共查询到17条相似文献，搜索用时 46 毫秒
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利用水热反应法将三聚氰胺悬浊液在200℃下反应生成中间产物,中间产物经煅烧直接制成了二维石墨相氮化碳(g-C3N4)纳米片(WCN),并与本体g-C3N4(CN)、传统热氧剥离法得到的g-C3N4纳米片(OCN)进行了比较.采用SEM、XRD、FTIR、Raman、AFM、PL对样品进行了表征,探讨了其光电化学性能和光催化性能.结果表明,两种方法均实现了对CN的剥离,WCN和OCN与CN的晶体结构和组成相同,WCN和OCN比表面积分别是CN的3.6倍和3.1倍.光电化学分析显示,WCN具有更好的载流子迁移与分离效率,具有较好的光催化活性.可见光照射下,WCN对亚甲基蓝(MB)的光催化降解率达到82.0％,分别是OCN和CN的2.4倍和6.7倍,光催化降解过程符合一级动力学方程.WCN具有优良的稳定性和可重复利用性能. 相似文献
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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。 相似文献
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石墨相氮化碳(g-C3 N4)作为一种多功能光催化剂,由于其具有可调节的电子能带结构和伴随2.7 eV合适带隙能量的有效光收集等优点,已逐步应用于降解水体污染物特别是有机染料.但由于体相g-C3 N4比表面积小,光生电子-空穴对复合速率快,光催化效率受到限制.因此,可以对g-C3 N4进行元素掺杂以提高其光催化降解性能.在此主要介绍了氮有效掺杂g-C3 N4,减小带隙的同时抑制电子-空穴对的快速复合,从而极大地提高了催化性能. 相似文献
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采用H2SO4与KMnO4为氧化剂,通过对热聚合法合成的原始石墨相氮化碳（g-C3N4）超声辅助氧化剥离,制备了超薄氧掺杂g-C3N4纳米片。基于HRTEM、XRD、AFM、XPS表征,考察了超声辅助氧化剥离对原始g-C3N4形貌、结构的影响;通过可见光催化降解刚果红分析了超薄氧掺杂g-C3N4纳米片的光催化性能;通过UV-vis-DRS、EIS、PL分析,探究了超薄氧掺杂g-C3N4纳米片光催化性能的增强机制。结果表明,对原始g-C3N4超声辅助氧化剥离6 h,可获得比表面积为58.45 cm2 g-1、厚度为1.08 nm的超薄氧掺杂g-C3N4纳米片;超薄氧掺杂g-C3N4纳米片（200 mg L-1）对刚果红（20 mg L-1）在120 min内可实现83%的降解,具有良好的光催化性能;与原始g-C3N4相比,超薄氧掺杂g-C3N4纳米片更有利于催化活性位点的暴露与光生载流子的分离传输,从而具有更好的光催化性能。 相似文献
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采用热聚合法,以三聚氰胺为前驱体合成类石墨相氮化碳(g-C_3N_4)光催化剂。并用同样的方法分别以掺入0. 5 wt%MgCl_2、CaCl_2、BaCl_2的三聚氰胺为前驱体合成M/g-C_3N_4(M=Mg、Ca、Ba)复合光催化剂。使用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射(UV-Vis DRS)、扫描电子显微镜(SEM)等对所制备的光催化剂进行表征。在可见光照射下,通过光催化降解亚甲基蓝(MB)溶液研究碱土金属的掺杂对g-C_3N_4光催化活性的影响。研究表明,Mg、Ca、Ba等碱土金属的掺杂对g-C_3N_4的光催化活性分别提升了5. 09、3. 66、2. 19倍。 相似文献
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段飞阳周安宁陈福欣凌洁马梦丹贾忻宇 《硅酸盐学报》2021,(10):2053-2060
通过调控前驱体三聚氰胺和尿素比例采用热聚合法得到一系列厚度可控的石墨相氮化碳(g-C_(3)N_(4))纳米片。采用X射线粉末衍射、扫描电镜、原子力显微镜、比表面积测试、紫外可见光谱和荧光光谱等手段对纳米片的结构和性能进行了表征,并探讨了其光催化降解罗丹明B(Rh B)的性能。结果表明:当三聚氰胺和尿素比例为1:8时g-C_(3)N_(4)最薄(1:8-CN),厚度仅为3.518 nm,同时1:8-CN的比表面积是以三聚氰胺为原料制备的g-C_(3)N_(4)(M-CN)的7倍。光电学分析表明,1:8-CN具有更高的光生载流子分离效率。在可见光照射下,1:8-CN对Rh B的光催化降解率可以达到96.2%,是M-CN的1.9倍。1:8-CN光催化降解Rh B的反应机理表现为:光生电子-空穴对分离产生的电子与O2结合生成·O_(2)^(-),·O_(2)^(-)将Rh B氧化生成CO2和H2O,空穴几乎不参与反应。 相似文献
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分别以尿素、三聚氰胺为前驱体,采用缩聚法制备不同形貌及性能的类石墨相氮化碳(g-C3N4)半导体催化剂,探究不同前驱体对催化剂的形貌及光催化还原CO2活性的影响。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、紫外-可见光分光光度计（Uv-vis）、傅氏转换红外线光谱分析（FTIR）、比表面积测试（BET）、荧光光谱（PL）对所得g-C3N4进行各方面性能的探究,从而分析前驱体对所得产物性能的影响。实验结果表明,以尿素为前驱体制备出的g-C3N4在甲醇溶液中光催化还原CO2制备甲酸甲酯的产率 为512.8μmol/gcat•h ,以三聚氰胺为前驱体制备出的g-C3N4光催化产率为257.3 μmol/gcat•h。 相似文献
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Yifeng Xu Bingkun Hu Jining Liu Kai Tao Ranran Wang Yang Ren Xiaofeng Zhao Jijin Xu Xuefeng Song 《Journal of the American Ceramic Society》2020,103(2):1281-1292
Microcystins (MCs) is a harmful toxin generated by blue-green algae in water, which has seriously threatened the ecological safety of water and human body. It is urgent to develop new catalysts and techniques for the degradation of MCs. A feasible electrostatic self-assembly method was carried out to synthesize BiVO4/g-C3N4 heterojunction photocatalyst with highly efficient photocatalytic ability, where BiVO4 nanoplates with exposed {010} facets anchored to the g-C3N4 ultrathin nanosheets. The morphology and microstructure of the heterojunction photocatalysts were identified by XRD, SEM, TEM, XPS, and BET. The g-C3N4 nanosheets have huge surface area over 200 m2/g and abundant mesoporous ranging from 2-20 nm, which provides tremendous contact area for BiVO4 nanoplates. Meanwhile, the introduction of BiVO4 led to red-shift of the absorption spectrum of photocatalyst, which was characterized by UV-vis diffuse reflection spectroscopy (DRS). Compared with pure BiVO4 and g-C3N4, the BiVO4/g-C3N4 heterojunction shows a drastically enhanced photocatalytic activity in degradation of microcystin-LR (MC-LR) in water. The MC-LR could be removed within 15 minutes under the optimal ratio of BiVO4/g-C3N4. The outstanding performance of the photocatalyst is attributed to synergetic effect of interface Z-scheme heterojunction and high active facets {010} of BiVO4 nanoplates, which provides an efficient transfer pathway to separate photoinduced carriers meanwhile endows the photocatalysts with strong redox ability. 相似文献
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Lingfei Liu Yisa Zhou Jian Xue Haihui Wang 《American Institute of Chemical Engineers》2019,65(10):e16699
Graphene oxide (GO) membranes have shown great potential for water purification, but their permeability and antipressure ability are poor, which limits their practical applications. In this study, two-dimensional graphitic carbon nitride (g-C3N4) nanosheet-intercalated GO (GOCN) membranes were developed to improve the separation performance of GO membranes, especially under high operating pressure. After incorporation of the g-C3N4 nanosheets, the amount of permeable nanochannels (wrinkles or corrugation) in the membrane increased; hence, the water permeance was effectively improved (twice as high as that of GO membranes). Moreover, the antipressure performance of the GOCN membranes was significantly enhanced (even below 0.5 MPa pressure) as the nanochannels in the composite membranes become stable and rigid due to the support of the pressure-resistant g-C3N4 nanosheets. The good separation performance demonstrates that the intercalation of g-C3N4 is an effective strategy to improve the GO-based membrane properties, which can promote their application in water purification. 相似文献
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Changcun Han Tong Zhang Qijun Cai Chonghao Ma Zhengfu Tong Zhifeng Liu 《Journal of the American Ceramic Society》2019,102(9):5484-5493
In this work, cobalt phosphide (CoP) nanoparticles were successfully decorated on an ultrathin g-C3N4 nanosheet photocatalysts by in situ chemical deposition. The built-in electric field formed by heterojunction interface of the CoP/g-C3N4 composite semiconductor can accelerate the transmission and separation of photogenerated charge-hole pairs and effectively improve the photocatalytic performance. TEM, HRTEM, XPS, and SPV analysis showed that CoP/g-C3N4 formed a stable heterogeneous interface and effectively enhanced photogenerated electron-hole separation. UV-vis DRS analysis showed that the composite had enhanced visible light absorption than pure g-C3N4 and was a visible light driven photocatalyst. In this process, NaH2PO2 and CoCl2 are used as the source of P and Co, and typical preparation of CoP can be completed within 3 hours. Under visible light irradiation, the optimal H2 evolution rate of 3.0 mol% CoP/g-C3N4 is about 15.1 μmol h−1. The photocatalytic activity and stability of the CoP/g-C3N4 materials were evaluated by photocatalytic decomposition of water. The intrinsic relationship between the microstructure of the composite catalyst and the photocatalytic performance was analyzed to reveal the photocatalytic reaction mechanism. 相似文献
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In photocatalytic anticorrosion perspective, the migration rate of excited electrons from surface layers to substrate steels restricted the performance of g-C3N4 due to the high resistance between interface of g-C3N4 layers and adhesive layers. Herein, an S-scheme g-C3N4/polyaniline (PANI) heterojunction with face-to-face structure was established by a secondary calcining method. The as-prepared heterojunctions were applied to protect Q235 carbon steel, and the results showed that the anticorrosion performance of S-scheme g-C3N4/PANI heterojunction is much higher than that of g-C3N4 and PANI coating layers according to salt spray test. Photocurrent intensity indicated that the optimum amounts of g-C3N4 and PANI were 0.06 and 0.09 mL/cm2, which are benefit for the transport of excited electrons due to the optimum thickness of coating layers. Furthermore, the S-scheme g-C3N4/PANI heterojunction can promote the separation rate of charge carriers and suppress the recombination rate at the same time, which are inferred from photocurrent intensity, electrochemical impedance spectra, super-depth-of-field microscope, and photoluminescence investigation. In the last, the enhanced anticorrosion performance of S-scheme g-C3N4/PANI heterojunction with face-to-face structure was deduced according to mentioned characterization. 相似文献
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一步水热法合成CuS修饰的石墨相氮化碳(g-C3N4/CuS)复合光催化剂,通过FE-SEM、XRD、FTIR、UV-Vis-DRS等手段对其进行了表征,利用Cr(VI)溶液考察了g-C3N4/CuS在可见光下的光催化还原性能.实验结果表明,g-C3N4/CuS复合光催化剂的光催化活性明显优于单一的g-C3N4和CuS.可见光照射下,180 min内Cr(VI)的去除率可达70％以上.CuS的引入不仅扩宽了g-C3N4的可见光吸收范围,而且降低了g-C3N4光生电子和空穴的复合率,从而显著提高g-C3N4的光催化活性.该复合材料的催化活性受溶液的pH值影响较大,酸性条件下更有利于光催化反应的进行;共存低浓度腐殖酸对Cr(VI)的去除没有显著影响.g-C3N4/CuS具有良好的可见光催化活性,可用于废水中Cr(VI)的光催化还原去除. 相似文献