Dual Functional Ta-Doped Electrospun TiO₂ Nanofibers with Enhanced Photocatalysis and SERS Detection for Organic Compounds

Abstract

There is a growing interest in multifunctional nanomaterials for the detection as well as degradation of organic contaminants in the water. In this work, we report on the development of dual functional TiO nanofibers (TNF) with different tantalum (Ta) doping (1-10 mol %) by a simple electrospinning technique. As-prepared TNF show mesoporous dominant structure, which are favorable for photocatalytic activity due to the presence of catalytic spots. Ta doping decreases the crystalline size within TiO matrix because of the incorporation of Ta ions and restricts the phase transformation from anatase to rutile. Ta doping slightly enhances the visible light absorption because of the Ti defects sites created upon Ta doping. The effect of Ta doping within TiO matrix was systematically studied for the degradation of methylene blue (MB) dye under ultraviolet (UV) and solar light irradiation. The 5% Ta-doped TNF were found to be optimal and showed 5.1 and 2.2 times higher photocatalytic activity as compared to TNF under UV and solar light irradiation, respectively. The effect of Ta doping for the detection of MB molecules was also studied by surface enhanced Raman scattering (SERS). It was observed that 5% Ta-doped TNF exhibit higher photocatalytic activity and enhanced SERS signals of adsorbed MB molecules as compared to the TNF. The enhanced photocatalytic and SERS activities can be explained as combined effects of enhanced visible light absorption, lower crystalline size, and slightly higher surface area. The observed results show that Ta doping induces new energy levels below the conduction band of TiO because of Ti defects, which inhibit the photogenerated charge recombination acting as electron traps and promote charge transfer mechanism acting as an intermediate state for TiO to MB molecule electron transfer, and are mainly responsible for the enhanced photocatalytic and SERS activities, respectively.

Nanofibers for Water and Wastewater Treatment: Recent Advances and Developments

“…PVP (or PVA) is generally used as a temporary carrier in the electrospinning process and is burned off after the membranes are formed. Various materials, such as MoS 2 , TiO 2 , and SiO 2 , can be made into inorganic nanofiber membranes (Ren et al 2018;Singh et al 2017;Yang et al 2017;Wang et al 2017c). To improve the degradation efficiency, additional particles (CoFe 2 O 4 , Pt, and MnO 2 ) were incorporated to impart hierarchical structure to the membrane surface.…”

A magnetic γ-Fe2O3@PANI@TiO2 core–shell nanocomposite for arsenic removal via a coupled visible-light-induced photocatalytic oxidation–adsorption process

“…[14][15][16] Among them, the UV/TiO 2 system distinguishes itself by its stability and low cost. [17][18][19][20][21] However, TiO 2 delivers only a limited adsorption capacity, resulting in an inefficient removal capacity. 22,23 Therefore, development of systems for efficient oxidation of As(III) to As(V) and simultaneous removal of As(V) has received increasing attention.…”

Influence of Re and Ru doping on the structural, optical and photocatalytic properties of nanocrystalline TiO2

“…Therefore, much effort has been expended to reduce the recombination rate of TiO 2 and to enhance its photocatalytic efficiency under both UV and visible light irradiation. Several approaches have been undertaken, including doping with non-metals such N, C and S [33][34][35][36], transition metals (TM) including Fe, Co, Cr, Cu, Mo and Ta [37][38][39][40][41][42][43] or rare earth metals such as Ce, La, Eu and Ga [44][45][46][47][48][49], inducing structural defects such as Ti 3+ or oxygen vacancies [50][51][52], and coupling TiO 2 with noble metals [14,53,54], narrow bandgap semiconductors [55,56], hydroxyapatite [57] or graphene [54] giving rise to TiO 2 -based hybrid structures with improved properties. Among the different approaches, the incorporation of dopants in low concentrations into the TiO 2 lattice have been shown to be a simple an effective way to reduce the electron-hole recombination rate and enhance absorption in the visible region of the electromagnetic spectrum.…”