Ag_2–xCu_xWO₄ Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation

Abstract

We initially reported the synthesis, characterization of structural, optical, morphological, and photocatalytic properties of Ag 1.98 Cu 0.02 WO 4 solid solution in this work. The results were compared with the same characterizations performed in pure silver tungstate. Both materials exhibited an orthorhombic structure, with a high degree of crystallinity and purity. Although, a small number of copper atoms in the orthorhombic unit cell of Ag 1.98 Cu 0.02 WO 4 were detected by changes in the X-ray diffraction peak intensity and shift in peak positions corroborates with changes observed in micro-Raman active modes. The decrease in the optical band gap, α-Ag 2 WO 4 (3.05 ± 0.03 eV) to α-Ag 1.98 Cu 0.02 WO 4 (2.93 ± 0.01 eV), determined by diffuse reflectance spectroscopy, confirms the insertion of intermediate levels between valence and conduction bands that could be associated with the Jahn−Teller effect of copper. Field-emission scanning electron microscopy images show several rod-like microcrystals for α-Ag 2 WO 4 , while there are heterogeneous microcrystals for Ag 1.98 Cu 0.02 WO 4 solid solution with an inherent polyhedral shape. The highest photocatalytic performance of α-Ag 1.98 Cu 0.02 WO 4 in the degradation of RhB molecules under visible blue light-emitting device irradiation was achieved at the end of 120 min, therefore 10.61 times faster than pure α-Ag 2 WO 4 and 37.77 times than the photolysis experiment. Through the photocatalytic experiments using the scavenger radicals, the contribution of holes (h + ), singlet oxygen ( 1 O 2 ), superoxide radicals (O 2•− ), and hydroxyl radicals ( • OH) were evaluated, where the holes (h + ), singlet oxygen ( 1 O 2 ), and superoxide radicals (O 2•− ) show the main contribution in the photocatalytic degradation of the RhB molecules to colorless organic compounds, carbon dioxide (CO 2 ), and water (H 2 O).

Mechanical Alloying in Zeolitic Imidazolate Framework for Enhanced Photocatalytic Dye Degradation

“…Recently, methylene blue (MB), a cationic dye, is one of the dangerous organic pollutants found in contaminated water because of enormous industrialization. Retrieving this dye from water by conventional methods is very difficult due to its high water solubility. , Per the literature, solid solution-based materials showed excellent performance for dye degradation compared to their parental phase , that motivated us to measure the photocatalytic degradation efficiency of MB dye by our synthesized solid solution products.…”

Solvent Effect on the Structural, Optical, Morphology, and Antimicrobial Activity of Silver Phosphate Microcrystals by Conventional Hydrothermal Method

“…To investigate the contribution of each of the photogenerated species in the degradation of the RhB solution, a study was carried out with hydroxyl radial scavengers (HO • ), superoxide radicals (O 2 •– ), electrons ( e – ), and holes ( h + ), using the SP-AC sample as a catalyst. In this case, was decided to adopt the following scavengers compounds: terbutyl alcohol (TA), parabenoquinone (PB), silver nitrate (AgNO 3 ) and ammonium oxalate (AO), respectively, as shown in Figure a . Based on these results, in the absence of the capturers, the performance of the SP-AC catalyst reached the percentage of 100% degradation of the RhB dye molecules after 20 min of visible radiation exposure.…”

“…In this case, was decided to adopt the following scavengers compounds: terbutyl alcohol (TA), parabenoquinone (PB), silver nitrate (AgNO 3 ) and ammonium oxalate (AO), respectively, as shown in Figure 7 a. 74 Based on these results, in the absence of the capturers, the performance of the SP-AC catalyst reached the percentage of 100% degradation of the RhB dye molecules after 20 min of visible radiation exposure. However, when the capturers AgNO 3 , AO, TA, and PB are adopted separately in the reaction environment, there was a reduction in photocatalytic performance by 9.17%, 28.4%, 22.3%, and 29.9%, respectively.…”

Ag2WO4 as a multifunctional material: Fundamentals and progress of an extraordinarily versatile semiconductor

“…The X-ray photoelectron spectroscopy properties of these phosphors were reported for the first time [142] The effects of solid solution formation due to the incorporation of transition-metal (TM) cations have been investigated from a combination of experimental and theoretical studies [37,143,145e149]. From a-Ag 2À2x TM x WO 4 , cations such as Ni (0 x 0.08) [119], Zn (0 x 0.25) [148] and Cu (0 x 0.12) [145,146] were used for substitution of Ag atoms. In the recently published article, Pereira et al showed that the increase in the Cu 2þ cations content in the a-Ag 2À2x Cu x WO 4 solid solutions provoked a change in the morphology to a nanoplate-like morphology formed only of (010) and ( 101) surfaces enhancing the antibacterial and antifungal activities against MRSA and C. albicans, respectively [150].…”