Synthesis and Photocatalytic Properties of ZnWO₄ Nanocrystals via a Fast Microwave‐Assisted Method

Abstract

High crystallinity of ZnWO4 nanoparticles has been successfully synthesized via a highly effective and environmentally friendly microwave route by controlling the reaction time and temperature. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Fourier infrared spectrum (FT-IR). The crystallinity was enhanced with the increase of the reaction temperature and time. The photocatalytic activities of ZnWO4 nanocrystals were evaluated by testing the photodegradation of rhodamine B (RhB) dye under ultraviolet (UV) light irradiation. The results indicated that as-prepared ZnWO4 was highly effective for the degradation of RhB. The degradation rate of RhB reached 98.01% after 6 h of UV illumination.

Precipitation Synthesis, Characterization, Morphological Control, and Photocatalyst Application of ZnWO4 Nanoparticles

“…[18][19][20][21][22][23][24][25][26][27] There are several methods for synthesis of ZnWO 4 nanocrystals, including the solid-state method, microwave-assisted method, coprecipitation, and hydrothermal processes. 12,[28][29][30][31] Herein, we report precipitation synthesis and characterization of ZnWO 4 . Besides, several experiments were performed to investigate the effect of different solvents and polymeric surfactants such as carboxymethyl cellulose (CMC), polyethylene glycol (PEG), and polyvinyl alcohol (PVA) on the morphology, particle size, and crystal structure of the final product.…”

Eu2+ and Eu3+ Doubly Doped ZnWO4 Nanoplates with Superior Photocatalytic Performance for Dye Degradation

“…The open circles in Figure 2a represent the experimental data. As shown in Figure 2a, diffraction peaks at 14.98°, 18.86°, 23.56°, 24.36°, 38.30° and 48.36° can be assigned to the reflections from the (010), (100), (011), (110), (200), and (022) planes of monoclinic ZnWO 4 [3,27], respectively, whereas the peak at 30.40° is ascribed to the combined contributions from (111), ($\overline{1}11$),and (020) crystallographic planes as these diffractions are located too closely [2,3,6,7,10,16]. For the same reason, the four peaks located at 36.20°, 40.94°, 44.22° and 45.76° can be ascribed to the contributions from the pairs of planes (021) and (002), (121) and ($\overline{1}21$), (112) and ($\overline{1}12$), and (211) and ($\overline{2}11$), respectively.…”

“…In contrast, the Eu-doped ZnWO 4 nanoplates are not easily aggregated because of their specific architectures. As documented in the literature, Yan et al reported that the specific surface area of ZnWO 4 nanocrystals was in the range of 25–28 m 2 /g [10]; Liu et al determined the specific surface area of B-doped ZnWO 4 nanorods to be 22–47.2 m 2 /g [24]; and Su et al reported that the specific surface area was 109.4 m 2 /g for Sn 2+ -doped ZnWO 4 nanocrystals [27]. It can also be seen that the specific surface area of our Eu-doped ZnWO 4 nanoplates is much larger than the B-doped ZnWO 4 nanorods, as well as Sn 2+ -doped ZnWO 4 nanocrystals.…”

“…Belonging to a wide group of wolframite-type tungstates, zinc tungstate (ZnWO 4 ) is a technologically important material for numerous applications in the fields of luminescent materials [1,2,3,4,5], photocatalysts [6,7,8,9,10,11,12,13,14], Li-ion batteries [15], humidity sensors [16], materials for stimulated Raman scattering [17], and materials for deactivating microorganisms [18]. Among these applications, the photocatalytic properties of ZnWO 4 nanostructures have been intensively investigated in order to solve one of the most serious environmental problems in our modern society via semiconductor-based photocatalytic degradation of organic contaminants in water under sunlight [6,7,8,9,10,11].…”

“…Among these applications, the photocatalytic properties of ZnWO 4 nanostructures have been intensively investigated in order to solve one of the most serious environmental problems in our modern society via semiconductor-based photocatalytic degradation of organic contaminants in water under sunlight [6,7,8,9,10,11]. Up to date, a diverse range of strategies has been developed to enhance the photocatalytic activity of ZnWO 4 nanostructures, which can be classified into three categories: (i) synthesis of ZnWO 4 nanorods and nanosheets with large specific surface area [19]; (ii) coupling ZnWO 4 with other semiconductors and metals such as In 2 S 3 [20], Ag [21], ZnO [22], and Cu 2 O [23]; and (iii) defect engineering ZnWO 4 via doping with non-metal ions (B, C, N, F) [24,25,26], transition metal ions (Sn 2+ , Cr 3+ , Mn 2+ , Cu 2+ ) [27,28], and lanthanide ions (Dy 3+ , Er 3+ ) [29,30].…”