It is of great significance to achieve superior degradation of contaminants by developing efficient and stable photocatalysts . To boost the photocatalytic performance of Bi 2 WO 6 for tetracycline degradation, the Bi 2 WO 6 composites ( Bi 2 WO 6 /C@Cu 2 O) were constructed by introducing Cu 2 O coated by carbon layer (C@Cu 2 O with 5 wt% of Bi 2 WO 6 ) in this study. Bi 2 WO 6 /C@Cu 2 O presents an excellent performance on tetracycline degradation because of the generation of more active species as ∙ O 2 - and ∙ OH. Its kinetic rate constant k was 2.8 times of pure Bi 2 WO 6 and tetracycline degradation efficiency maintained outstanding stability even after 4 cycles. This benefits from the higher photogenerated charge separation and electron transfer possessed by Bi 2 WO 6 /C@Cu 2 O compared to Bi 2 WO 6 . Various intermediates of tetracycline degradation were identified and the possible degradation pathways were proposed. The tetracycline degradation by Bi 2 WO 6 /C@Cu 2 O followed a Z-scheme photocatalysis mechanism. In addition to acting as the protective layer of Cu 2 O to attenuate the photo-corrosion of Cu 2 O, the oxygen containing functional groups C O on the surface of carbon layer could provide an electron transfer channel between the interface of Bi 2 WO 6 and Cu 2 O to reduce the interfacial charge-transfer resistance and accelerate the electron transfer.
Song Ziyan,Ma Ruolong,Zheng Xiaodan,Zhang Limeng,Ruan Chuanda,Yan Xiaohui,Tian Fei
In this study, Fe 3 O 4 @C@Cu 2 O was synthesized using a solvothermal method. The morphology and structural characteristics of the material were systematically investigated through various characterization techniques, including TEM, XPS, FT-IR, DLS, and VSM. Its antibacterial efficacy was assessed through colony counting. Results showed that at a concentration of 0.5 mg/mL, Fe 3 O 4 @C@Cu 2 O nanoparticles with a copper atomic percentage of 2.42% achieved bactericidal rates of 98.45% against E. coli and 90.58% against S. aureus . Compared to pure Fe 3 O 4 @C and Cu 2 O, the composite material demonstrated a 100% bactericidal rate against E. coli and 99.23% against S. aureus . Notably, after five cycles, the composite nanoparticles maintained effective bactericidal rates, with 82.16% against S. aureus and 94.72% against E. coli . SEM images of bacterial morphology and EPR tests confirmed that the antibacterial mechanism primarily involves the generation of reactive oxygen species(ROS).
Silicon monoxide (SiO x , 0 < x < 2) has been one of the new directions of scientific researchers because of some characteristics, such as higher theoretical specific capacity and lower volume expansion efficiency. However, its disadvantages such as the volume expansion effect and poor conductivity still exist in the process of charge and discharge, which limit its commercialization process. In this paper, cuprous oxide and carbon coated silicon monoxide (SiO x /C/Cu 2 O) composites were obtained by high temperature heat treatment. In the SiO x /C/Cu 2 O anodes, carbon can buffer the volume expansion of the lithium intercalation, enhance the conductivity of the material, reduce the contact between the electrolyte and the active substance, Cu 2 O can further reduce the contact between the electrolyte and the active substance, greatly buffer the change of electrode structure and improve the overall cycling performance. After the rate of 0.5C (1C = 2100 mA g −1 ) for 500 cycles, the discharge specific capacity is 704.0 mAh g −1 , about 350 mAh g −1 higher than SiO x , which shows excellent long-cycle ultra-high stability.
Peroxymonosulfate (PMS) is an alternative disinfectant for drinking water . This study aimed to investigate the transformation of iopamidol (IPM) catalyzed by a main copper corrosion product ( c -Cu 2 O) with PMS as a disinfectant. The observed pseudo-first-order constant ( k obs ) for the IPM degradation in the c -Cu 2 O/PMS system (0.033 min −1 ) was 3 times that in the CuO/PMS system (0.011 min −1 ). The quenching tests and the electron paramagnetic resonance (EPR) experiments indicate that O 2 •− and 1 O 2 contributed to IPM degradation in the c -Cu 2 O/ PMS system. The complexation of metastable Cu(II) with a PMS molecule polarized the O O bond and then facilitated the electron transfer from the PMS molecule to other PMS and O 2 molecules, which directly and indirectly promoted the yield of O 2 •− and 1 O 2 . The iodine balance indicated that 26.0% of initial TOI was converted to IO 3 − , and CHI 3 only accounted for 0.6% of the residual TOI. In the c -Cu 2 O/PMS system, IPM conversion was started with amide C−N bond breakage, deiodination reaction and hydrogen abstraction. This study helps to better understand the conversion mechanisms of iodine-containing organic micropollutants when PMS is deployed as a disinfectant in copper pipes.
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