多元复合石墨相氮化碳/磷酸银光催化性能研究进展

石墨相氮化碳/磷酸银材料是一种很好的可见光光催化剂,但仍存在一些挑战和问题,限制了其实际应用能力。本文梳理总结了国内外利用银纳米粒子、碳材料、二维层状过渡金属硫化物、支撑材料、磁性Fe_3O_4、其他材料等对石墨相氮化碳/磷酸银复合改性的研究进展,介绍了其制备方法、应用、光催化增强机理等。本综述可以对后期石墨相氮化碳/磷酸银光催化剂的改性研究提供参考。     

片状石墨相氮化碳的制备及光催化性能研究

以三聚氰胺为前驱体,采用高温煅烧法、水热法预处理法、氨基修饰法以及氮气二次煅烧(热剥离法)制备g-C₃N₄,并对样品进行了结构表征与分析,并进行了光催化性能及稳定性测试。结果表明：四种制备方法对样品的光催化活性有显著的影响,热剥离法制备的样品有较好的光催化性能,氨基改性法制备的样品具有较好的稳定性能,可以多次重复使用。     

甲酸铵处理对氮化碳光催化性能的影响

石墨相氮化碳(g-C₃N₄)作为环境友好型材料在半导体光催化领域广受关注,然而未经改性的g-C₃N₄光吸收范围窄,仅能对太阳光谱中蓝紫光区响应,同时比表面积小,且光生载流子分离及迁移速率慢,导致光催化性能不佳。本文以g-C₃N₄为研究对象,将甲酸铵(NH₄HCO₂)和硫脲(CH₄N₂S)按不同比例混合,在马弗炉中520℃下高温煅烧(升温4 h保温2 h),制得C元素掺杂的石墨相氮化碳。g-C₃N₄中掺杂C元素可提高光吸收能力、调整电荷密度、促进光生载流子解离,从而显著提高其光催化效率。通过降解模拟污染物罗丹明B(RhB)发现,当n(CH₄N₂S)∶n(NH₄HCO₂)=1∶0.04时表现出最好的光催化活性,其对罗丹明B的降解效率几乎能达到1...     

石墨相氮化碳材料及其光催化应用

石墨相氮化碳具有独特的电子能带结构和优异的化学稳定性,作为一种不含金属成分的新型可见光光催化剂,在光催化领域有着广泛的应用前景。介绍了近年来石墨相氮化碳的研究现状,重点探讨其合成方法、结构特性和其相关的衍生物以及在光催化中的应用。     

石墨相氮化碳的光催化应用研究

光催化技术利用太阳能激发出半导体的氧化还原活性,是一项环境友好型技术。石墨相碳氮碳(g-C₃N₄)是一种非金属半导体聚合物,它在各类光催化研究中表现出优异的光催化活性。总结了光催化技术在减缓化石能源危机和解决环境污染方面的应用,论述了g-C₃N₄在各技术中的光催化反应原理,并扼要分析了g-C₃N₄在光催化领域的发展趋势。     

硫酸胍制备多孔石墨型氮化碳及其光催化降解苯酚

为了增加比表面积和提高催化活性,一种无毒和易得的前驱体硫酸胍被首次用于制备石墨型氮化碳(g-C_3N_4)。用X射线粉末衍射、红外光谱、扫描电镜、透射电镜、N_2吸附-脱附、光电子能谱、紫外-可见光吸收光谱和荧光光谱对所得多孔g-C_3N_4进行表征。与由三聚氰胺为前驱体制备的体相g-C_3N_4相比,硫酸胍为前驱体制备的多孔g-C_3N_4具有更高的比表面积、发达的孔结构和较好的光电性能。以光催化降解苯酚为模型反应考察催化剂性能,结果表明,所得多孔g-C_3N_4的催化活性明显高于体相g-C_3N_4。优异的光催化性能和简单的合成方法使硫酸胍制备的多孔g-C_3N_4可广泛用于环境和能源领域。     

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.     

Research Progress on Graphitic Carbon Nitride/Metal Oxide Composites: Synthesis and Photocatalytic Applications

Although graphitic carbon nitride (g-C₃N₄) has been reported for several decades, it is still an active material at the present time owing to its amazing properties exhibited in many applications, including photocatalysis. With the rapid development of characterization techniques, in-depth exploration has been conducted to reveal and utilize the natural properties of g-C₃N₄ through modifications. Among these, the assembly of g-C₃N₄ with metal oxides is an effective strategy which can not only improve electron–hole separation efficiency by forming a polymer–inorganic heterojunction, but also compensate for the redox capabilities of g-C₃N₄ owing to the varied oxidation states of metal ions, enhancing its photocatalytic performance. Herein, we summarized the research progress on the synthesis of g-C₃N₄ and its coupling with single- or multiple-metal oxides, and its photocatalytic applications in energy production and environmental protection, including the splitting of water to hydrogen, the reduction of CO₂ to valuable fuels, the degradation of organic pollutants and the disinfection of bacteria. At the end, challenges and prospects in the synthesis and photocatalytic application of g-C₃N₄-based composites are proposed and an outlook is given.     

Significantly Strengthening Epoxy by Incorporating Carbon Nanotubes/Graphitic Carbon Nitride Hybrid Nanofillers

Novel hybrid nanofillers consist of carbon nanotubes (CNTs) and graphitic carbon nitride (g‐C₃N₄) are prepared for the enhanced mechanical properties of epoxy by improving the dispersion of CNTs. 2D planar structure, large surface area, and plentiful of surface reactive groups of g‐C₃N₄ efficiently resist the microcrack propagation, impede the thermal transfer, and provide chemical bonding with epoxy chains. The well‐dispersed CNTs by anchoring on g‐C₃N₄ surface promotes the efficient transfers of stress, and supply the stronger mechanical interlocking for interfacial bonding. The significantly enhanced mechanical properties of epoxy containing hybrid nanofillers are based on the synergistic effects between CNTs and g‐C₃N₄. Compared with neat epoxy, the tensile strength, tensile modulus, and storage modulus of epoxy containing 0.5 wt% hybrid nanofillers (CNTs: g‐C₃N₄ = 1: 9, w/w) below glass transition temperature (T_g) are increased by 37.65%, 29.36%, and 32.92%, respectively. Meanwhile, the T_g, onset decomposition temperature and char residue are also obviously raised.     

硫酸根改性g-C3N4的制备及其催化性能

采用酸水热后处理法制备了具有优异光催化合成双氧水性能的硫酸根改性石墨相氮化碳纳米棒催化剂。采用XRD、N_2吸附脱附、UV-Vis、FTIR、SEM、XPS、TPD、EIS及荧光光谱对催化剂进行表征。结果显示:硫酸根的引入改变了催化剂的结构性质、光学性质和氧气吸附能力。以高压钠灯为光源,乙二胺四乙酸为空穴捕获剂,所制备的硫酸根改性氮化碳催化剂的双氧水平衡浓度为2.7 mmol/L,是纯氮化碳的2.7倍。所制备的硫酸根改性氮化碳催化剂的双氧水平衡浓度为2.7 mmol/L,是纯氮化碳的2.7倍。     

氮化硼/碳纤维复合织物的性能研究

将氮化硼粉末负载于碳纤维织物上,用扫描电镜和紫外分光光度计观察和测试了氮化硼/碳纤维复合织物的表面形貌和紫外漫反射性能。结果显示:有大量氮化硼负载于碳纤维织物上;在250～600 nm波长范围,氮化硼/碳纤维复合织物的紫外漫反射性能比纯碳纤维织物的更好。用网络分析仪测试了氮化硼/碳纤维复合织物的电磁屏蔽性能,发现负载了氮化硼的碳纤维织物的电磁屏蔽性能略弱于纯碳纤维织物。     

碳微球负载Ag_3PO_4的合成与其光催化性能

以碳微球(CMSs)为载体,采用离子交换法制备了CMSs负载的磷酸银复合材料(CMSs/Ag3PO4)。对合成的CMSs/Ag3PO4复合材料的相组成、表面形貌和紫外-可见(UV-Vis)吸收光谱进行了表征,通过可见光催化降解甲基橙实验对所制备的CMSs/Ag3PO4复合材料的光催化活性进行了考察。结果表明:CMSs颗粒大小在100~200 nm,CMSs/Ag3PO4颗粒大小在200~250 nm;CMSs/Ag3PO4在可见光范围有强吸收,在可见光照射下,CMSs/Ag3PO4能有效地降解甲基橙,光照射60min对甲基橙的降解率可以达到92.5%;循环使用5次后,对甲基橙的降解率仍然保持为86.2%。     

复合纳米棒状Ag3PO4/ZnO材料的光催化性能

以一维棒状ZnO为载体,采用原位生长法制备纳米棒状Ag_3PO_4/ZnO复合材料。通过XRD、SEM、TEM、XPS和UV-Vis-DRS等测试对纳米棒状Ag_3PO_4/ZnO复合材料进行了表征,并评价了样品在可见光下的光催化性能。结果显示,ZnO几乎无可见光活性,通过水热法制备的ZnO形貌发生了改变,为比表面积的增加做出了贡献,为Ag_3PO_4提供了更多的负载可能。在可见光照射下,纯ZnO和Ag_3PO_4对苯酚的降解率分别为20%和38%,复合材料Ag_3PO_4/ZnO对苯酚的降解率为91.24%,光催化降解性能明显高于纯ZnO和Ag_3PO_4。最后,光催化稳定性的研究证明,Ag_3PO_4/ZnO复合材料形成了有效的异质结结构,抑制了电子-空穴的复合,提高了Ag_3PO_4/ZnO复合材料的稳定性。     

核壳结构纳米TiO_2/PU/PMMA复合材料制备及其光催化性能研究

采用纳米TiO2有机化改性、加成及原位乳液聚合,制备了纳米TiO2、聚氨酯(PU)、聚丙烯酸酯(PMMA)的复合材料。透射电镜形貌表明:合成了以纳米TiO2为核,PU与PMMA为壳的核壳结构的复合材料。研究了该复合材料的光催化性能。     

Si3N4及其复合材料强韧化研究进展

简述了氮化硅陶瓷的结构、性能和制备工艺，并分别通过自增韧补强、纤维／晶须强韧化、层状结构强韧化、相变强韧化以及颗粒弥散强韧化等方法对氮化硅陶瓷的强韧化研究进行了分类叙述。     

类石墨氮化碳及其MCA杂化物的合成与阻燃

采用三聚氰胺作为原料,通过梯度加热制备了类石墨氮化碳(g-C3N4),再以三聚氰胺、氰尿酸和自制g-C3N4合成了三聚氰胺氰尿酸杂化物(CNMCA)。采用FTIR、XRP和TDA对g-C3N4和CNMCA的结构与热性能进行了表征。将CNMCA应用在聚酰胺6中制备了阻燃复合材料,同时,采用垂直燃烧和极限氧指数法分析了阻燃效果。结果表明,g-C3N4具有较高的热稳定性,其热失重5%(T-5%)的温度高达544.9℃。另外,g-C3N4的杂化不同程度地提高了MCA的热稳定性。当杂化比例为30%时,CNMCA的T-5%由345.5℃提升到352.3℃,在600℃下的残余质量由0.43%显著提升到23.45%。CNMCA的阻燃性能比MCA更佳,当添加到10%CNMCA30时,试样燃烧时的熔滴已无法使脱脂棉被引燃,因此,阻燃等级从UL94 V-2提升到UL94 V-0级,极限氧指数也从27.8%提升至31.3%。