Ag-Vanadates/GO Nanocomposites by Aerosol-Assisted Spray Pyrolysis: Preparation and Structural and Electrochemical Characterization of a Versatile Material

Abstract

In this article, we describe the deposition by aerosol-assisted spray pyrolysis of different types of silver vanadate nanocomposites with and without graphene oxide (GO) on different substrates (carbon paper (CP) and fluorine-doped tin oxide (FTO)). When deposited on CP, different amounts of GO were added to the Ag and V precursor solution to study the effect of GO on the physicochemical properties of the resulting Ag-vanadate. It is shown that the addition of GO leads mainly to the formation of nanoparticles of the Ag2V4O11 phase, whereas Ag2V4O11 and Ag3VO4 are obtained without the addition of GO. The morphology and chemical properties of the composites were determined by scanning and transmission electron microscopies, X-ray diffraction, X-ray photoemission spectroscopy, and UV–visible and Raman spectroscopies. In addition, the photoelectrochemical (PEC) properties of such composites were studied by CV, linear sweep voltammetry, and electrochemical impedance spectroscopy. The ideal AgxVOy and GO ratio was optimized for obtaining higher photocurrent values and a good stability. The results showed that the presence of GO improves the electrical conductivity of the catalyst layer as well as the electron injection from the oxide to the electrode surface. The deposition of pure Ag2V4O11 on FTO does not lead to samples with stable PEC performances. Samples grown on CP supports showed an efficient electrochemical detection of small amounts of ethylenediamine in water solution

Electrosynthesis and Properties of Crystalline and Phase-Pure Silver Orthovanadate

“…The Raman spectra of Ag 4 V 2 O 7 characterized by one single band at about 870 cm –1 typical of tetrahedral and five-fold coordinated vanadates. Additionally, the active vibration bands at higher Raman shifts (around 900, and 950 cm –1 ) correlate well with octahedrally coordinated vanadate species. These data further confirm our conclusions from the XRD data on the phase purity of the electrodeposited α-Ag 3 VO 4 films.…”

Optimized poly(methyl methacrylate)/mixed‐phase silver vanadate nanocomposites with tuned optical properties and hydrophobicity

“…43 On the other hand, the Raman spectra exhibit two distinct modes, B 1g and B 2g , with frequencies of 794 cm À1 and 830 cm À1 , respectively. 17,18,47,48 These modes correspond to the asymmetric stretching of the distorted trigonal bipyramidal [VO 5 ] clusters and the vibration of the deformed tetrahedral [VO 4 ] cluster. 17,18,47,48 The latter is obtained from the symmetric-stretching and 5-fold coordinated vanadates.…”

Carrier Transfer and Capture Kinetics of the TiO2/Ag2V4O11 Photocatalyst

“…Ag MVV spectrum of TA2 is employed to further investigate the Ag oxidation state, as displayed in Figure 1 d. Moreover, the Auger parameter is crucial for estimating the Ag oxidation state. As is reported, the Auger parameter (α) is defined as the sum of the kinetic energy of the Auger electron (Ag M 4 VV) and the binding energy of the core level (Ag 3d5/2), and the values are about 726.1 and 724.4 eV for Ag and Ag + , respectively [ 24 , 25 ]. As for our TA2 nanoheterojunctions, the Auger parameter (α) is calculated to be 724.1eV, which is between the range of 726.1~724.4eV and approaches 724.4 eV, indicating the silver species in the TA2 are mainly Ag + and a small amount of metallic Ag.…”