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Photocatalysis is considered as an effective technique for mitigating ecological risks posed by residual tetracycline (TC). To improve the efficiency of this technique, it is necessary to enable photocatalysts to produce highly reactive species, such as singlet oxygen (1O2). However, due to the high activation energy of 1O2, photocatalysts can hardly produce 1O2 without assistance from external oxidants. Herein, we find that the size-reduced α-Fe2O3 nanoparticles (∼ 4 nm) that anchored on g-C3N4 nanotube (α-Fe2O3@CNNT) can spontaneously generate 1O2 for degradation of TC. In comparison, only hydroxyl radical (·OH) can be produced by g-C3N4 nanotube loaded with ∼ 14 nm α-Fe2O3 nanoparticles (α-Fe2O3/CNNT). Owing to the high reactivity of the 1O2 species, the photocatalytic degradation rate (Kapp) of TC with α-Fe2O3@CNNT (0.056 min−1) was 1.8 times higher than that of α-Fe2O3/CNNT. The experimental results and theoretical calculations suggested that reducing the size of α-Fe2O3 nanoparticles anchored on g-C3N4 nanotube decreased the surface electron density of α-Fe2O3, which induces the generation of high-valent Fe(IV) active sites over α-Fe2O3@CNNT and turns the degradation pathway into a unique 1O2 dominated process. This study provides a new insight on the generation of 1O2 for effective degradation of environmental pollutant. [ABSTRACT FROM AUTHOR]

This work has prepared a series of CuO/g-C 3 N 4 nanocomposites with CuO nanospindles anchoring on g-C 3 N 4 nanosheets by facile ultrasonic treatment and impregnation method. The optimum 15%CuO/g-C 3 N 4 sample exhibited higher efficiency, about 9 times and 20 times than pure g-C 3 N 4 for photocatalytic degradation of Rhodamine B (RhB) and CO 2 reduction respectively. Morphology of CuO and composition of CuO/g-C 3 N 4 photocatalysts were fully characterized. The excellent performance of CuO/g-C 3 N 4 nanocomposites is mainly attributed to novel morphology and its pivotal effect on light absorption, dynamics of charge carriers, and regulated band structure. We put forward a new combination method of CuO nanospindles with g-C 3 N 4 nanosheets by simple and green preparation, which may pave the way for the synthesis of CuO/g-C 3 N 4 heterojunctions and its photocatalysis application both in environment and energy. [Display omitted] • CuO/g-C 3 N 4 photocatalyst was prepared by ultrasonic treatment and impregnation method. • Special CuO nanospindles were successfully anchored on g-C 3 N 4 nanosheets. • Photocatalytic activity in both pollutant degradation and CO 2 reduction was improved. • Construction of efficient heterojunction between CuO and g-C 3 N 4 is matter to activity. [ABSTRACT FROM AUTHOR]

A novel N H TiO 2 photocatalyst was prepared via hydrothermal synthesis followed by a thermal treatment in NH 3 and H 2 atmospheres. The results showed that benzene with the initial concentration of 150 ppm (±5 ppm) could be thoroughly removed by N H TiO 2 under visible light irradiation. The influences of doping and hydrogenation on properties of TiO 2 samples were investigated. It is suggested that the disordered surface layer introduced by hydrogenation contributes to the excellent photocatalytic activity of N H TiO 2 . The synergistic effect of N doping and surface oxygen vacancies was also confirmed by ultraviolet–visible diffuse reflectance spectra and photoluminescence. Moreover, the diverse role of oxygen vacancies in different positions of TiO 2 has been focused on. [ABSTRACT FROM AUTHOR]

Highlights: [•] A thermally stable mesoporous ZrO2–CeO2–TiO2 was prepared. [•] The ZrO2–CeO2–TiO2 had a high surface area due to the enhanced thermal stability. [•] The ZrO2–CeO2–TiO2 had a good optical absorption capacity in the visible range. [•] The ZrO2–CeO2–TiO2 was effective for the degradation of Rhodamine B. [ABSTRACT FROM AUTHOR]

A highly efficient visible light driven photocatalyst was prepared by annealing samples continuously in ammonia and vacuum. The dependence of photocatalytic activity on calcination temperature was investigated. The effect of annealing temperature on crystal structure, particle size, chemical composition and optical absorbance of TiO 2 nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy and UV–visible diffuse reflectance spectroscopy, respectively. The photocatalytic degradation of benzene under visible light illumination demonstrated that the photocatalyst annealed at 600 °C (NV-TiO 2 -T600) possessed the best photocatalytic property. The excellent photocatalytic activity of NV-TiO 2 -T600 was attributed to the high crystallinity, strong light-harvesting and enhanced separation of photo-generated electron–hole pairs. The vacuum treatment had a positive effect on enhancing charge separation. In addition, the increased amount of surface oxygen vacancy might be the crucial factor for the improvement of photocatalytic activity. [ABSTRACT FROM AUTHOR]

Abstract: Novel heterojunction MgFe2O4–ZnO was employed as a photocatalyst to photodegrade organic pollutants Rhodamine B (RhB). This heterojunction was prepared by two steps. First, ZnO flower-like nanotube bundles were synthesized by using a simple solution method at low temperature. Second, MgFe2O4 was coated on ZnO surfaces on the basis of a chemical co-precipitation method. The as-prepared samples were characterized with X-ray diffraction (XRD), UV-3150 double-beam spectrophotometer, field-emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), and high-resolution transmission (HRTEM). Photodegradation experiments results indicated that the obtained heterojunction MgFe2O4–ZnO exhibited higher photocatalytic activity than that of pure ZnO or MgFe2O4. Furthermore, MgFe2O4–ZnO could be separated conveniently by using an external magnetic field. The enhanced photocatalytic ability of MgFe2O4–ZnO composites could be attributed to the interconnected heterojunction of MgFe2O4 and ZnO nanoparticles. [Copyright &y& Elsevier]