石墨烯量子点修饰的BiOI/PAN柔性纤维的制备及其增强的光催化活性

在环境治理中,光催化氧化是去除有机污染物的一种很有前途的技术。与吸附、生物降解和化学氧化等方法相比,光催化氧化可以通过环境友好的方式,完全、方便、廉价地消除有机污染物。光催化氧化中,又以可见光光催化氧化更具优势,这是因为可见光在太阳光中的能量比例较高。碘氧化铋(BiOI)是一种很有前途的可见光光催化剂,不仅具有较窄的带隙,而且具有较低的价带(VB),其产生的光生空穴能氧化分解多种有机污染物。然而,BiOI粉末回收困难、比表面积低、载流子复合快等缺点限制了其实际应用。同时,光催化剂的柔性和分级结构有利于这些材料的操作、回收和性能改进,也是非常可取的特性。为此,本文以j静电纺丝制备的聚丙烯腈(PAN)纳米纤维为基底,通过原位反应的方法,制备了具有分级结构的柔性BiOI/PAN复合纤维。在BiOI/PAN纤维中,BiOI薄片围绕PAN纤维、垂直均匀地排列在其表面,形成独特的分级结构。在制备的过程中,PAN纤维中掺入的Bi(Ⅲ)会先形成的BiOI晶核,并成为BiOI纳米片生长的种子。这对分级结构的形成至关重要。紫外-可见漫反射光谱和光致发光发射分析显示,这种分级结构可以改善BiOI/PAN光纤的光吸收,促进光生载流子的形成。因此,BiOI/PAN纤维比BiOI粉末具有更高的光催化活性。进一步,用预先制备的石墨烯量子点(GQDs)对BiOI/PAN纤维进行修饰,可制备出GQDs修饰的BiOI/PAN纤维复合材料(GQD-BiOI/PAN)。所制备GQD-BiOI/PAN的形貌与BiOI/PAN纤维几乎是一样的。通过制备方法、光致发光发射、反应自由基测试和X射线光电子能谱(XPS)的综合分析,证实了GQDs与BiOI之间会形成梯型(S型)异质结。这种S型异质结不仅能有效地抑制光生空穴的复合,而且能保留GQDs的最低未占据分子轨道(LUMO)上还原能力更强的电子,以及BiOI的VB上氧化能力更强的空穴,用于光催化降解苯酚。在纤维分级结构和S型异质结的共同作用下,GQD-BiOI/PAN在可见光光催化氧化苯酚中,其性能明显优于BiOI粉末和BiOI/PAN纳米纤维。此外,由于粘结紧密,GQD-BIOI/PAN可以进行裁剪和徒手操作,回收利用非常方便。在循环性能测试中,没有明显的样品损失和光催化活性的降低的现象。本文的工作为制备柔性光催化剂提供了一条新的途径,并对光催化剂的增强提供了新的视野。

The embedded CuInS2 into hollow-concave carbon nitride for photocatalytic H2O splitting into H2 with S-scheme principle

It is still a great challenge to effectively optimize the electronic structure of photocatalysts for the sustainable and efficient conversion of solar energy to H2 energy.To resolve this issue,we report on the optimization of the electronic structure of hollow-concave carbon nitride(C3N4)by deviating the sp2-hybridized structure of its tri-s-triazine component from the two-dimensional plane.The embedded CuInS2 into C3N4(CuInS2@C3N4)demonstrates an increased light-capturing capability and the promoted directional transfer of the charge carrier.Research results reveal that the hollow structure with an apparent potential difference between the concave and convex C3N4 drives the directional transfer of the photoinduced electrons from the Cu 2p orbital of CuInS2 to the N 1s orbital of C3N4 with the S-scheme principle.The H2 evolution efficiency over CuInS2@C3N4 is up to 373μmol?h^-1 g^-1 under visible irradiation,which is 1.57 and 1.35 times higher than those over the bulk g-C3N4 with 1 wt%Pt(238μmol?h^-1 g^-1)and g-C3N4 with 3 wt%Pd(276μmol?h^-1 g^-1),respectively.This suggests that the apparent potential difference of the hollow C3N4 results in an efficient reaction between the photogenerated electrons and H2O.This work supplies a new strategy for enhancing the sustainable solar conversion performance of carbon nitride,which can also be suitable for other semiconductors.

Electrodeposited iodide ions imprinted polypyrrole@bismuth oxyiodide film for an electrochemically switched renewable extractor towards iodide ions

Effective extraction and regeneration of radioactive iodide is one of urgent concerns for the safe utilization of nuclear energy.As a novel environmentally benign ion separation technique,electrochemically switched ion extraction(ESIE)process can be applied for effective capture and recovery of iodide ions(I^(-)).Herein,a novel kelp seaweed-like core/shell I^(-)imprinted polypyrrole@bismuth oxyiodide(PPy/I^(-)@BiOI)composite film is successfully prepared for the selective I^(-)capture in the ESIE system.It is found that the I^(-)can be easily trapped in the PPy/I^(-)@BiOI film after I^(-)is in situ desorbed from the film by an electrochemical reduction process since it offers particular electroactive binding sites for I^(-)extraction.The I^(-)imprinted PPy/I^(-)@BiOI film displays an extraction capacity as high as 325.2 mg·g^(-1)for I^(-)with favorable stability.In particular,the extraction and desorption of I^(-)is achieved by adjusting the redox potential and the pristine PPy/I^(-)@BiOI film can be regenerated and reused for multiple times without decrease in extraction capacity.It is expected that such a PPy/I^(-)@BiOI film would be useful as an electrochemically switched renewable extractor that could capture and regenerate I^(-)from radioactive water.

Clinical Efficacy of Hyperbaric Oxygen Therapy at Different Pressures in the Treatment of Sudden Deafness

Objective:To analyze the efficacy of hyperbaric oxygen at different pressures in the treatment of sudden deafness.Methods:Eighty-two patients with sudden deafness treated in the Affiliated Hospital of Hebei University from September 2019 to September 2021 were selected as the research subjects.The patients were randomly divided into study group 1 and study group 2,and they were treated with hyperbaric oxygen on the basis of routine treatment,in which the pressure used was 1.8 ATA and 2.2 ATA,respectively.Oxygen was delivered via the pressure stabilizing mask for 60 minutes.The patients received two courses of treatment,each lasting 10 days.The changes in hearing(pure tone audiometry)and the clinical efficacy of both the groups were compared before and after treatment.The data obtained were statistically analyzed using SPSS 19.0.Results:The total effective rate of study group 1 was 90.00%,while that of study group 2 was 76.19%.The differences between the two groups were statistically significant(p<0.05).Conclusion:For patients with sudden deafness treated with hyperbaric oxygen,the clinical efficacy of 1.8 ATA is more significant than that of 2.2 ATA.

Observation on the Clinical Effect of Different Pressures in Hyperbaric Oxygen Therapy on Patients with Diffuse Axonal Injury

Objective:To observe the efficacy and significance of hyperbaric oxygen at different pressures in the treatment of diffuse axonal injury(DAI).Methods:Sixty patients with DAI were randomly divided into 1.8 ATA group(30 cases)and 2.2 ATA group(30 cases).The routine treatment for each group was the same.The 1.8 ATA.group received hyperbaric oxygen therapy under 1.8 ATA on the basis of routine treatment,whereas the 2.2 ATA group received hyperbaric oxygen therapy under 2.2 ATA.on the basis of routine treatment.The therapy was given once a day over 3 consecutive courses,with each course having 10 sessions.The Glasgow Coma Scale(GCS)on day 10,day 20,and day 30 after treatment,as well as the Glasgow Outcome Scale(GOS)after 6 months were compared between the two groups.Results:The mean GCS on day 10,day 20,and day 30 after treatment,as well as the mean GOS after 6 months of treatment in the 2.2 ATA group were significantly higher than those in the 1.8 ATA group(p<0.05).Conclusion:For patients with dififtise axonal injury,hyperbaric oxygen therapy is more effective with 2.2 ATA.compared with 1.8 ATA.

Paclitaxel and cisplatin with or without cetuximab in metastatic esophageal squamous cell carcinoma:a randomized,multicenter phase II trial

Lack of effective targeted therapy in metastatic esophageal squamous cell carcinoma(ESCC)underscores the urgent need for identifying new treatment approaches for this challenging disease.We sought to assess the addition of cetuximab to paclitaxel-cisplatin chemotherapy for first-line treatment in patients with metastatic ESCC.In this randomized,multicenter,open-label,phase II clinical trial,patients were randomized to receive paclitaxel-cisplatin(TP)(paclitaxel[175 mg/m^(2) intravenously(i.v.)on day 1 of every 3-week cycle]and cisplatin[75 mg/m^(2) i.v.on day 1 of every 3-week cycle])and TP plus cetuximab(CTP)(cetuximab,400 mg/m^(2) i.v.on day 1 of week 1,followed by 250 mg/m^(2) weekly).