g-C_3N_4/BiOBr异质结光催化剂的制备与可见光催化活性

以三聚氰胺作为合成g-C_3N_4纳米片的前躯体,以Bi(NO3)3·5H2O和KBr作为合成BiOBr的原料,采用水热法构建g-C_3N_4/Bi OBr二维异质结可见光催化剂,有效的晶面复合和合适的能带组合有助于增强g-C_3N_4和BiOBr的可见光催化活性。利用X射线衍射(XRD)、透射电镜(TEM)、X射线光电子能谱(XPS)、光致发光光谱(PL)和紫外-可见漫反射光谱(UVvis DRS)等方法表征其结构、光学性质以及组成结构。在可见光(λ420 nm)下以光催化降解RhB来评价合成催化剂的光催化活性,结果表明,g-C_3N_4/BiOBr光催化降解罗丹明B(Rh B)的效率高于单体g-C_3N_4和BiOBr,并对g-C_3N_4/BiOBr增强可见光催化RhB机理进行解释。     

金属掺杂类石墨相氮化碳的理论研究

采用量子化学从头算密度泛函理论(DFT)计算方法,对不同金属元素掺杂的M/g-C_3N_4(M=Mn,Cu,Au)构型进行优化,分析比较这些结构的能隙大小、金属原子的结合能以及前线轨道.结果表明:M/g-C_3N_4(M=Mn,Cu,Au)的稳定性顺序为Mn/g-C_3N_4Cu/g-C_3N_4Au/g-C_3N_4;掺杂几种金属原子后M/g-C_3N_4(M=Mn,Cu,Au)的能隙明显减小,极大的增强了g-C_3N_4在可见光范围吸收能力,提高了g-C_3N_4的光催化效率.本研究对进一步理解结构修饰对g-C_3N_4光催化性能的影响提供了一定的理论支持.     

g-C3N4/CeO2异质结材料的制备及其光催化性能的研究

以三聚氰胺、硝酸铈为原料,通过高温煅烧法制备了不同CeO₂含量的片层状g-C₃N₄/CeO₂,通过XRD、FT-IR、XPS等对系列g-C₃N₄-CeO₂材料进行了表征,考察了材料在可见光(λ≥420nm)条件下降解盐酸四环素(TC)的光催化活性。与单纯的g-C₃N₄相比,g-C₃N₄/CeO₂-30%具有更优异的光催化性能,这是由于g-C₃N₄-CeO₂间的异质结作用促进了光生电子和空穴分离。自由基捕获实验证实·O^-₂在催化反应过程中起到主要作用,并提出了相应的光催化机理。     

原位聚合碳掺杂改性石墨态氮化碳光催化活性研究

本文通过在双氰胺前驱体中添加聚乙二醇,在缩聚过程实现碳掺杂形成含氮空位的g-C₃N₄光催化剂。通过X射线衍射(XRD)、红外光谱(FTIR)、光电子能谱(XPS)、紫外-可见吸收光谱(UV-Vis)和荧光谱(FL)等表征手段,考察了原位聚合碳掺杂形成氮空位对g-C₃N₄物相结构、组分与化学态、光吸收性能及光催化活性的影响。研究结果表明,采用该方法可实现原位聚合碳掺杂,有效拓展g-C₃N₄的可见光吸收至850 nm,在紫外-可见光与可见光照射下光降解RhB及光催化产氢性能均显著提高,尤其可见光条件下的性能提升更为显著。     

缺陷工程调控石墨相氮化碳及其光催化空气净化应用进展

Since the pioneering work on polychlorinated biphenyl photodegradation by Carey in 1976, photocatalytic technology has emerged as a promising and sustainable strategy to overcome the significant challenges posed by energy crisis and environmental pollution. In photocatalysis, sunlight, which is an inexhaustible source of energy, is utilized to generate strongly active species on the surface of the photocatalyst for triggering photo-redox reactions toward the successful removal of environmental pollutants, or for water splitting. The photocatalytic performance is related to the photoabsorption, photoinduced carrier separation, and redox ability of the semiconductor employed as the photocatalyst. Apart from traditional and noble metal oxide semiconductors such as P25, bismuth-based compounds, and Pt-based compounds, 2D g-C₃N₄ is now identified to have enormous potential in photocatalysis owing to the special π-π conjugated bond in its structure. However, some inherent drawbacks of the conventional g-C₃N₄, including the insufficient visible-light absorption ability, fast recombination of photogenerated electron-hole pairs, and low quantum efficiency, decrease its photocatalytic activity and limit its application. To date, various strategies such as heterojunction fabrication, special morphology design, and element doping have been adopted to tune the physicochemical properties of g-C₃N₄. Recent studies have highlighted the potential of defect engineering for boosting the light harvesting, charge separation, and adsorption efficiency of g-C₃N₄ by tailoring the local surface microstructure, electronic structure, and carrier concentration. In this review, we summarize cutting-edge achievements related to g-C₃N₄ modified with classified non-external-caused defects (carbon vacancies, nitrogen vacancies, etc.) and external-caused defects (doping and functionalization) for optimizing the photocatalytic performance in water splitting, removal of contaminants in the gas phase and wastewater, nitrogen fixation, etc. The distinctive roles of various defects in the g-C₃N₄ skeleton in the photocatalytic process are also summarized. Moreover, the practical application of 2D g-C₃N₄ in air pollution control is highlighted. Finally, the ongoing challenges and perspectives of defective g-C₃N₄ are presented. The overarching aim of this article is to provide a useful scaffold for future research and application studies on defect-modulated g-C₃N₄.      

非金属掺杂石墨相氮化碳光催化的研究进展与展望

Since Fujishima and Honda demonstrated the photoelectrochemical water splitting on TiO₂ photoanode and Pt counter electrode, photocatalysis has been considered as one of the most promising technologies for solving both the problems of environmental pollution and energy shortage. This process can effectively use solar energy, the most abundant energy resource on the earth, to drive various catalytic reactions, such as water splitting, CO₂ reduction, organic pollutant degradation, and organic synthesis, for energy generation and environmental purification. Except for the various metal-based semiconductors, such as metal oxides, metal sulfides, and metal oxynitrides, developed for photocatalysis, graphitic carbon nitride (g-C₃N₄) has attracted significant attention in the recent years because of its earth abundancy, non-toxicity, good stability, and relatively narrow band gap (2.7 eV) for visible light response. However, g-C₃N₄ suffers from insufficient absorption of visible light in the solar spectrum and rapid recombination of photogenerated electrons and holes, thus resulting in low photocatalytic activity. Until now, various strategies have been developed to enhance the photocatalytic activity of g-C₃N₄, including element doping, nanostructure and heterostructure design, and co-catalyst decoration. Among these methods, element doping has been found to be very effective for adjusting the unique electronic and molecular structures of g-C₃N₄, which could significantly expand the range of photoresponse under visible light and improve the charge separation. Especially, non-metal doping has been well investigated frequently to improve the photocatalytic activity of g-C₃N₄. The non-metal dopants commonly used for the doping of g-C₃N₄ include oxygen (O), phosphorus (P), sulfur (S), boron (B), and halogen (F, Cl, Br, I) and also carbon (C) and nitrogen (N) (for self-doping), as they are easily accessible and can be introduced into the g-C₃N₄ framework through different physical and chemical synthetic methods. In this review article, the structural and optical properties of g-C₃N₄ is introduced first, followed by a brief introduction to the modification of g-C₃N₄ as photocatalysts. Then, the progress in the non-metal doped g-C₃N₄ with improved photocatalytic activity is reviewed in detail, with the photocatalytic mechanisms presented for easy understanding of the fundamentals of photocatalysis and for guiding in the design of novel g-C₃N₄ photocatalysts. Finally, the prospects of the modification of g-C₃N₄ for further advances in photocatalysis is presented.     

铟基三元金属硫化物催化剂在光催化二氧化碳还原领域中的研究进展（英文）

化石能源的过度使用造成CO₂大量排放,导致了环境问题,同时引发了能源危机.新能源技术的快速发展为缓解上述问题提供了有效途径.光催化CO₂转化技术因绿色环保、成本低廉、反应条件温和、操作安全可控而引起了研究者们的广泛关注.推动光催化CO₂转化技术发展的关键在于高效光催化剂的精准设计与合成.目前,已经发展了多种光催化剂.铟基三元金属硫化物因具有合适的能带结构、较宽的吸光范围和独特的双金属位点而成为光催化CO₂还原领域的研究热点之一.独特的双金属结构使其具有更丰富的活性位点,同时可以调控对关键中间体的吸附和解吸,进而提高CO₂反应活性,并精准调控目标产物的选择性.然而,缓慢的电子传输行为和高载流子复合效率阻碍了CO₂还原反应效率的提升,因此,目前距离实现光催化CO₂还原技术的工业化应用仍有较大的差距.为了克服上述难题,科学家们对铟基三元金属硫化物进行了大量研究,以期通过修饰改性进一步提高催化效率和选择性.然而,目前有关铟基三元金属硫化物在光...     

石墨相氮化碳/二氧化锡复合材料的制备及光催化性能

采用热聚合法和水热法相结合的方法制备了g-C_3N_4/SnO_2复合光催化剂。利用XRD、SEM、TEM、FT-IR和UV-Vis DRS等多种测试手段对所得样品的物相结构、微观形貌和吸光特性等进行了表征。结果表明,异质结构复合光催化剂的最大光吸收边位置相对纯相SnO_2发生了明显的红移,并且SnO_2颗粒均匀分布于g-C_3N_4表面,其中最优组分(50%-g-C_3N_4/SnO_2)光催化降解染料罗丹明B(RhB)的效率达到了纯相g-C_3N_4的3.78倍。     

2D/2D BiOBr/g-C3N4 S型异质结光催化性能

近年来,能源短缺和环境污染严重威胁人类的可持续发展.光催化技术具有绿色环保、成本低等优势,被认为是解决上述问题的最佳途径之一,其实用化的核心是开发高效可见光催化材料.石墨相氮化碳(g-C3N4)因其物理化学性质稳定、无毒、廉价及能带适宜等特点,广泛应用于光催化领域.然而,光生载流子易复合、比表面积小等问题不利于其实际应...     

金属硫化物基异质结光催化剂:原理、影响、应用和原位表征（英文）

金属硫化物的窄带隙使其具有吸收可见光和红外光的优势,因此可以用于开发高效的光催化剂.同时,金属硫化物具有出色的电荷分离、较强的光还原能力和低氧化还原能垒.然而,单一金属硫化物通常具有光吸收强度不高和电子-空穴快速复合的问题.在仅考虑光吸收范围时,应选择带隙较窄的光催化剂,但其氧化还原能力较低.此外,金属硫化物易发生光腐蚀.近年来,研究发现,在两种及以上光催化剂间构建异质结可以抑制单一催化剂载流子的复合,促使电子与空穴的分离;同时,异质结光催化剂也被证实可以提高光吸收和增加反应活性位点,是解决金属硫化物自身不足的重要措施.本文总结了金属硫化物用于光催化反应的优势和缺陷,讨论了构建异质结对单一金属硫化物的影响.不同的合成方法对于异质结光催化剂的形貌结构及性能具有重要影响,列举了一些金属硫化物异质结合成方法实例,例如水热合成法、离子交换法、静电纺丝法和原位光化学沉积法等.异质结光催化剂的种类可以根据电子转移机理分为肖特基结、type Ⅱ型、Z型和S型异质结等.随后,概述了金属硫化物异质结在环境和能源领域的应用,比较了不同类型金属硫化物异质结的光催化活性.充分利用光生电子和空穴分别驱动氧化和还...     

高效可见光响应Zn_(0.11)Sn_(0.12)Cd_(0.84)S_(1.12)/g-C_3N_4异质结光催化剂的制备及性能

以双氰胺、醋酸锌、四氯化锡、醋酸镉和硫化钠为原料,采用水热法制备了三元金属复合硫化物Zn_(0.11)Sn_(0.12)Cd_(0.84)S_(1.12)(ZnSnCdS)及一系列异质结催化剂ZnSnCdS/g-C_3N_4.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外-可见光谱仪(UV-Vis)、傅里叶变换红外光谱仪(FTIR)、电感耦合等离子体-质谱仪(ICP-MS)、荧光光谱仪(PL)和X射线光电子能谱仪(XPS)等对催化剂进行了表征.结果表明,ZnSnCdS与g-C_3N_4之间以C—S键紧密结合,构筑了异质结,促进了界面电荷迁移,抑制了光生电子-空穴对的复合.可见光下降解染料罗丹明B(RhB)的结果表明,ZnSnCdS/g-C_3N_4异质结催化剂的光催化性能与单纯g-C_3N_4,ZnSnCdS及双组分硫化物/g-C3N4异质结催化剂相比均有大幅度提高,ZnSnCdS与g-C3N4质量比为4∶1时异质结催化剂表现出最大的速率常数(0.1508 min-1),是单纯g-C_3N_4和ZnSnCdS的32.3倍和4.9倍.其它三元金属复合硫化物如ZnMoCdS,MoNiCdS和NiSnCdS与g-C_3N_4之间也能有效形成异质结,促进电子-空穴对的分离和催化性能的提升.     

In situ Carbon Modification of g-C3N4 from Urea co-Crystal with Enhanced Photocatalytic Activity Towards Degradation of Organic Dyes Under Visible Light

An in situ strategy was introduced for synthesizing carbon modified graphitic carbon nitride(g-C₃N₄) by using urea/4-aminobenzoic acid(PABA) co-crystal(PABA@Urea) as precursor materials. Via co-calcination of the PABA co-former and the urea in PABA@Urea co-crystals, C guest species were generated and compounded into g-C₃N₄ matrix in situ by replacing the lattice N of the carbon nitride and forming carbon dots onto its layer surface. The carbon modification dramatically enhanced visible-light harvesting and charge carrier separation. Therefore, visible light photo-catalytic oxidation of methylene blue(MB) pollution in water over the carbon modified g-C₃N₄(C/g-C₃N₄) was notably improved. Up to 99% of methylene blue(MB) was eliminated within 60 min by the optimal sample prepared from the PABA@Urea co-crystal with a PABA content of 0.1%(mass ratio), faster than the degradation rate over bare g-C₃N₄. The present study demonstrates a new way to boost up the photocatalysis performance of g-C₃N₄, which holds great potential concerning the degradation of organic dyes from water.     

石墨相氮化碳/蒙脱石复合材料的制备及其可见光催化性能

为提高石墨相氮化碳(g-C₃N₄)对可见光的利用率及光催化效率,采用热聚合与直接负载等方法,将g-C₃N₄负载于蒙脱石表面,制备了g-C₃N₄/蒙脱石复合光催化材料,其结构经SEM, FT-IR及XRD表征。以罗丹明B(RhB)为目标污染物,研究了不同负载量g-C₃N₄/蒙脱石复合光催化剂的可见光催化性能。并分别以对苯醌、碘化钾和异丙醇为自由基捕获剂,研究了复合材料的光催化机理。结果表明：当g-C₃N₄的质量分数为83%(CN/M-83%)时,RhB经可见光照射1 h后,降解率达到99.2%。光催化速率常数为纯g-C₃N₄光催化速率常数的3.2倍。     

g-C_3N_4/CdS纳米棒复合光催化剂的制备及其光催化性能

采用简单的水热法制得CdS纳米棒,采用溶剂热法制得g-C_3N_4/CdS纳米棒复合光催化剂(1),其结构和性能经SEM,XRD和UV-Vis(DRS)表征。探究了1在可见光作用下光催化降解模拟有机污染物甲基橙的性能。结果表明:在可见光作用下,与纯CdS纳米棒光催化剂比较,1的催化活性明显提高,稳定性显著增强。     

g-C3N4/BiVO4复合催化剂的制备及应用于光催化还原CO2的性能

用简单的超声分散法合成了具有可见光响应的类石墨氮化碳(g-C₃N₄)/BiVO₄复合光催化剂. 采用X射线衍射(XRD), X射线光电子能谱(XPS), 扫描电子显微镜(SEM), 透射电子显微镜(TEM), 紫外-可见(UV-Vis)分光光谱, 傅里叶红外变换(FTIR)光谱, 荧光发射谱(PL)和光电流响应等技术对所制备催化剂进行相关表征. 通过可见光下(λ> 420 nm)光催化还原CO₂的性能来评价样品的光催化活性, 发现不同复合比的催化剂中, 含40% (w) g-C₃N₄的复合催化剂表现出最高的光催化活性, 其催化活性分别为纯g-C₃N₄纳米片和纯BiVO₄的催化活性的2倍和4倍.光催化活性增加的主要原因是g-C₃N₄和BiVO₄之间形成了异质结, 且相互间能级匹配, 有利于光生电子和空穴的分离.     

二氧化钛涂覆多壁碳纳米管的制备及可见光催化活性

以多壁碳纳米管(MWCNTs)为反应性模板, 金属钛粉为钛源, 采用熔盐法制备碳化钛涂覆的MWCNTs中间体, 然后通过控制氧化制备二氧化钛涂覆的MWCNTs复合光催化剂. 考察了熔盐反应温度、MWCNTs和钛粉的摩尔比及氧化温度等对产物的结构和形貌的影响. 采用X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等技术对其进行了系统的表征; 以亚甲基蓝(MB)溶液的脱色降解为模型反应, 考察了催化剂的可见光(λ>420 nm)催化活性. 结果表明: 所制备的催化剂基本保持了原始MWCNTs的纤维状形貌, 二氧化钛涂层在MWCNTs表面分布均匀, 并与MWCNTs之间结合紧密, 形成了Ti－O－C键. MWCNTs增强了污染物亚甲基蓝在催化剂表面的吸附, Ti－O－C键的形成使得在二氧化钛价带附近形成了杂质能级, 提高了对可见光的吸收和利用, 因此所制备的TiO₂/MWCNTs复合光催化剂表现出较高的可见光催化活性.     

p-n异质结型光催化剂BiOBr/NaBiO3的制备与可见光催化活性

采用化学蚀刻法在NaBiO3表面利用HBr与NaBiO3的反应原位沉积BiOBr,制备了异质结型光催化剂.利用X射线粉末衍射仪(XRD)、紫外-可见漫反射光谱仪(UV-Vis DRS)和扫描电子显微镜(SEM)等对其相结构、微观形貌和光吸收性能进行了表征.光催化实验结果表明,BiOBr/NaBiO3在可见光下可以有效降解罗丹明B(RhB)溶液,当BiOBr与NaBiO3的摩尔比为40.1%时,BiOBr/NaBiO3具有最大催化活性.通过不同牺牲剂的加入及荧光实验结果推测了该异质结型材料光催化过程中光生载流子的传输方向及活性物种.研究结果表明,BiOBr/NaBiO3催化活性的增强主要归结为两者之间形成了有效的异质结,其内建电场能够促进光生载流子的分离,同时h+在光催化降解过程中是主要的活性物种.     

Hydrothermal Synthesis of Ce-doped ZnO Heterojunction Supported on Carbon Nanofibers with High Visible Light Photocatalytic Activity

Ce/ZnO decorated carbon nanofibers(CNFs) heteroarchitectures(Ce/ZnO/CNFs) have been synthesized using electrospinning technique followed hydrothermal method, which have a high visible light photocatalytic activity. The samples were characterized by means of SEM, FTIR and XRD. The photocatalytic performance of Ce/ZnO/CNFs was tested with the methylene blue in the presence of visible light irradiation. In this work, we have analyzed the effects of Ce doping amount, initial methylene blue(MB) concentration and dosage of Ce/ZnO/CNFs on photocatalytic efficiency of the composite. The results showed that the photocatalyst containing 1.0% Ce in molarity(CZC1) obtained by autoclaving at 150℃ has the best photocatalytic degradation of MB than other as-synthesized samples. Ce/ZnO/CNFs catalysts exhibit a good stability and reusability, which would be an economical and environmentally friendly photocatalyst for various practical applications.     

Photocatalytic activity under visible light illumination of organic dyes over g-C3N4/MgAl2O4 nanocomposite

Using a grinding method, nanocomposites of graphitic carbon nitride (g-C₃N₄) and magnesium aluminate (MgAl₂O₄) spinel were successfully synthesized for the photocatalytic degradation of methylene blue (MB) and methyl orange (MO). Variously formulated g-C₃N₄/MgAl₂O₄ nanocomposites were characterized by thermal gravimetric analysis (TGA), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy equipped with energy dispersive spectroscopy (SEM/EDS), transmission electron microscopy (TEM) and surface area and micropore analysis (BET surface area). The g-C₃N₄ powder exhibited a nanosheet structure whereas the MgAl₂O₄ spinel comprised agglomerated nanoparticles. The optical properties of the g-C₃N₄/MgAl₂O₄ nanocomposites were investigated by diffuse reflectance spectroscopy (DRS). As the g-C₃N₄ loading content increased from 0 to 30%, the optical band gap energy of the nanocomposite decreased from 3.84 to 2.86 eV, the specific surface area decreased from 153.78 to 114.45 m²/g, and the porosity decreased from 0.447 to 0.347 cm³/g. A 20%g-C₃N₄/MgAl₂O₄ nanocomposite proved to be the most effective photocatalyst and degraded MB faster and more completely than MO. The degradation rates of both MO (0.0107 min^?1) and MB (0.0386 min^?1) in a mixed MO-MB system were greater than the degradation rates in their single systems. The key factor that improved the photocatalytic degradation of MO was the synergistic effect whereas the synergistic effect and photosensitization were the key factors that enhanced the photocatalytic degradation of MB. The g-C₃N₄/MgAl₂O₄ nanocomposite is suitable for the photocatalytic degradation of mixed dyes because its point of zero charge is neutral and it is stable and recyclable.     

可见光下高催化活性不同结构Sr/TiO2催化剂的制备和表征

采用分步沉积法制备不同Sr/Ti 摩尔比例的Sr/TiO₂催化剂, 以X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、傅里叶变换红外(FT-IR) 光谱、紫外-可见漫反射光谱(UV-Vis RDS)等手段对样品进行了表征, 以可见光催化降解亚甲基蓝为模型反应考察样品光催化活性. 结果表明, 催化剂的活性和结构随Sr/Ti 摩尔比(n(Sr)/n(Ti))的变化而变化, 当n(Sr)/n(Ti)≤3/2 时, 催化剂呈由TiO₂和SrTiO₃组成的球状结构; 而当n(Sr)/n(Ti)在3/2 与4/1 之间时, 催化剂呈片状结构, 且随着n(Sr)/n(Ti)增大, 催化剂组成由SrTiO₃ 和Sr₂₄ 变为Sr₂₄和Sr(OH)₂·H₂O; 当n(Sr)/n(Ti)=9/1 时, 催化剂呈以Sr(OH)₂·H₂O为主的针状结构. 其中, n(Sr)/n(Ti)=4/1的样品表现出最高的光催化活性, 一级反应速率为SrTiO₃钙钛矿催化剂的5.0倍, 商用P25的86.7倍.