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• La/N co-doped TiO 2 /SrFe 2 O 4 /diatomite (LN-TSD) composite was prepared. • The visible-light-driven photoactivity of LN-TSD was investigated. • The optimal amount of co-dopant and catalyst dosage were determined. • The charge transfer between TiO 2 and SrFe 2 O 4 improved the photocatalytic activity. • The LN-TSD catalyst showed easy separation and good reusability after 5 recycles. Powdery photocatalyst has long been studied, yet its low reusability in suspension system is the bottleneck which hinders its large-scale application. An alternative method to overcome this drawback is developing magnetic recyclable composite. In this work, we prepared lanthanum-nitrogen co-doped titania/strontium ferrite/diatomite (LN-TSD) ternary composite via sol-gel technology. The as-prepared materials were characterized and analyzed, and the photocatalytic activity was evaluated via the elimination of antibiotic oxytetracycline (OTC) under visible light illumination. Charge transfer happened at the heterojunction interface between TiO 2 and strontium ferrite, and thus improved the photocatalytic efficiency by inhibiting the recombination of charge carriers. The photodegradation rate of OTC was accelerated by the high adsorption ability of substrate diatomite, due to the adsorption and degradation synergistic effect between photocatalytic components and substrate diatomite. The optimal dopant amount and catalyst dosage were determined, and the corresponding LN-TSD sample showed its degradation rate of OTC as 95.5% after 2.5 h. The ternary LN-TSD composite could simply be separated from OTC solution via an external magnet, and the repetition tests indicated that, after 5 turns of repetition, only slightly decrease of degradation rate could be observed (dropped to 94.2%). This composite was promising to be applied in wastewater remediation process, due to its good photocatalytic activity under visible light, as well as its good reusability and stability. [ABSTRACT FROM AUTHOR]

• BiOBr/BTO heterojunction catalysts were prepared by chemical precipitation method. • The catalyst exhibits highly efficient piezo-photocatalysis for degrading multi-pollutant. • Synergistic piezo-photocatalysis was realized under light illumination and ultrasound. • The catalyst shows favorable cycling stability and applicability for multi-pollutant. Piezo-catalysis is a green and effective method for degrading rich and obstinate molecules in wastewater. Yet, the piezo-catalytic performance of frequently-used barium titanate (BTO) is still limited for practical applications, thus it is crucial to construct high-efficiency BTO-based catalysts. Herein, BiOBr/BTO heterojunction-based piezo-photocatalysts were successfully prepared using the chemical precipitation method, and an internal electric field was established via ultrasound to promote the separation of photogenerated electron-hole pairs through the synergistic effect of piezocatalysis and photocatalysis. Transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy were utilized to characterize the heterojunction. The degradation performance of Rhodamine B (RhB) by BiOBr/BTO is the best among various pollutants, giving a reaction rate constant up to 20.839 × 10−2 min−1, exceeding numerous previously reported catalysts. In addition, the piezo-photocatalytic reaction rate of BiOBr/BTO for Methyl Orange was 9.298 × 10−2 min−1, ≈ 3.3 times than those of pure BTO (2.806 × 10−2 min−1), and also ≈ 15.9 times and 3.3 times than those of single photocatalysis (0.585 × 10−2 min−1) or piezocatalysis (2.848 × 10−2 min−1). Importantly, the BiOBr/BTO heterojunction demonstrates excellent catalytic degradation performance for a broad range of pollutants (e.g., dyes and antibiotics) and their mixtures, as well as favorable cycling stability and repeatability with changed environmental conditions, displaying applicability in actual wastewater treatment. The possible degradation pathways of RhB were analyzed by liquid chromatography-mass spectrometry. The present work supplies a feasible strategy for the preparation of high-efficiency piezo-photocatalytic BTO-based heterojunctions, which can guide other composites for environmental remediation. [ABSTRACT FROM AUTHOR]

• Sensitive photoelectrochemical method was developed for histone acetyltransferase detection. • WS 2 and black TiO 2 heterojunction presented strong photoelectrochemical response. • Solid electron donor of polydopamine can effectively improve the photoactivity of WS 2 and black TiO 2. • This method can also be applied for the inhibitor screening. A kind of novel heterojunction structure with black TiO 2 and WS 2 was prepared with matched energy band and significantly improved visible-light-driven photoelectrochemical activity. Then, to further improve the photoelectrochemical activity of this heterojunction, solid-state electron donor of polydopamine was employed with satisfactory result. The band gap, potential of conduction band and valence band was investigated using Mott-Schottky curve, VB-XPS and UV–vis diffuser reflectance techniques. These materials were also characterized by SEM, TEM, XRD, IR, Roman spectra, and EPR image. The improved photoactivity was confirmed by monitoring and comparing the photocurrent response of black TiO 2 , WS 2 and Black TiO 2 /WS 2 heterojunction. To explore the applicability of this novel heterojunction structure, a kind of photoelectrochemical biosensor was constructed for histone acetyltransferase p300 detection using black TiO 2 and WS 2 as photoactive material and polydopamine as electron donor. Under optimized conditions, the photoelectrochemical biosensor shows wide linear range from 0.01 to 500 nM for histone acetyltransferase p300 detection. The detection limit is 0.0033 nM (S/N = 3). The sensor has good selectivity, stability and reproducibility. The inhibition tests show that aminoglycoside antibiotics significantly inhibits the activity of histone acetyltransferase and the IC 50 of typical tobramycin, streptomycin sulfate and kanamycin sulfate were 10.41, 13.31 and 15.42 μM, respectively. [ABSTRACT FROM AUTHOR]