In-Situ Fabricating V2O5/TiO2-Carbon Heterojunction from Ti3C2 MXene as Highly Active Visible-Light Photocatalyst

Abstract

Titanium dioxide is a mainstream photocatalyst, but it still confronts great obstacles of poor visible light absorption and rapid recombination rate of photogenerated carriers. Herein, we describe the design of a highly active visible-light photocatalytic system of graphited carbon layers anchored V2O5/TiO2 heterojunctions derived from Ti3C2 MXene, which demonstrates about 4.58 and 2.79 times higher degradation activity of MB under visible light (λ > 420 nm) than pure V2O5 and TiO2-carbon. Combined with the characterization results, the formed V2O5/TiO2 heterojunction promotes the separation of photogenerated carriers, while the graphitized carbon derived from MXene acts as an electronic reservoir to enhance the absorption of visible light. The ESR results show that superoxide radicals and hydroxyl radicals are the main active species in the reaction system. Therefore, we propose a possible mechanism model to provide a feasible idea for the subsequent design of high-efficiency photocatalysts for environmental treatment.

Preparation, Microstructural Characterization and Photocatalysis Tests of V5+-Doped TiO2/WO3 Nanocomposites Supported on Electrospun Membranes

“…The light source must have a higher energy than the material bandgap energy, so that electrons from its valence band can be ejected into its conduction band, which would not occur using visible light. Advances in this field of research involve the incorporation of selective metal oxides into TiO 2 , such as tungsten, zinc, indium, copper, niobium, and vanadium oxides, in order to increase the process efficiency [1,15,17,18].…”

“…Tungsten trioxide (WO 3 , 2.6-2.8 eV bandgap) has excellent electrical charge transfer properties, broadens the excitation wavelength range of the final material, in addition to promoting effective photocharge separation of the composite catalyst and inhibiting electron-hole recombination, which significantly improves the MON photocatalytic activity [19,20]. The interaction of WO 3 with TiO 2 increases the conductivity of the TiO 2 /WO 3 system in comparison to pure TiO 2 [21,22], while TiO 2 doping with niobium pentoxide (Nb 2 O 5 ) [23] or vanadium pentoxide (V 2 O 5 ) [24] delays the phase transition from anatase to rutile (phase with less active surface) and improves the electronic properties of the resulting material [17]. In addition, the combined action between TiO 2 , WO 3 , and V 2 O 5 results in nanocomposites with superior performance (sensitivity, electric and electronic properties, catalysis and phase stability), which demonstrate the emerging possibilities of using this MON configuration for environmental decontamination applications [21,25,26].…”