Rational design of photocatalyst to maximize the use of sunlight is one of the issues to be solved in photocatalysis technology. In this study, the CuFe 2 O 4 @C/Cd 0.9 Zn 0.1 S (CFO@C/CZS) S-scheme photocatalyst with photothermal effect was synthesized by ultrasonic self-assembly combined with calcination. The dark CFO@C absorbed visible light and partly converted into heat to promote the hydrogen evolution reaction. The presence of heterojunctions inhibited the photogenerated electron-hole recombination. The graphite-carbon layer provided a stable channel for electron transfer, and the presence of magnetic CFO made recycle easier. Under the action of photothermal assistance and heterojunction, the hydrogen evolution rate of the optimal CFO@C/CZS was 80.79 mmol g −1 h −1 , which was 2.55 times and 260.61 times of that of pure CZS and CFO@C, respectively. Notably, the composite samples also exhibit excellent stability and a wide range of environmental adaptability. Through experimental tests and first-principles simulation calculation methods, the plausible mechanism of photoactivity enhancement was proposed. This work provided a feasible strategy of photothermal assistance for the development of heterojunction photocatalysts with distinctive hydrogen evolution.
Liu Yang,Yu-Han Sun,Xian-Xian Ji,Yuan-Zhen Wang,Yu-Long Liu,Ying Fu,Fei Ye
Triflumuron is an insect growth regulator belonging to the class of insecticides. It finds its primary application in the agricultural sector for the control of various pests, particularly certain beetles, aphids, locusts, and mites. In this paper, a Cu/Fe-BTC composite was synthesized through a straightforward solvothermal approach, subsequently employed as a precursor for the fabrication of an electrochemical sensor denoted as CuFe 2 O 4 @C . The latter exhibited a distinctive core-shell architecture achieved through annealing, and its application was focused on the sensitive detection of triflumuron. The electrochemical behaviour of CuFe 2 O 4 @C for the detection of triflumuron was evaluated by differential pulse voltammetry (DPV) under optimal conditions in wide concentrations from 1.0 × 10 −4 to 1.0 × 10 −12 mol·L −1 , where there existed a superior linear relationship between the current and the concentration of triflumuron with R 2 being 0.995. Meanwhile, CuFe 2 O 4 @C had a low limit of detection (LOD) of 922 fM for triflumuron. The CuFe 2 O 4 @C/GCE exhibited remarkable sensitivity, long-term stability, excellent reproducibility, and repeatability, as well as effective anti-interference capabilities. Additionally, CuFe 2 O 4 @C demonstrated its applicability for the quantitative determination of triflumuron in diverse real samples with commendable recovery rates. In conclusion, the electrochemical sensor not only displayed exceptional performance in terms of stability, reproducibility, and anti-interference, but also showcased its practical utility in quantifying triflumuron across various real-world samples.
Menghe Liu,Congyang Zou,Yong Wang,Zhuyou Zhou,Yufeng Ji
In this paper, the precursors of the target product were prepared using a simple solvothermal method. After pyrolysis of the precursors, a three-dimensional Fe/CuFe2O4@C (referred to as FCC) nanomaterial with a relief texture was successfully prepared, which was employed as a novel catalyst material for activated persulfate (referred to as PS) degradation, tetracycline (referred to as TC), in wastewater. X-ray photoelectron spectroscopy (XPS) revealed that Fe(III) and Cu(II) served as the primary active metal ions, while the formation of a surface carbon shell positively influenced electron transfer during catalytic degradation. A comprehensive investigation was conducted to assess the efficiency of FCC nanocatalysts in degrading TC under various conditions. The results demonstrated that the degradation rate of TC in the 100 min range was about 96% at concentrations of 0.2 g L−1 FCC and 1 mmol L−1 persulfate and pH 7. Quenching experiment results and EPR results consistently indicated that both free radical and non-radical pathways involved in TC degradation by FCC nanomaterials, and sulfate radicals, hydroxyl radicals, superoxide radicals and singlet oxygen were identified to be the main active substances. The degradation intermediates were analyzed by liquid mass spectrometry and toxicology. FCC, as a catalyst exhibiting high catalytic activity, demonstrates superior performance in the activated persulfate degradation of TC. The environmental risk associated with the degradation of intermediate products is significantly lower than that of TC itself. FCC holds significant potential for the degradation of antibiotics in wastewater.
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