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In2S3/BiOI composites were synthesized at room temperature which significantly improved the photocatalytic degradation of tetracycline hydrochloride (TC) under visible light irradiation. Structure and morphology characterization techniques have been performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction measurements (XRD) and X-ray photoelectron spectra (XPS). The separation ability of photogenerated carriers is enhanced due to the formation of heterojunctions of the composites. The best performance is obtained when the content of In2S3 is 7 wt%. Compared with In2S3 and BiOI alone, 7-In2S3/BiOI has the highest specific surface area and can provide more active sites. Based on the photo-electrochemical characterization and free radical tests, a photocatalytic mechanism of In2S3/BiOI composites in the presence of superoxide radicals (˙O2−) and holes (h+) is reasonably proposed. [ABSTRACT FROM AUTHOR]

Investigation of the mechanism of oxygen vacancy-regulated photoelectrochemical sensors for highly sensitive and selective determination of biomolecules containing electron-donating groups is an innovative research field. In this study, oxygen vacancy-regulated TiO 2 nanotube arrays (Ov-TNTs) with high photoelectrochemical activity were synthesized and applied to defect tetracycline hydrochloride (TC). The synergistic effect of oxygen vacancies and Ti3+ droves Ov-TNTs with a narrow energy band to generate more photogenerated carriers under irradiation. The photocurrent response of the oxygen vacancy-regulated photoelectrochemical sensor decreased with increasing TC concentration, which could be mainly attributed to adsorption of TC, which consumed part of the oxygen vacancies on the surface of Ov-TNTs. This system had excellent linearity in the range of 0.1–1000 nM with a detection limit of 0.33 nM (S/N = 3). In addition, the sensor was highly selective for TC determination due to the mutual electrostatic interaction between negatively charged TC-containing electron-donating groups (-NH 2 and -OH) and positively charged Ov-TNTs. This study provided a foundation for developing an oxygen vacancy-regulated adsorptive photoelectrochemical sensor. • The introduction of oxygen vacancies drives TNTs with narrow energy band to generate more photogenerated carriers. • Oxygen vacancies can be used as electron traps for preferential adsorption of TC molecules with electron-donating groups. • The photoelectrochemical sensor exhibits superior sensitivity and selectivity for TC detection. • The mechanism investigation shows that the adsorption of TC on the surface of Ov-TNTs decreases the oxygen vacancies and Ti3 + concentration, resulting in the gradual recovery of photocurrent to pure TNTs. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have attracted great interest in the field of photocatalysis because of their adjustable porous structure and semiconductor properties. In this research, a new type of MIL-88B(Fe)/Bi 2 WO 6 was successfully prepared by growing MIL-88B(Fe) on the surface of flower-like Bi 2 WO 6 spheres. The structures of materials were characterized through XRD, BET, XPS, SEM, TEM, EDX and FT-IR. 7-MIL-88B(Fe)/Bi 2 WO 6 exhibits the highest photocatalytic performance with a degradation rate of 96.4% within 90 min under visible light irradiation. Compared with pure Bi 2 WO 6 or MIL-88B(Fe), 7-MIL-88B(Fe)/Bi 2 WO 6 exhibits the largest specific surface area to provide more active sites. Additionally, the ·O 2 - and ·OH played dominant roles during the photocatalytic degradation process based on trapping and ESR tests. Through cyclic experiments, MIL-88B(Fe)/Bi 2 WO 6 composites show good stability and degradation efficiency, indicating its application potential in the environmental field. [Display omitted] [ABSTRACT FROM AUTHOR]