Shengchao Miao,Zhenxing Zha,Ying Li,Xinxiang Geng,Jiahui Yang,Shihai Cui,Jing Yang
The novel semiconductor heterojunction of MIL-53(Fe)/BiOCl composite was first prepared through the solvothermal reaction. The prepared materials were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunner-Emmet-Teller (BET) and ultraviolet-visible diffuse reflectance spectroscopy (DRS). MIL-53(Fe)/BiOCl heterojunction is a kind of photoexcited materials and it accelerates the photoreactivity of BiOCl under the visible light irradiation. It was used to remove Rhodamine B (RhB) with the existence of persulfate (PS). The UV–vis spectrophotometer and the TOC detector show that the degradation rate and TOC removal efficiency of RhB (20 mg/L) are 99.5% and 69.4%within 30 min visible-light irradiation, respectively. Due to the proper band gap of material and the presence of electron acceptor, PS, the survival time of active radicals are increased. The active species h + , ·SO 4 − and ·OH are found to play the important roles during the reaction system. The possible mechanism for the RhB degradation of MIL-53(Fe)/BiOCl/PS is also proposed. Furthermore, the results of the material reusability for the degradation of RhB indicate that the MIL-53(Fe)/BiOCl has a good stability and can be used in the environmental water sample treatment.
Metal ion doping is an efficient method to achieve high photocatalytic performance of semiconductors. However, the current synthetic methods by using inorganic salts as doped sources in the precursor reaction system might suffer from ion waste and second pollution. Herein, we developed a novel method by employing electrospun nanofibers as ion reservoir to release metal ions for the synthesis of ion-doped semiconductors with high photocatalytic activity . As demonstrated, Co/Fe co-doped BiOCl photocatalyst (Co/Fe-BOC) was facilely prepared in the presence of CoFe 2 O 4 nanofibers as Co and Fe ion reservoir via a simple solvothermal method . Compared with BiOCl, the resulted Co/Fe-BOC shows increased specific surface area, visible light response as well as separation and transportation efficiencies of photogenerated carriers. Thus, the Co/Fe-BOC exhibits significantly enhanced visible light photocatalytic activity to degrade 99.4% rhodamine B (RhB) within 4 min. This new doping approach not only avoids the ion waste and pollution during the reaction process but also facilitates the separation of the photocatalyst. Moreover, the CoFe 2 O 4 nanofibers could be repeatedly used as ion reservoir to prepare high-performance Co/Fe-BOC. This nanofiber-based ion doping approach provides a novel, universal and promising insight to obtain doped semiconductors with high photocatalytic activity.
Excess reactive oxygen species (ROS) produced by abnormal mitochondria is one of the critical triggers of rheumatoid arthritis (RA). Existing nanocatalytic therapies can only catalyze the breakdown of ROS but cannot address the root cause of ROS production, i.e., abnormal mitochondria. Here, we designed an ultrasound (US) piezoelectric catalytic therapy, which can induce mitophagy in a spatiotemporally controlled manner to treat RA. The prepared two-dimensional piezoelectric nanosheets (NSs) Fe/BiOCl with US catalytic activity can efficiently generate electrons under US stimulation to meet the purpose of consuming H+ in the outer mitochondrial membrane and disturbing the H+ supply in the mitochondrial matrix. This causes depolarization of the mitochondrial membrane potential (MMP), triggering the autophagy of mitochondria in regions of inflammation to eliminate the source of ROS regeneration. Analysis of cellular and RA model-related experiments showed that piezoelectric US-catalyzed therapy involving Fe/BiOCl NSs alleviated RA by inducing mitophagy. This provides an explanation of the mechanism for piezoelectric US catalytic therapy and suggests promising strategies for biomedical applications of US piezoelectric materials.
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