Photocatalytic behavior of silver vanadates: Microemulsion synthesis and post-reaction characterization

Abstract

h i g h l i g h t s" Silver vanadates were synthesized by microemulsion methodology not exceeding 110°C. " Silver metallic nanoparticles decorated the surface of the silver vanadates. " The photocatalytic properties were studied upon visible light. " The stability of catalysts was evaluated after reaction. " We report a synergistic effect between Ag 0 particles and silver vanadates. a r t i c l e i n f oArticle history: Available online 5 December 2012 Keywords:Silver vanadates Visible-light-driven photocatalysts Used-catalysts characterization Dye photodegradation a b s t r a c tSilver vanadates with light absorption properties in the visible region were successfully prepared by a low temperature pathway (not exceeding 110°C) using an optimized microemulsion methodology. The resulting materials were evaluated as photocatalysts in Rhodamine B photodegradation and characterized before and after reaction. The silver vanadates displayed silver metallic nanoparticles decorating the surface. The as-prepared Ag 3 VO 4 catalyst was the most active. Nevertheless, this silver vanadate suffered important changes during reaction. The initial structure evolves yielding a silver pyrovanadate, Ag 4-V 2 O 7 , with a concomitant increase of the number and size of the silver metallic nanoparticles. The synergy between these Ag 0 particles and the photoactivity of the Ag 4 V 2 O 7 phase seems responsible of the high photoactivity of this material.

Electrodeposition of Silver Vanadate Films: A Tale of Two Polymorphs

“…[1] Of these, ternary compounds generated from the two binary components, namely, Ag 2 O and V 2 O 5 , and exhibiting a range of Ag 2 O : V 2 O 5 stoichiometries (1 : 7, 1 : 2, 1 : 1, 2 : 1, 3 : 1; see Figure 1), have elicited both fundamental and practical interest (see review in Ref. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] Polymorphism in AgVO 3 has provided a platform for many studies; this compound exhibits up to four different crystallographic forms, namely, α, β, γ and δ forms. In particular, AgVO 3 has attracted considerable interest because of its wide-ranging practical applications including batteries, sensors, antibacterial formulations, and as photocatalysts for pollutant decomposition.…”

“…In particular, AgVO 3 has attracted considerable interest because of its wide-ranging practical applications including batteries, sensors, antibacterial formulations, and as photocatalysts for pollutant decomposition. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] Polymorphism in AgVO 3 has provided a platform for many studies; this compound exhibits up to four different crystallographic forms, namely, α, β, γ and δ forms. [2] The most common are the metastable α and thermodynamically-stable β polymorphs with monoclinic space groups Cm and C2/c, respectively.…”

Band offsets of novel CoTiO3/Ag3VO4 heterojunction measured by X-ray photoelectron spectroscopy

“…3a) shows two main peaks contributing to Ag 3d 5/2 and Ag 3d 3/2 . The Ag 3d 5/2 peak at 368.0 ± 0.1 eV can be deconvoluted into two components at 367.9 ± 0.1 eV and 368.5 ± 0.1 eV that correspond to Ag + and Ag 0 , respectively [2,[15][16][17]. The presence of metallic silver in this work might be due to the reduction by light of the photosensitive Ag + species during catalyst handling.…”

Nano Silver Vanadate AgVO3: Synthesis, New Functionalities and Applications

“…The microemulsion coprecipitation technique using low temperature to prepare silver vanadates was reported . Reverse micelles were formed by droplets of an aqueous solution encapsulated by a surfactant (Triton X‐100) and a co‐surfactant (1‐hexanol), dispersed in n‐heptane.…”