Photocatalytic Activity of Novel Ag₄V₂O₇ Photocatalyst Under Visible Light Irradiation

Abstract

In this study, pure Ag4V2O7 was synthesized via hydrothermal method without surfactant at different temperatures (100°C, 120°C, and 140°C) and pH values (4 and 5) for the first time. Moreover, Ag4V2O7 nanoparticles with homogeneous size distribution about 200–300 nm can be obtained by adding polyvinylpyrrolidone to the synthesis system. Effects of hydrothermal synthesis conditions on photophysical properties and photocatalytic activity of Ag4V2O7 were investigated systematically. Ag4V2O7 sample prepared at 120°C and pH = 4 had the optimal photocatalytic activity among these samples, which almost completely degraded 10 ppm Rhodamine B within 3 h under visible light irradiation (420 nm < λ < 800 nm). The degradation products were measured by liquid chromatography–mass spectroscopy. The active species involved in the degradation process were analyzed by means of adding active species scavengers, electron spin resonance techniques, and photoelectrochemical experiments. A possible mechanism for photocatalytic degradation of organic pollutants on Ag4V2O7 photocatalyst was proposed and discussed preliminarily.

One-step SDS-assisted hydrothermal synthesis and photoelectrochemical study of Ag4V2O7nanorods decorated with Ag nanoparticles

“…The photoelectrochemical experiment was carried out in a three-electrode cell with a quartz window. Ag 4 V 2 O 7 synthesized at pH = 5 was dark green in accordance with reports, 12,26 while HTS-40 sample was brownish-gray. A platinum wire and an Ag/AgCl electrode were used as the counter and reference electrodes, respectively.…”

Synthesis, surface and optical properties of Ag2CaV4O12 nanoparticles for dye removal under visible irradiation

“…The result shows that these nanoparticles could keep stable photodegradation. According to the similar reports in silver vanadates [14,15,17,18], the band structure of Ag 2 CaV 4 O 12 was displayed in Fig. 13.…”

“…For example, Ag þ ions in AgMO 3 (M: Ta and Nb) induce the valence band (VB) to be a more negative position and O 2p orbital at a more positive level, which is better for the water oxidation to get O 2 [13]. Consequently, binary vanadates containing V and Ag have been widely reported as efficient photocatalysts, which show intense optical absorptions for visible light because of the narrowed band-gap such as a/b-AgVO 3 [14], [15,16], Ag 3 VO 4 [16,17], Ag 2 Sr(VO 3 ) 4 [18], etc. In this work, Ag 2 CaV 4 O 12 was selected as a potential photocatalyst for the following motivations.…”

Disclosing the electronic structure and optical properties of Ag4V2O7crystals: experimental and theoretical insights

“…In addition, the final product is obtained with some deleterious phases, such as V 2 O 5 , amorphous AgVO 3 , Ag 3 VO 4 , and Ag 2 O, with inhomogeneous sizes and shapes. To avoid these drawbacks, several synthetic routes have recently been developed and employed in the preparation of Ag 4 V 2 O 7 micro and nanocrystals 10,24 , and pure Ag 4 V 2 O 7 crystals have been obtained through several wet chemistry-based techniques, such as conventional and surfactant-assisted hydrothermal syntheses 5,7,9,25 or microemulsions 26 . These methods circumvent the problems encountered in earlier synthetic methods and facilitate the synthesis of single phase crystals with homogeneous sizes and shapes.…”