Surfactant-Mediated Morphology and Photocatalytic Activity of α-Ag₂WO₄ Material

Abstract

In the present work, the morphology (hexagonal rod-like vs cuboid-like) of an α-Ag 2 WO 4 solid-state material is manipulated by a simple controlled-precipitation method, with and without the presence of the anionic surfactant sodium dodecyl sulfate (SDS), respectively, over short reaction times. Characterization techniques, such as X-ray diffraction analysis, Rietveld refinement analysis, Fourier-transform (FT) infrared spectroscopy, FT Raman spectroscopy, UV−vis spectroscopy, transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive X-ray spectroscopy, field emission-scanning electron microscopy (FE-SEM), and photoluminescence emission, are employed to disclose the structural and electronic properties of the α-Ag 2 WO 4 material. First-principles calculations were performed to (i) obtain the relative stability of the six low-index surfaces of α-Ag 2 WO 4 ; (ii) rationalize the crystal morphologies observed in FE-SEM images (using the Wulff construction); and (iii) determine the energy profiles associated with the transformation process between both morphologies induced by the presence of SDS. Finally, we demonstrate a relationship between morphology and photocatalytic activity, evaluated by photodegradation of Rhodamine B dye under UV light, based on the different numbers of unsaturated superficial Ag and W cations (local coordination, i.e., clusters) of each surface.

Facile Solvothermal Synthesis of Hollow BiOBr Submicrospheres with Enhanced Visible-Light-Responsive Photocatalytic Performance

“…e specific microstructures of the HBSMs are further elucidated by the following TEM characterizations. As observed in Figure 4 e clear contrast between the deeply dark edges and the pale center (Figure 4(a)) visually confirms the hollow feature of the HBSMs [37]. e shell of the HBSMs, which is composed of the nonclose stacking of ultrathin NSs, is estimated as ∼100 nm in thickness (Figure 4(b)).…”

“…Based on the above discussion, a plausible formation mechanism of the HBSMs can be tentatively proposed, as schematically illustrated in Figure 5. Generally, the surfactants are always used to mediate the morphology of materials [37][38][39]. After being dissolved in the mixed GC/IP solvent, the surfactant DDAB is self-assembled to form the special molecular structure in the mixed solvent through the hydrophobic-hydrophobic interaction.…”

Connecting structural, optical, and electronic properties and photocatalytic activity of Ag3PO4:Mo complemented by DFT calculations

“…It is important to emphasize that XPS is a surface technique. A plausible explanation is the presence of distinct compositions of pure and Mo-doped Ag3PO4 particles comparing their bulk and surface regions, which is typically observed in Ag-based complex oxides [46,47]. This phenomenon arises due to the terminations from distinct crystallographic planes that are exposed at the surface, which can be richer in [PO4] than bulk, lowering the overall Ag/P ratio at the surface.…”

The Multiple Promotion Effects of Ammonium Phosphate-Modified Ag3PO4 on Photocatalytic Performance

“…At present, although titanium dioxide is the most widely used photocatalyst, the wide band energy, and the recombination of the photogenerated electron-hole limit its application (Asahi et al, 2001;Yan et al, 2014a;Qi et al, 2016Qi et al, , 2018. Many new semiconductor materials have then developed in recent years, such as ZnO (Qi et al, 2017), CdS (Jing and Guo, 2006;Dai et al, 2018), WO 3 (Liu et al, 2019), Ag 2 WO 4 (Macedo et al, 2018), BiVO 4 (Wang et al, 2018(Wang et al, , 2019Song et al, 2019), AgCl (Han et al, 2011), C 3 N 4 (Guo et al, 2019;Huo et al, 2019;Qi et al, 2019), etc. In 2010, Yi et al (2010) reported that Ag 3 PO 4 has noticeable absorption in the UV-visible spectral range, which can utilize visible light to oxidize water to produce oxygen and degrade organic contaminants to purify water resources.…”