Microwave synthesis, photoluminescence, and photocatalytic activity of PVA-functionalized Eu3+-doped BiOX (X = Cl, Br, I) nanoflakes.
We report a facile microwave-assisted green synthetic route for colloidal poly(vinyl alcohol) (PVA)-coated europium (Eu(3+))-doped luminescent heavy metal bismuth oxyhalide (BiOX; X = Cl, Br, I) nanoflakes at low temperature and examine their structural, optical, and photocatalytic characteristics. PVA coating onto the surface of the nanoflakes endows them with hydrophilic nature. Both Eu(3+)-doped BiOCl and BiOBr nanoflakes exhibit strong optical properties related to Eu(3+) and Bi(3+) which are quenched in case of Eu(3+)-doped BiOI matrix. These results are supported by Eu(3+) photoluminescence lifetime values of 0.61 ms, 0.59 ms, and 8.9 μs, respectively. The former two matrices have quite similar crystal field environments as deduced from the asymmetric ratios of (5)D0 → (7)F2 (614 nm) and (5)D0 → (7)F1 (591 nm) transitions. In addition to possessing interesting photoluminescence properties, a comparison of the photocatalytic activity of Eu(3+)-doped BiOX (X = Cl, Br, I) nanoflakes, with corresponding estimated band gaps of 3.36, 2.74, and 1.67 eV has been evaluated using Rhodamine B (RhB) dye under visible light irradiation. The nanoflakes exhibited 100% dye degradation under visible light irradiation. Eu(3+)-doped BiOCl nanoflakes manifested higher photocatalytic efficiency compared to the other matrices following apparent first-order kinetics. Such a boost in efficiency is attributed to their high surface area to volume ratios, layered crystalline structures, indirect band gap nature, and ability to utilize broad bands in the solar spectrum.
Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER)-Kolkata , Mohanpur Campus, Nadia district, Mohanpur, West Bengal 741252, India.
Armita
A
Dash
Shyam
S
Sarkar
Venkata N K B
VN
Adusumalli
Venkataramanan
V
Mahalingam