Graphene-like h-BN supported polyhedral NiS2/NiS nanocrystals with excellent photocatalytic performance for removing rhodamine B and Cr(VI)

Human health is deteriorating due to the effluent containing heavy metal ions and organic dyes. Hence, photoreduction of Cr(VI) to Cr(III) and degradation of rhodamine B (RhB) using a novel photocatalyst is particularly important. In this work, h-BN/NiS₂/NiS composites were prepared via a simple solvothermal method and a double Z-scheme heterojunction was constructed for efficiently removing RhB and Cr(VI). The 7 wt-% h-BN/NiS₂/NiS composites were characterized via a larger specific surface area (15.12 m²·g^–1), stronger light absorption capacity, excellent chemical stability, and high yield of electrons and holes. The experimental result indicated that the photoreduction efficiency of the 7 wt-% h-BN/NiS₂/NiS photocatalyst achieved 98.5% for Cr(VI) after 120 min, which was about 3 times higher than that of NiS₂/NiS (34%). However, the removal rate of RhB by the 7 wt-% h-BN/NiS₂/NiS photocatalyst reached 80%. This is due to the double Z-scheme heterojunction formed between NiS₂/NiS and h-BN, which improved the charge separation efficiency and transmission efficiency. Besides, the influence of diverse photogenerated electron and hole scavengers upon the photoreduction of Cr(VI) was studied, the results indicated that graphene-like h-BN promoted transportation of photoinduced charges on the surface of the h-BN/NiS₂/NiS photocatalyst via the interfacial effects.     

四酰胺基四(1,4-二噻英)四氮杂卟啉的合成

以2,3-二氰基-5-酰胺基-1,4-二噻英为前驱体,利用镁模板法在较温和的条件下合成了四酰胺基四(1,4-二噻英)四氮杂卟啉自由配体,目标产物的终产率为42%,并通过1H-NMR、UV-Vis、XPS等表征手段进行了初步表征。有待进一步合成四酰胺基四(1,4-二噻英)四氮杂卟啉金属配合物。四酰胺基四(1,4-二噻英)四氮杂卟啉金属配合物可用于在模拟太阳光的条件下降解罗丹明B、甲基橙等染料。     

2D\2D g-C3N4-rGO的构筑及其界面效应研究

以三聚氰胺和氧化石墨为原料，于N2气氛下构筑了一系列2D/2D g C3N4 rGO (CN RGO)界面复合材料，对其进行SEM、TEM、UV Vis、XRD和FT IR等表征，考察界面效应对催化剂性能的影响。UV Vis结果表明，相比纯 g C3N4（CN），CN RGO的可见光吸收范围明显提升。同时，CN RGO 2界面复合材料的光催化性能明显高于纯CN，对罗丹明B降解率达到了858%，这可能由于CN上产生的电子（e-）通过界面效应转移到rGO上，促进空穴（h+）和e-迅速分离。淬灭实验结果表明，h+和O-2·在RhB光降解过程中的作用比·OH与H2O2更重要。该研究为其它2D/2D界面复合材料的设计和应用提供了重要基础。     

Synthesis of silicon nanowires supported Ag nanoparticles and their catalytic activity in photo-degradation of Rhodamine B

Silver modified silicon nanowires were obtained and employed as photo-catalysts in the dcgradation of Rhodamine B (RhB), which demonstrated the excellent catalytic activity. These catalysts may be recycled and reused.     

温度对罗丹明B水溶液荧光强度影响研究

配制了3种不同浓度的罗丹明B(Rh B)水溶液,分别测量其在低温和高温条件下的发射光谱。结果表明,无论在低温过程或高温过程,罗丹明B水溶液的荧光强度都随温度的升高而降低,反之增加。由低温5℃升至室温过程中,荧光强度与温度呈线性关系,在由高温60℃降至室温过程中,60~40℃和40~30℃两个温度区间,温度与荧光强度呈现两种不同的关系,40~30℃温度区间内是线性关系。但高温自然降温至室温的罗丹明B溶液与低温自然升温至室温的罗丹明B溶液荧光光强会发生突变,这表明罗丹明B在低温(0℃)和高温(70℃)下保温时发生了部分不可逆的反应。     

改进溶液燃烧法制备Fe3+掺杂Bi24O31Cl10及其光催化性能的研究

采用改进溶液燃烧法,以硝酸铋、柠檬酸、氯化铵和硝酸铁为原材料制备Fe-Bi24O31Cl10光催化物质,并通过在可见光下降解RhB评价Fe^3+掺杂对其光催化性能的影响。采用XRD,XPS,UV-vis,SEM,HTEM,FT-IR等表征手段研究了不同Fe^3+掺杂量对Bi24O31Cl10的物相、元素价态、光吸收性能、微观形貌以及颗粒分布、晶面间距、化学结构组成等的影响。结果表明:掺杂Fe^3+未改变Bi24O31Cl10的物相,片状形貌,但其片状大小明显变小且厚度变薄,光吸收性能增强,光生电子-空穴复合率下降,与纯Bi24O31Cl10相比,Fe^3+掺杂能显著提高Bi24O31Cl10的光催化活性,当Fe^3+掺杂量为0.5%(摩尔分数)时,对Bi24O31Cl10的光催化性能促进最高,在可见光下光照50 min,对RhB的脱色率可达75%,较纯Bi24O31Cl10提高了44%。     

紫外辐射诱发自由基体系及抗氧化活性的研究

建立了紫外辐射诱发活性氧自由基体系和检测自由基的新方法。采用该方法测定了抗氧化剂三七皂苷Rb1,三七皂苷Rg1,芦荟多糖,野甘草多糖,凤尾茶多糖,抗坏血酸的抗氧化活性和去除氧自由基的清除率,结果表明植物活性多糖清除活性氧自由基的效果较抗坏血酸(维生素C)效果好,此法可用于活性氧自由基清除剂的筛选研究。     

1种新的催化动力学光度法测定痕量锰

基于HAc-NaAc溶液中,以氨三乙酸为活化剂,锰催化高碘酸钾氧化罗丹明B的反应,建立了1种催化动力学光度法测定痕量锰的新方法.实验的最佳操作条件为:pH=4.7的HAc-NaAc缓冲溶液、高碘酸钾溶液、氨三乙酸溶液和罗丹明B溶液用量分别为2.0mL,1.0 mL,1.0 mL和2.0 mL;最低检出限为0.021 1μg/L,测定的线性范围为(2～16μg/L).应用于测定自来水中痕量锰和余甘中锰含量,结果满意.     

Influence of Hydrogenation on Morphology,Chemical Structure and Photocatalytic Efficiency of Graphitic Carbon Nitride

In this contribution, the effect of hydrogenation conditions atmosphere (temperature and time) on physicochemical properties and photocatalytic efficiency of graphitic carbon nitride (g-C₃N₄, gCN) was studied in great details. The changes in the morphology, chemical structure, optical and electrochemical properties were carefully investigated. Interestingly, the as-modified samples exhibited boosted photocatalytic degradation of Rhodamine B (RhB) with the assistance of visible light irradiation. Among modified gCN, the sample annealed at 500 °C for 4 h (500-4) in H₂ atmosphere exhibited the highest photocatalytic activity—1.76 times higher compared to pristine gCN. Additionally, this sample presented high stability and durability after four cycles. It was noticed that treating gCN with hydrogen at elevated temperatures caused the creation of nitrogen vacancies on gCN surfaces acting as highly active sites enhancing the specific surface area and improving the mobility of photogenerated charge carriers leading to accelerating the photocatalytic activity. Therefore, it is believed that detailed optimization of thermal treatment in a hydrogen atmosphere is a facile approach to boost the photoactivity of gCN.