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[Display omitted] • Urchin-like TiO 2 /Ti 3 C 2 O x (MXene) photocatalysts have been successfully fabricated. • Surface -O terminated Ti 3 C 2 O x has a work function about 0.3 eV higher than that of TiO 2. • The photocatalytic H 2 evolution and LEV degradation of TiO 2 /Ti 3 C 2 O x are 9.7 and 6.7 folds higher than those of TiO 2 , respectively. • The photocatalytic reaction pathways were carefully investigated. • The photogenerated carriers were efficiently separated at the TiO 2 /Ti 3 C 2 O x interface. The surface groups of MXene act as a decisive role on the performance of MXene-based photocatalysts. In this work, TiO 2 nano-whiskers were grown in-situ on Ti 3 C 2 T x , through a hydrothermal and post-heat treatment process, meanwhile, the surface groups of Ti 3 C 2 T x were unified -O adsorption. The as-prepared urchin-like TiO 2 /Ti 3 C 2 O x composite have efficient activity for photocatalytic hydrogen evolution and degradation of levofloxacin (LEV). The optimized hydrogen evolution reaction (HER) performance reached 346.8 μmol g-1 h−1, and the apparent quantum yield at 313 nm was 7.67%. Its hydrogen production performance and degradation rate of LEV were 9.7 and 7.7 folds higher than those of pure TiO 2 , respectively. The -O terminated Ti 3 C 2 O x achieving a work function about 0.3 eV larger than TiO 2 , as both DFT calculation and UPS measurement depicted. Therefore, the photogenerated e-/h+ were separated at the TiO 2 /Ti 3 C 2 O x interface via Schottky junction, a large amount of e- was enriched on Ti 3 C 2 O x , which enabled the photocatalyst with remarkable charge separation and photocatalytic performance. Meanwhile, the reaction pathways of TiO 2 /Ti 3 C 2 O x photocatalytic HER and LEV degradation/mineralization were carefully investigated. This study underlines the significance of surface groups on photocatalysts composed of MXenes, and sheds light on the new approach to the rational design of high-efficiency MXene-based photocatalysts. [ABSTRACT FROM AUTHOR]

A novel type of Bi/PMo 12 doped TiO 2 composite was successfully constructed through a simple electrospinning/calcination technology and hydrothermal method. These materials demonstrated outstanding and durable visible-light catalytic ability for pollutants degradation (TC, EFA and MO), which resulted from the PMo 12 doping, SPR effect of Bi NPs and the Schottky junction between Bi NPs and PMo 12 doped TiO 2. The influence factors (dosage of catalyst, concentration of TC, the pH of solution, reaction temperature, inorganic anions, water quality) on TC degradation were comprehensively investigated. The possible TC degradation pathways were established based on the identification of degradation products by HPLC-MS. The toxicity of intermediates was also assessed through QSAR prediction. [Display omitted] • Bi/PMo 12 doped TiO 2 was prepared via electrospinning and hydrothermal methods. • They showed good visible-light degrade activity for various pollutants. • The effect of operating parameters on TC degradation was detailedly studied. • The possible degradation pathways of TC were investigated by HPLC-MS. • The toxicity of TC degradation intermediates was assessed by QSAR prediction. Exploration of visible-light-responsive, efficient and durable photocatalysts is of great concern for removing organic dyes and antibiotics from the wastewater. Herein, a series of mesoporous TiO 2 -doped with polyoxometalates [H 3 PMo 12 O 40 ] (PMo 12) and loaded with Bi nanoparticles (NPs) composites were fabricated through a convenient electrospinning/calcination and hydrothermal methods, which was labelled as × wt% Bi/PMo 12 doped TiO 2 (abbr. x % Bi/PT, x = 10, 20 and 30, respectively). In these composites, polyoxometalate PMo 12 acts as a dopant to reduce the band gap value of TiO 2 , effectively expanding its visible light absorption and enhance its photocatalytic redox ability. Moreover, the Schottky junction between Bi NPs and PT further promotes the separation efficiency of the photoinduced carriers. Therefore, these as-prepared catalysts demonstrated outstanding and persistent photocatalytic activity for removing tetracycline (TC), enrofloxacin (EFA) and methyl orange (MO) with visible-light (λ > 420 nm) illumination. Especially, 20 % Bi/PT specimen presented the optimal catalytic performance, whose degradation efficiencies for TC, EFA and MO reached 86.0 %, 90.9 % and 92.5 % with k = 0.03019, 0.01275 and 0.01199 min−1, respectively. The superoxide radical (⋅O 2 –), hydroxyl radical (⋅OH) and holes (h+) were proved to be the dominating active species in contaminants degradation through the trapping tests and electron spin resonance (ESR) measurements. Furthermore, the possible TC degradation pathways were established based on the identification of degradation products by high performance liquid chromatography-mass spectrometry (HPLC-MS). The toxicity of intermediates was also assessed through QSAR prediction. According to the energy band structure analysis, the corresponding photocatalytic mechanism was revealed. The current work provides several new insights for the design and preparation of low cost, efficient, stable and versatile photocatalysts. [ABSTRACT FROM AUTHOR]