Oxide vacancies enhanced visible active photocatalytic W₁₉O₅₅NMRs via strong adsorption

Abstract

W 19 O 55 nano-/micron-rods (NMRs) were synthesized through calcining WO 3 powders under a reducing atmosphere with S vapor in a vacuum furnace. For comparison, the as-prepared W 19 O 55 NMRs were then annealed at 500 C for 2 h to obtain WO 3 NMRs. The decolourization of organic dyes methylene blue and rhodamine B under visible light by the two kinds of NMRs reveals that the oxygen-deficient W 19 O 55 sample will present better comprehensive performance due to its stronger surface adsorption to the dye molecules, which could be attributed to the oxygen vacancies.

Role of Oxygen Vacancies in the Electrical Properties of WO3−x Nano/Microrods with Identical Morphology

“…It is seen that the Nyquist plots of the as-synthesized WO 3 and WO 2.90 both present a complete semicircle, while those of W 19 O 55 and W 18 O 49 only show a trend for a semicircle, possibly because, with increasing , the semiconductivity of WO 3−x decreased and the metallicity increased. But with the increase of oxygen vacancies, the arc radius of the EIS Nyquist plots presents a sharp decrease, indicating a decrease in the solid state interface layer resistance and the charge transfer resistance on the surface [3]. This result also suggests that, with the increase of oxygen vacancies, the charge carriers transfer efficiency of WO 3−x increased.…”

“…Similarly with WO 3 devices, it can be clearly seen that a semicircle was observed in the complex impedance plots at low relative humidity (11-33%). But at high relative humidity (54-95%), it is quite clear that the straight line appeared at low frequency would present at a higher relative humidity than that of WO 3 , due to the fact that the content of oxygen vacancy in WO 2.90 is much higher than that in WO 3 With increasing relative humidity, a large amount of water molecules would be absorbed by oxygen vacancies, which will result in a continuous electrolytic film. Then the electron conduction becomes less dominant, while the contribution of electrolytic conduction will increase.…”

“…Among the various forms of tungsten materials, tungsten oxides are important semiconductors, which can be used in solar-driven photocatalysis [1][2][3], electrochromism [4], and photochromism [5]. In addition, tungsten oxides are highly sensitive to many kinds of gas, which are considered as one of the most promising gas sensing materials for the detection of NH 3 , H 2 S, NO x , O 3 , H 2 , and so on [6][7][8][9].…”

Synthesis of WOn‐WX2 (n=2.7, 2.9; X=S, Se) Heterostructures for Highly Efficient Green Quantum Dot Light‐Emitting Diodes

“…Interestingly,the STEM image shows that the single-layer WS 2 has two different crystal phases, [18] that is,2 H-WS 2 ( Figure S3a (Figure 1c), which are similar with the previously reported results. [17] Moreover,t he composition of heterostructures and the coexistence of 2H and 1T' phases in WS 2 NSs were confirmed by XPS.A ss hown in Figure 1e,t he high-resolution XPS W4fs pectrum of WO 2.9 NP-WS 2 NS heterostructures can be fitted to six peaks,which are corresponding to the binding energies of WO 2.9 (35.31 and 37.58 eV), [16] 2H-phase WS 2 (32.65 and 34.26 eV) [17] and 1T'-phase WS 2 (31.88 and 33.44 eV), [17] respectively.…”

“…TheT EM and HRTEM images show that WO 2.9 NPs with size of 3.0 AE 0.4 nm were obtained ( Figure S13a, b). [16] After the addition of sulfur, the products collected at different reaction time,t hat is, from 30 min to 3h,w ere characterized. [16] After the addition of sulfur, the products collected at different reaction time,t hat is, from 30 min to 3h,w ere characterized.…”