g-C3N4及改性g-C3N4的光催化研究进展

聚合型半导体材料g-C3N4因其优异的物理性能和光电性能成为当今研究的热门材料。本文从结构分析和理论计算角度讨论了g-C3N4能够作为无金属催化剂的原因,综述了介孔g-C3N4、无机元素掺杂g-C3N4、金属负载g-C3N4、g-C3N4/金属氧化物复合物和有机改性g-C3N4等不同改性g-C3N4的制备和性质,着重分析了他们催化光解水析氢反应的机理、影响因素及研究进展,并阐述了今后的研究方向。     

g-C3N4/g-C3N4 isotype heterojunction as an efficient platform for direct photodegradation of antibiotic

A visible-light-driven g-C₃N₄/g-C₃N₄ isotype heterojunction photocatalyst was synthesized by one-step thermal treatment using urea and thiourea as the precursor. The photocatalytic activity of as-prepared photocatalyst was evaluated through the degradation of rhodamine B (RhB) and tetracycline hydrochloride (TC) under the visible light irradiation. The hybrid showed enhanced photocatalytic activity in photodegradating the applied pollutants as compared with single g-C₃N₄. When the ratio of urea to thiourea was 2:1, the prepared isotype heterojunction exhibited the highest photocatalytic activity and the photodegradation rates for RhB and TC were 99.8% and 95.1% after being visible light irradiated for 1 h and 4 h respectively. The enhanced photocatalytic performance of the isotype heterojunction is ascribed to the enhanced charge separation efficiency. After being reused for 5 times, the hybrid still showed excellent recyclability and chemical stability. Furthermore, NaI, BQ and IPA were used as the sacrificial agents for studying the surface reactions in the photocatalytic process. The method used in this work provides a new pathway to achieve more efficient degradation of antibiotics and to stimulate further studies in this important field.     

One-step synthesis of highly reactive g-C3N4

Journal of Materials Science: Materials in Electronics - Graphitic carbon nitride (g-C3N4) with well-controlled properties are the key for photocatalysis water splitting and organic pollutant...     

g-C3N4光催化性能的研究进展

利用光催化剂将太阳能转化为人类可以直接利用的能量, 并用其解决地球资源的枯竭和生存环境的恶化是可再生清洁能源研究的一个方向。g-C₃N₄的独特结构赋予其良好的光催化性能, 使之成为光催化领域的研究热点。目前在光催化领域, g-C₃N₄主要用于催化污染物分解、水解制氢制氧、有机合成及氧气还原。在实际应用中, 为进一步提高g-C₃N₄的光催化效果, 科研工作者开发了多种改进方法, 例如物理复合改性、化学掺杂改性、微观结构调整等。本文主要论述了g-C₃N₄在光催化领域的应用以及光催化性能的改进方法, 简要阐述了光催化和各种改进方法的机理, 分析了目前g-C₃N₄在光催化领域面临的问题和挑战, 展望了g-C₃N₄的应用前景。     

g-C_3N_4-CdS异质结的合成及其光催化性能研究

以尿素为前驱体,550℃热聚合反应5 h,制备了块状g-C_3N_4。然后将块状g-C_3N_4超声剥离得到片状g-C_3N_4,在g-C_3N_4纳米片上原位生长Cd S(直径约130 nm),从而制备了g-C_3N_4-Cd S异质结。g-C_3N_4-Cd S异质结的吸收边约505 nm处,与g-C_3N_4(约460 nm)相比具有明显的红移,可吸收更多的可见光。此外,g-C_3N_4-Cd S异质结可降解99%的罗丹明B,具有较高的光催化活性。     

Synthesis and photocatalytic performance of novel metal-free g-C3N4 photocatalysts

Novel metal-free g-C₃N₄ photocatalysts with light yellow colors were synthesized by heating melamine precursor at different temperatures. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectra (DRS). The effect of calcining temperatures on photocatalytic activities of g-C₃N₄ samples were investigated based on the decomposition of phenol under visible light irradiation. The DRS spectra revealed that the g-C₃N₄ had strong absorption in the visible light region. The photocatalytic results indicated that the highest phenol degradation of 92.5% was achieved on the samples heated at 520 °C for 4 h. This study may provide an approach to development of novel metal-free photocatalysts to degrade organic pollutants by using visible light.     

g-C3N4/高岭土复合材料的制备及其光催化性能研究

以水洗高岭土为载体, 采用盐酸对g-C₃N₄进行质子化处理, 通过浸渍法制备了g-C₃N₄/高岭土复合光催化材料。采用X射线衍射(XRD)、场发射扫描电镜(FESEM)和紫外-可见吸收光谱(UV-Vis)等手段对复合材料的晶体结构、微观形貌和光学性能进行了表征, 并以罗丹明B为目标降解物, 研究了复合材料在可见光下的光催化性能。结果表明: 当高岭土和g-C₃N₄的质量配比为6︰3时, g-C₃N₄/高岭土具有较优的光催化性能, 其光催化速率是纯g-C₃N₄的8.62倍; 高岭土和g-C₃N₄通过静电吸引力紧密结合在一起, 该复合结构能够有效地降低光生电子和空穴的复合几率, 改善了纯g-C₃N₄光催化材料的吸附性能, 进而有效提高了其光催化性能。     

Flower-like SnO2/g-C3N4 heterojunctions: The face-to-face contact interface and improved photocatalytic properties

Series of SnO₂/g-C₃N₄ heterojunctions with face-to-face contact have been synthesized by a two-step process. The morphology and photocatalytic property can be adjusted by tailoring the content of g-C₃N₄ in the heterostructures. The heterojunctions present flower-like morphology and vary the size of flower with the increase of the g-C₃N₄ content. The 50% SnO₂/g-C₃N₄ heterojunctions exhibit the best performances for photodegradation of rhodamine B under solar light, which is attributed to the effective interfacial contact between SnO₂ and g-C₃N₄, leading to the increased charge transfer and prolonged charge-hole separation time. Moreover, SnO₂/g-C₃N₄ heterojunctions possess excellent stability after 4 recycling runs, because the face-to-face contact interface provides a large contact area, thus forming a close combination of two phases and guaranteeing effective separation of photogenerated carriers. Furthermore, a possible photocatalytic mechanism is analyzed and it is demonstrated that the hydroxyl radical species play an important role for the photocatalytic activity. This research highlights the promising applications of SnO₂/g-C₃N₄ heterojunctions photocatalysts in the field of water purification and environmental remediation.     

改性g-C3N4掺杂聚氨酯涂层的制备及其耐腐蚀性能研究

通过硅烷偶联剂(OTS)对g-C3N4改性,将改性g-C3N4与聚氨酯共混后制备出改性g-C3N4/聚氨酯复合材料,研究不同质量分数的改性g-C3N4对改性g-C3N4/聚氨酯复合材料的耐腐蚀等性能的影响.利用红外光谱、X射线衍射能谱、X射线光电子能谱、粒径分析对g-C3N4的结构和性能进行了表征,同时利用接触角分析、...     

Photocatalytic activities of coke carbon/g-C3N4 and Bi metal/Bi mixed oxides/g-C3N4 nanohybrids for the degradation of pollutants in wastewater

Different g-C₃N₄ composite systems (coke carbon/g-C₃N₄, Bi/Bi₂WO₆/g-C₃N₄ and Bi/Bi₂MoO₆/g-C₃N₄) have been assessed as photocatalysts for wastewater pollutants removal. The coke carbon/g-C₃N₄ hybrid, produced by thermal treatment at 550 °C of a composite made from melamine cyanurate and coke, only showed activity under UV-light irradiation. On the other hand, inorganic Bi spheres/Bi mixed oxides/g-C₃N₄ nanohybrids (Bi/Bi₂WO₆/g-C₃N₄ and Bi/Bi₂MoO₆/g-C₃N₄ composites), produced by thermal reduction of Bi₂WO₆ or Bi₂MoO₆ by g-C₃N₄, exhibited a remarkable red-shift, up to 620 nm, and allowed the visible-light driven degradation of the contaminant, albeit in combination with some adsorption.     

苝四羧酸二酰亚胺修饰增强g-C_(3)N_(4)光催化性能EI北大核心CSCD

以3,4,9,10-苝四甲酸二酐和L-天冬氨酸为原料,合成水溶性苝二酰亚胺衍生物N,N′-二(2-丁二酸基)-3,4,9,10-苝四羧酸二酰亚胺(PASP)。采用水热法将PASP接枝在g-C_(3)N_(4)上,制备PASP改性g-C_(3)N_(4)复合光催化剂(g-C_(3)N_(4)-PASP)。通过X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外-可见光漫反射光谱(UV-Vis DRS)和固体荧光光谱等对g-C_(3)N_(4)-PASP的组成、结构、形貌和光学性质等进行表征,考察g-C_(3)N_(4)-PASP对水溶液中模型污染物亚甲基蓝(MB)的光催化降解活性。结果表明:g-C_(3)N_(4)与PASP经水热反应,可通过酰胺键共价结合;相比纯g-C_(3)N_(4),g-C_(3)N_(4)-PASP比表面积显著增大,吸收带边红移至614 nm,同时PASP修饰可促进g-C_(3)N_(4)材料表面光生电子和空穴分离,进而有效提升光催化活性。在可见光(λ>420 nm)照射下,g-C_(3)N_(4)-PASP对MB的降解率60 min内可达99.4%,降解速率常数k约为g-C_(3)N_(4)的2倍。     

水热法制备TiO_2/g-C_3N_4及其光催化性能

采用水热法合成了可见光响应的TiO_2/g-C_3N_4复合催化剂,通过X射线衍射(XRD)、氮气吸附-脱附(BET)法、透射电子显微镜(TEM)、紫外-可见漫反射(UV-vis DRS)、荧光光谱(PL)、X射线光电子能谱(XPS)对样品进行了表征。并以亚甲基蓝为降解对象,考察了在可见光条件下不同催化剂对亚甲基蓝的降解能力。研究结果表明,锐钛矿型二氧化钛均匀地负载在石墨相氮化碳片层上,TiO_2/g-C_3N_4复合材料的光吸收带边扩展到470nm,具有优异的可见光催化效率,它对亚甲基蓝的光催化降解率达到99.0%。     

Synthesis of porous Fe3O4/g-C3N4 nanospheres as highly efficient and recyclable photocatalysts

A facile approach for the preparation of Fe₃O₄/g-C₃N₄ nanospheres with good porous structure has been demonstrated by a hydrothermal method. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible light (UV–vis) absorbance spectra and X-ray photoelectron spectroscopy (XPS). The photocatalytic decomposition of methyl orange (MO) by the as-prepared samples was carried out under visible light irradiation. The reusability and magnetic properties were also investigated. The results revealed that the porous Fe₃O₄/g-C₃N₄ nanospheres showed considerable photocatalytic activity, and exhibited excellent reusability and magnetic properties with almost no change after five runs.