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[Display omitted] • Successfully designed and prepared heterojunction V o/BiVO 4 -TiO 2. • Reveal the mechanism of oxygen vacancies improving photocatalytic performance. • Elucidate the electron transfer pathways at V o/BiVO 4 -TiO 2 interfaces. Constructing heterojunction photocatalysts is a promising way to efficiently degrade organic pollutants, while its application is constrained by slow interfacial dynamics. Reported herein is an easy strategy to construct S-scheme heterojunction between BiVO 4 with oxygen vacancies (V O) and TiO 2. The V o/BiVO 4 -TiO 2 heterojunction exhibited excellent efficiency in degrading Levofloxacin (LVFX) (99.21 % degradation within 90 min) and significantly enhanced degradation kinetic (4.03 × 10-2min−1), which was 2.6 times than BiVO 4 -TiO 2 (1.53 × 10-2min−1). The mechanism lies in the fact that the introduction of V O into BiVO 4 produces impurity bands that reduce its work function, which increases the difference in Fermi energy levels of the heterojunction and, in turn, enhances the Interfacial Electric Field. Based on the experimental and theoretical simulations results, the charge transfer path at the interface of V o/BiVO 4 -TiO 2 was elucidate. This work reveals the microscopic mechanism of electric field enhancement at heterojunction interface and provides new insights for designing efficient heterojunction photocatalysts. [ABSTRACT FROM AUTHOR]

The construction of metal/semiconductor heterostructures is a useful technique for improving the electron-hole separation of Semiconductor Photocatalysts. However, there only are a few studies on the mechanism of electron transfer between metal/semiconductor heterostructures. Therefore, through the intelligent design of the material structure, two metal/semiconductor heterostructures (Au/W _18 O _49 heterostructure) were fabricated with identical composition but different structures by different preparation methods: (1) The heterostructure of Au nanoparticles at the tip of sea urchin W _18 O _49 was achieved through photoreduction method; (2) the heterostructure of Au nanoparticles at the root of sea urchin W _18 O _49 was achieved via chemical reduction method, and their electron transfer paths were studied. The results demonstrated that the two materials went through completely different electron transfer paths, and these different electron transfer path also leads to an opposite set of photocatalytic properties. The heterostructure achieved through photoreduction has the best photocatalytic performance. Nevertheless, the photocatalytic performance of the heterostructure prepared by chemical reduction is far inferior to that of the heterostructure prepared by photoreduction, and even inferior to the original W _18 O _49 sample. Therefore, we believe that the structural characteristics of metal/semiconductor heterostructure have a great influence on the electron transfer path. Our work renders useful information that may facilitate the design of heterostructure photocatalyst based on metal/semiconductors.

Despite significant advancements in the detection of cadmium (Cd(II)) based on nanomaterial adsorbability, limited research has been conducted on ultra-sensitive and selective detection mechanisms, resulting in a lack of guidance for designing efficient interface materials to detect Cd(II). Herein, reductive Fe doping on CoP facilitates an efficient Fe-Co-P electron transfer path, which renders P the electron-rich site and subsequently splits a new orbital peak that matches with that of Cd(II) for excellent electrochemical performance. The sensitivity of Cd(II) was remarkably up to 109.75 μA μM−1 on the Fe-CoP modified electrode with excellent stability and repeatability, surpassing previously reported findings. Meanwhile, the electrode exhibits exceptional selectivity towards Cd(II) ions compared to some bivalent heavy metal ions (HMIs). Moreover, X-ray absorption fine structure (XAFS) analysis reveals the interaction between P and Cd(II), which is further verified via density functional theory (DFT) calculation with the new hybrid peaks resulting from the splitting peak of P atoms coupled with the orbital energy level of Cd(II). Generally, doping engineering for specific active sites and regulation of orbital electrons not only provides valuable insights for the subsequent regulation of electronic configuration but also lays the foundation for customizing highly sensitive and selectivity sensors. [Display omitted] • The effective Fe-Co-P electron transport path is constructed by doping Fe. • The P atom adjacent to Co serves as the electron-rich center. • Splitting peak of P atomic exhibits strong orbital coupling effect with Cd(II). • The Fe-CoP achieves ultra-sensitive and selective electroanalysis towards Cd(II). • Synergies between specific active sites and orbital coupling effect are proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • High efficient TiHAP and TiFHAP films were prepared for Cr(VI) reduction. • TiHAP film has better PC and PEC activities than TiO 2 for Cr(VI) reduction. • PC and PEC activities of TiFHAP were enhanced compared to TiHAP film. • PEC reduction of Cr(VI) is mainly occurred on the surface of TiHAP photoanode. Ti-doped hydroxyapatite (TiHAP) is a novel photocatalyst with high adsorption capacity. It shows high photocatalytic activity for the degradation of organic pollutants and sterilization than conventional semiconductors. In this study, highly efficient TiHAP film and fluorine-doped TiHAP (TiFHAP) film were prepared on ITO glass by sol-gel method to investigate their photocatalytic (PC) and photoelectrocatalytic (PEC) reduction towards hexavalent chromium (Cr(VI)). Field emission scanning electronic microscope (FESEM), UV–vis spectrophotometry, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were used to characterize the morphologies, structure and composition of the samples. In the conditions of 0.5 mol/L Na 2 SO 4 , 0.5 mmol/L citric acid, 0.34 mmol/L Cr(VI) and pH = 3.4, the PC and PEC conversion rates of Cr(VI) over TiHAP film can achieve 70% and 84% under 90 min UV illumination, respectively, which were both higher than TiO 2 film. Fluorine-doped TiHAP film (TiFHAP) showed enhanced PC and PEC activities than TiHAP film, with 5.6 wt% F-doping being the best. A two-compartment system was employed to study the reaction mechanism of the PEC process. Different from the traditional knowing that Cr(VI) would be reduced on photocathode by photoinduced electrons transferred from anode photocatalyst, the result suggested that it was on the surface of TiHAP photoanode where Cr(VI) was mainly reduced. [ABSTRACT FROM AUTHOR]