Synthesis, characterization, and photocatalytic activity of a novel Si2O3/Ag3VO4 heterojunction photocatalyst

In this investigation, the single-step hydrothermal method is used to synthesize novel Bi2O3/Ag3VO4 heterojunction photocatalysts (BAVs). BAVs were generated under different Bi2O3/Ag(3)VO(4 )molar ratios and their photocatalytic activity was evaluated by using them to degrade C.I. Reactive Red 2 (RR2) under ultraviolet (UV), visible-light (Vis.) or solar irradiation. The morphological, structural, and spectroscopic properties of the prepared samples were determined using X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), specific surface area analysis, UV-Vis. diffuse reflectance spectral analysis, photoluminescence spectral analysis, and X-ray photoelectron spectroscopy (XPS). Surface analyses by XRD, TEM, and XPS revealed that the interaction between Ag3VO4 and Bi2O3 involved chemical bonding rather than simple physical mixing. The BET surface areas of Ag3VO4, Bi2O3, and 1BAV were 0.18, 0.94, and 1.11 m(2)/g, respectively. The photodegradation of RR2 was consistent with the pseudo-first-order model and the optimal Bi2O3/Ag3VO4 molar ratio was unity (1BAV). The rate constants of RR2 photodegradation by Ag3VO4, Bi2O3, and 1BAV under Vis. irradiation were 0.048, 1.50, and 3.16 h(-1), respectively. The enhanced photocatalytic performance of 1BAV was attributed to the reduced recombination probability of the photo-generated electrons and holes. Coupling Ag3VO4 with Bi2O3 could reduce the leaching of Ag from Ag3VO4 during photodegradation. The experimental results indicate that photo-generated holes and superoxide anion radicals were the predominant active species in 1BAV.