In-situ Construction of Sulfur-doped g-C3N4/defective g-C3N4 Iso-type Step-scheme Heterojunction for Boosting Photocatalytic H2 Evolution

The rational construction of a high-efficiency stepscheme heterojunctions is an effective strategy to accelerate the photocatalytic H₂.Unfortunately,the variant energy-level matching between two different semiconductor confers limited the photocatalytic performance.Herein,a newfangled graphitic-carbon nitride(g-C₃N₄)based isotype step-scheme heterojunction,which consists of sulfur-doped and defective active sites in one microstructural unit,is successfully developed by in-situ polymerizing N,N-dimethylformamide(DMF)and urea,accompanied by sulfur(S)powder.Therein,the polymerization between the amino groups of DMF and the amide group of urea endows the formation of rich defects.The propulsive integration of S-dopants contributes to the excellent fluffiness and dispersibility of lamellar g-C₃N₄.Moreover,the developed heterojunction exhibits a significantly enlarged surface area,thus leading to the more exposed catalytically active sites.Most importantly,the simultaneous introduction of S-doping and defects in the units of g-C₃N₄ also results in a significant improvement in the separation,transfer and recombination efficiency of photo-excited electron-hole pairs.Therefore,the resulting isotype step-scheme heterojunction possesses a superior photocatalytic H₂ evolution activity in comparison with pristine g-C₃N₄.The newly afforded metal-free isotype step-scheme heterojunction in this work will supply a new insight into coupling strategies of heteroatoms doping and defect engineering for various photocatalytic systems.     

水分子在均三嗪基g-C3N4上的吸附

气体分子与光催化剂之间的相互作用对于光催化反应的触发非常重要.对于TiO2,ZnO和WO3等传统金属氧化物光催化剂上的水分解反应而言,已有许多报道研究了水分子在它们表面的吸附行为.结果表明,水分子与催化剂表面的原子形成了O-H…O氢键.石墨相氮化碳(g-C3N4)是一种具有可见光响应且化学性质稳定的光催化剂,对其进行修饰以增强其分解水产氢性能的研究非常多.本文通过密度泛函理论计算,全面研究了水分子在均三嗪(s-triazine)基g-C3N4上的吸附情况.首先构建了一系列初始吸附模型,考察了各种吸附位和水分子的朝向.通过比较分析计算得到的吸附能,确定了一种最优的吸附构型,即水分子以竖直的朝向吸附于褶皱的单层g-C3N4表面.水分子中的一个极性O-H键与g-C3N4中一个二配位富电子的氮原子结合形成了分子间的O-H…N氢键.其中,H原子与N原子的间距为1.92?,O-H键的键长由0.976?增至0.994?.进一步通过计算Mulliken电荷,态密度和静电势曲线分析了该吸附体系的电子性质.结果发现在分子间氢键的桥接作用下,g-C3N4上的电子转移至水分子,由此导致g-C3N4的费米能级降低,功函数由4.21 eV增至5.30 eV.在该吸附模型的基础上,考查了不同的吸附距离.当水分子与g-C3N4的间距设为1至4?时,几何优化后总是能得到相同的吸附构型,吸附能和氢键长度也十分相近.随后,通过改变吸附基底g-C3N4的大小和形状,验证了这种吸附构型具有很强的重复性.将2′2单层g-C3N4吸附基底替换为2′2多层g-C3N4(2至5层),3′3和4′4单层g-C3N4,以及具有不同管径的单壁g-C3N4纳米管后,水分子的吸附能随着体系原子数的增多而增大,但吸附模型的几何结构和电子性质基本不变,包括O-H…N氢键的形成和键长,以及电子转移和增大的功函数.另外还研究了非金属元素(P,O,S,Se,F,Cl和Br)掺杂对吸附能的影响.构建模型时,杂质原子以取代二配位氮原子的方式进行掺杂,水分子放置于杂质原子上方.结果显示,引入杂质原子后水分子的吸附能增大,在理论上从吸附的角度解释了元素掺杂增强g-C3N4分解水活性.总之,本文揭示了一种在分子间氢键的作用下,具有高取向性的水分子吸附的g-C3N4构型,这有助于g-C3N4基光催化剂上水分解过程的理解和优化设计.     

Hydrocarbon production by addition of Cu-ZnO on g-C3N4 for CO2 conversion

In this study, copper/zinc oxide/graphite nitrogen carbide (Cu/ZnO/g-C₃N₄) is prepared using a hydrothermal method and applied as a photocatalyst for CO₂ photoreduction. The morphology and structural properties of the obtained Cu/ZnO/g-C₃N₄ are systematically characterized through X-ray powder diffraction, ultraviolet–visible absorption spectroscopy, transmission electronic microscopy, and photoluminescence spectroscopy. A 3 wt% Cu/ZnO/g-C₃N₄ photocatalyst exhibits high CH₄ (40.7 μmol g⁻¹ hr⁻¹), CO (65.1 μmol g⁻¹ hr⁻¹), and CH₃OH (92.5 μmol g⁻¹ hr⁻¹) production rates, which are 38.3, 77.1, and 58.1 fold higher than the pure g-C₃N₄. The production rate is higher than those for bulk g-C₃N₄ and ZnO/g-C₃N₄. Finally, the reaction mechanism of Cu/ZnO/C₃N₄ is proposed in this study.     

Self-assembled g-C3N4 nanosheets with Ca2+ linkage

Russian Journal of Physical Chemistry A - Graphitic carbon nitride nanosheets (g-C3N4 NS) are an important material with many promising practical applications. However, construction of g-C3N4 NS...     

MxCo3O4/g-C3N4 Derived from Bimetallic MOFs/g-C3N4 Composites for Styrene Epoxidation by Synergistic Photothermal Catalysis

Although metal-organic frameworks(MOFs) have been widely reported as precursors for obtaining various porous materials in recent years, the limited MOF types and monofunctional active site of MOF-based catalysts remain to be hard to crack. Herein, bimetallic MOFs, MCo-ZIFs stabilized by graphitized carbon nitride(g-C₃N₄) and their pyrolytic M_xCo₃O₄/g-C₃N₄ hybrids(M=Zn, Cu, Fe, Ni) have been designedly synthesized. The obtained M_xCo₃O₄/g-C₃N₄ hybrids display synergistic photothermal effect from both M_xCo₃O₄ and g-C₃N₄ under visible light irradiation. Significantly, the solution temperature can be heated from room temperature(20℃) to 66℃ after 40 min irradiation. Therefore, the catalytic activity of M_xCo₃O₄/g-C₃N₄ exceeds those of most reported catalysts under mild reaction conditions. The optimal Zn_xCo₃O₄/g-C₃N₄ catalyst realizes 96% conversion and 75% selectivity toward styrene oxide within 20 min. Incredibly, the Cu_xCo₃O₄/g-C₃N₄ could achieve up to 89% selectivity toward styrene oxide. To our knowledge, this is the first report about the novel photothermal effect of ZIFs-derived metal oxides.     

利用硫化铋纳米颗粒增强类石墨相氮化碳的光生载流子分离效率和光催化活性（英文）

二氧化钛,氧化锌,磷酸铋等传统的紫外光响应光催化剂虽然具有良好的光催化性能,但是对太阳能利用率很低(紫外光只占太阳光能量的4%左右).近年来,类石墨相氮化碳(g-C3N4)受到了广泛的关注.g-C3N4的带隙约2.7 eV,它只能吸收460nm以下的光,对太阳能的利用率依然比较低.构筑异质结是一种有效的提高光催化活性的方法.BiOCl/g-C3N4,TiO2/g-C3N4, Bi2MoO6/g-C3N4, Al2O3/g-C3N4, Ag3PO4/g-C3N4等异质结光催化剂曾被广泛的报道.硫化铋是属于正交晶系的窄带隙半导体,它的带隙约1.3–1.7 e V.由于其独特的电子结构和光学特性,硫化铋在光催化,光检测器和医药成像等领域有着广泛的应用.另外,硫化铋还具有优异的光热转换性能,在光热癌症治疗领域有显著的效果.微波辅助法,水热法,惰性气体下高温煅烧法等都曾被用来合成g-C3N4/Bi2S3异质结光催化剂.不同的文献也提出了不同的催化机理.如何使用更简单环保的方法来合成g-C3N4/Bi2S3异质结光催化剂?电子和空穴的转移路径是怎样的?本文利用简单的低温方法合成了硫化铋,利用超声法得到了g-C3N4/Bi2S3异质结光催化剂,分析了其微观形貌,结构,并探讨了光催化的反应机理和提高光催化性能的因素.X射线衍射,傅里叶变换红外光谱, X射线光电子能谱和透射电子显微镜的结果表明,硫化铋纳米颗粒被成功地引入到g-C3N4中.使用亚甲基蓝为分子探针研究了所制材料在模拟太阳光下的光催化活性.结果发现, CN-BiS-2表现出最佳的光催化活性,是g-C3N4的2.05倍,是Bi2S3的4.42倍.利用液相色谱二级质谱联用分析了亚甲基蓝的降解路径.硫化铋的引入拓展了复合材料的吸收边,使其向可见光区红移,且在整个可见光区的光吸收能力都有明显的增强.光电流的增强和交流阻抗谱圆弧半径的减小,表明光生载流子的迁移与分离速率得到了增强.自由基捕获试验表明,最主要的活性物种是光生空穴,次之是羟基自由基和超氧自由基.在CN-Bi S-2样品中羟基自由基和超氧自由基的电子顺磁共振信号都比g-C3N4有明显的增强,表明复合样品中能够产生更多的羟基自由基和超氧自由基.基于光电流,交流阻抗,荧光光谱,自由基捕获和电子顺磁共振的结果,我们提出了高能电子由硫化铋转移到g-C3N4,同时空穴由g-C3N4转移到硫化铋的电子空穴转移机制.此外,红外热成像的结果表明, g-C3N4/Bi2S3异质结材料具有更强的光热转换能力,从而有利于加速光生载流子分离.     

g-C3N4 quantum dots-modified mesoporous TiO2–SiO2 for enhanced photocatalysis

Research on Chemical Intermediates - The utilization of TiO2-based photocatalysts for an efficient removal of dye pollutants is limited due to their low surface area, high recombination rate of the...     

Cu2+改性g-C3N4光催化剂的光催化性能

Photocatalytic technology can effectively solve the problem of increasingly serious water pollution, the core of which is the design and synthesis of highly efficient photocatalytic materials. Semiconductor photocatalysts are currently the most widely used photocatalysts. Among these is graphitic carbon nitride (g-C₃N₄), which has great potential in environment management and the development of new energy owing to its low cost, easy availability, unique band structure, and good thermal stability. However, the photocatalytic activity of g-C₃N₄ remains low because of problems such as wide bandgap, weakly absorb visible light, and the high recombination rate of photogenerated carriers. Among various modification strategies, doping modification is an effective and simple method used to improve the photocatalytic performance of materials. In this work, Cu/g-C₃N₄ photocatalysts were successfully prepared by incorporating Cu²⁺ into g-C₃N₄ to further optimize photocatalytic performance. At the same time, the structure, morphology, and optical and photoelectric properties of Cu/g-C₃N₄ photocatalysts were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy (DRS), and photoelectric tests. XRD and XPS were used to ensure that the prepared photocatalysts were Cu/g-C₃N₄ and the valence state of Cu was in the form of Cu²⁺. Under visible light irradiation, the photocatalytic activity of Cu/g-C₃N₄ and pure g-C₃N₄ photocatalysts were investigated in terms of the degradation of RhB and CIP by comparing the amount of introduced copper ions. The experimental results showed that the degradation ability of Cu/g-C₃N₄ photocatalysts was stronger than that of pure g-C₃N₄. The N₂ adsorption-desorption isotherms of g-C₃N₄ and Cu/g-C₃N₄ demonstrated that the introduction of copper had little effect on the microstructure of g-C₃N₄. The small difference in specific surface area indicates that the enhanced photocatalytic activity may be attributed to the effective separation of photogenerated carriers. Therefore, the enhanced photocatalytic degradation of RhB and CIP over Cu/g-C₃N₄ may be due to the reduction of carrier recombination rate by copper. The photoelectric test showed that the incorporation of Cu²⁺ into g-C₃N₄ could reduce the electron-hole recombination rate of g-C₃N₄ and accelerate the separation of electron-hole pairs, thus enhancing the photocatalytic activity of Cu/g-C₃N₄. Free radical trapping experiments and electron spin resonance indicated that the synergistic effect of superoxide radicals (O₂^•−), hydroxyl radicals (•OH) and holes could increase the photocatalytic activity of Cu/g-C₃N₄ materials.     

Enhanced photocatalytic H2 production over dual-cocatalyst-modified g-C3N4 heterojunctions

Ag nanoparticles (NPs) were deposited on the surface of g-C₃N₄ (CN) by an in situ calcination method. NiS was successfully loaded onto the composites by a hydrothermal method. The results showed that the 10 wt%-NiS/1.0 wt%-Ag/CN composite exhibits excellent photocatalytic H₂ generation performance under solar-light irradiation. An H₂ production rate of 9.728 mmol·g^?1·h^?1 was achieved, which is 10.82-, 3.45-, and 2.77-times higher than those of pure g-C₃N₄, 10 wt%-NiS/CN, and 1.0 wt%-Ag/CN composites, respectively. This enhanced photocatalytic H₂ generation can be ascribed to the co-decoration of Ag and NiS on the surface of g-C₃N₄, which efficiently improves light harvesting capacity, photogenerated charge carrier separation, and photocatalytic H₂ production kinetics. Thus, this study demonstrates an effective strategy for constructing excellent g-C₃N₄-related composite photocatalysts for H₂ production by using different co-catalysts.     

Two-dimensional g-C3N4 nanosheets-based photo-catalysts for typical sustainable processes

Graphitic carbon nitride (g-C₃N₄) has been widely studied as a visible light responsive photocatalyst in recent years, due to its facile synthesis, low cost, high stability, and appropriate bandgap/band positions. In this review, we firstly introduce and compare various exfoliation approaches of bulk g-C₃N₄ into ultrathin g-C₃N₄ nanosheets. Then, many modification strategies of g-C₃N₄ nanosheets are also reviewed, including heterojunction construction, doping, defect control, and structure design. Thereafter, the charge transfer mechanism in g-C₃N₄ nanosheets based heterojunctions is present, e.g., Z-scheme, S-scheme and other forms. Besides, the photocatalytic applications of g-C₃N₄ nanosheets based photocatalysts are summarized including environmental remediation, energy generation and storage, organic synthesis, and disinfection. This review ends with a summary and some perspectives on the challenges and new directions in exploring g-C₃N₄ nanosheets-based photocatalysts.     

Surface-engineering strategies for g-C3N4 as efficient visible-light photocatalyst

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Preparation of NiCoP-decorated g-C3N4 as an efficient photocatalyst for H2O2 production

Research on Chemical Intermediates - The development of high-efficiency economic photocatalyst for H2O2 production is of great significance for renewable energy technologies. Here, we use a...     

Photocatalytic Stille Cross-coupling on Gold/g-C3N4Nano-heterojunction

Heterogeneous catalysts have been developed for C-C coupling reactions, but stand low activity and always proceed under harsh conditions. Photocatalytic Stille cross-coupling reaction as a green catalytic method for C-C bond formation is of great interest for a wide range of scientists but still lacks stable and highly efficient catalysts. Herein, we have designed an Au nanoparticle-graphitic carbon nitride heterojunction as an outstanding photocatalyst for artificial photosynthesis in Stille cross-coupling reaction. The interface effect between metal and semiconductor makes electron rectify and prevents the recombination of electron-hole pairs. Moreover, the efficiency of Au nanoparticle catalysts could be adjusted by gold contents. Thus the turnover frequency(TOF) value reached the highest level of 788 h^-1 over the optimal heterojunction catalyst. Most importantly, the C-C bond formation reaction has been proved to be carried out well under visible light irradiation, indicating the low-cost organic synthesis process. Further analysis confirmed the stability and general application of our heterogeneous Au nano-heterojunction catalyst.     

基于g-C3N4的Z型光催化体系研究进展

导电聚合物型光催化材料g-C₃N₄有着独特的电子结构、稳定的化学性能和显著的可见光催化活性。基于g-C₃N₄的Z型光催化体系(Z-g-C₃N₄)的催化效率高、电子-空穴复合率低而备受关注,在光催化领域展现出了巨大的应用潜力。本文阐述了Z-g-C₃N₄型光催化反应体系的作用机理,综述了Z-g-C₃N₄在光催化领域的研究进展,介绍了Z-g-C₃N₄在产氢、转化CO₂、降解有机物等光催化领域的应用,讨论了pH值、导电介质等因素对Z-g-C₃N₄光催化性能的影响。最后指出了Z-g-C₃N₄光催化体系在研究过程中面临的问题和研究方向。     

Controllable design of Zn-Ni-P on g-C3N4 for efficient photocatalytic hydrogen production

Synthesizing a stable and efficient photocatalyst has been the most important research goal up to now. Owing to the dominant performance of g-C₃N₄ (graphitized carbonitride), an ordered assemble of a composite photocatalyst, Zn-Ni-P@g-C₃N₄, was successfully designed and controllably prepared for highly efficient photocatalytic H₂ evolution. The electron transport routes were successfully adjusted and the H₂ evolution was greatly improved. The maximum amount of H₂ evolved reached about 531.2 μmol for 5 h over Zn-Ni-P@g-C₃N₄ photocatalyst with a molar ratio of Zn to Ni of 1:3 under illumination of 5 W LED white light (wavelength 420 nm). The H₂ evolution rate was 54.7 times higher than that over pure g-C₃N₄. Moreover, no obvious reduction in the photocatalytic activity was observed even after 4 cycles of H₂ production for 5 h. This synergistically increased effect was confirmed through the results of characterizations such as XRD, TEM, SEM, XPS, N₂ adsorption, UV-vis DRS, transient photocurrent, FT-IR, transient fluorescence, and Mott-Schottky studies. These studies showed that the Zn-Ni-P nanoparticles modified on g-C₃N₄ provide more active sites and improve the efficiency of photogenerated charge separation. In addition, the possible mechanism of photocatalytic H₂ production is proposed.     

二维/二维FeNi-LDH/g-C3N4复合光催化剂用于促进CO2光还原反应

Photocatalytic reduction of carbon dioxide into chemical fuels is a promising route to generate renewable energy and curtail the greenhouse effect. Therefore, various photocatalysts have been intensively studied for this purpose. Among them, g-C₃N₄, a 2D metal-free semiconductor, has been a promising photocatalyst because of its unique properties, such as high chemical stability, suitable electronic structure, and facile preparation. However, pristine g-C₃N₄ suffers from low solar energy conversion efficiency, owing to its small specific surface area and extensive charge recombination. Therefore, designing g-C₃N₄ (CN) nanosheets with a large specific surface area is an effective strategy for enhancing the CO₂ reduction performance. Unfortunately, the performance of CN nanosheets remains moderate due to the aforementioned charge recombination. To counter this issue, loading a cocatalyst (especially a two-dimensional (2D) one) can enable effective electron migration and suppress electron-hole recombination during photo-irradiation. Herein, CN nanosheets with a large specific surface area (97 m²·g^-1) were synthesized by a two-step calcination method, using urea as the precursor. Following this, a 2D/2D FeNi-LDH/g-C₃N₄ hybrid photocatalyst was obtained by loading a FeNi layered double hydroxide (FeNi-LDH) cocatalyst onto CN nanosheets by a simple hydrothermal method. It was found that the production rate of methanol from photocatalytic CO₂ reduction over the FeNi-LDH/g-C₃N₄ composite is significantly higher than that of pristine CN. Following a series of characterization and analysis, it was demonstrated that the FeNi-LDH/g-C₃N₄ composite photocatalyst exhibited enhanced photo-absorption, which was ascribed to the excellent light absorption ability of FeNi-LDH. The CO₂ adsorption capacity of the FeNi-LDH/g-C₃N₄ hybrid photocatalyst improved, owing to the large specific surface area and alkaline nature of FeNi-LDH. More importantly, the introduction of FeNi-LDH on the CN nanosheet surface led to the formation of a 2D/2D heterojunction with a large contact area at the interface, which could promote the interfacial separation of charge carriers and effectively inhibit the recombination of the photogenerated electrons and holes. This subsequently resulted in the enhancement of the CO₂ photo-reduction activity. In addition, by altering the loading amount of FeNi-LDH for photocatalytic performance evaluation, it was found that the optimal loading amount was 4% (w, mass fraction), with a methanol production rate of 1.64 μmol·h^-1·g^-1 (approximately 6 times that of pure CN). This study provides an effective strategy to improve the photocatalytic CO₂ reduction activity of g-C₃N₄ by employing 2D layered double hydroxide as the cocatalyst. It also proposes a protocol for the successful design of 2D/2D photocatalysts for solar energy conversion.      

Different Dimensionalities,Morphological Advancements and Engineering of g-C3N4-Based Nanomaterials for Energy Conversion and Storage

Graphitic carbon nitride (g-C₃N₄) has gained tremendous interest in the sector of power transformation and retention, because of its distinctive stacked composition, adjustable electronic structure, metal-free feature, superior thermodynamic durability, and simple availability. Furthermore, the restricted illumination and extensive recombination of photoexcitation electrons have inhibited the photocatalytic performance of pure g-C₃N₄. The dimensions of g-C₃N₄ may impact the field of electronics confinement; as a consequence, g-C₃N₄ with varying dimensions shows unique features, making it appropriate for a number of fascinating uses. Even if there are several evaluations emphasizing on the fabrication methods and deployments of g-C₃N₄, there is certainly an insufficiency of a full overview, that exhaustively depicts the synthesis and composition of diverse aspects of g-C₃N₄. Consequently, from the standpoint of numerical simulations and experimentation, several legitimate methodologies were employed to deliberately develop the photocatalyst and improve the optimal result, including elements loading, defects designing, morphological adjustment, and semiconductors interfacing. Herein, this evaluation initially discusses different dimensions, the physicochemical features, modifications and interfaces design development of g-C₃N₄. Emphasis is given to the practical design and development of g-C₃N₄ for the various power transformation and inventory applications, such as photocatalytic H₂ evolution, photoreduction of CO₂ source, electrocatalytic H₂ evolution, O₂ evolution, O₂ reduction, alkali-metal battery cells, lithium-ion batteries, lithium–sulfur batteries, and metal-air batteries. Ultimately, the current challenges and potential of g-C₃N₄ for fuel transformation and retention activities are explored.     

二维纳米材料g-C3N4在电化学发光中的应用研究

电化学发光(ECL)兼备电化学和化学发光的特点,灵敏度高、线性范围宽、背景干扰小,得到了广大分析科学研究者的关注;传统的ECL材料虽然发光效率高,但仍存在价格昂贵、负载量低等缺点。g-C₃N₄是一种不含金属的半导体纳米材料,主要以三嗪环或七嗪环为基本结构单元,通过层间的范德华力以及层内的C—N共价键结合,构成类石墨的二维层状结构,具有性质稳定、能带结构独特、生物兼容性好、环保无毒、易于功能化、原料价廉、制备过程简单等优点。自2012年g-C₃N₄首次被发现具备ECL的性能,至今已被广泛应用到ECL中。本文根据ECL的发光机理、传感器的作用效果、传感的信号类型以及不同的检测对象进行了分类,综述了近年来g-C₃N₄在ECL传感器构建中的研究进展,并阐述了g-C₃N₄在ECL发展中存在的挑战和前景。     

Surface Engineering of g-C3N4 by Stacked BiOBr Sheets Rich in Oxygen Vacancies for Boosting Photocatalytic Performance

BiOBr containing surface oxygen vacancies (OVs) was prepared by a simple solvothermal method and combined with graphitic carbon nitride (g-C₃N₄) to construct a heterojunction for photocatalytic oxidation of nitric oxide (NO) and reduction of carbon dioxide (CO₂). The formation of the heterojunction enhanced the transfer and separation efficiency of photogenerated carriers. Furthermore, the surface OVs sufficiently exposed catalytically active sites, and enabled capture of photoexcited electrons at the surface of the catalyst. Internal recombination of photogenerated charges was also limited, which contributed to generation of more active oxygen for NO oxidation. Heterojunction and OVs worked together to form a spatial conductive network framework, which achieved 63 % NO removal, 96 % selectivity for carbonaceous products (that is, CO and CH₄). The stability of the catalyst was confirmed by cycling experiments and X-ray diffraction and transmission electron microscopy after NO removal.     

g-C3N4光催化材料的第一性原理研究

能源短缺和环境恶化是人类社会快速发展面临的重大难题。太阳能作为一种清洁无污染的理想新型能源,具有取之不尽、用之不竭的特点,是实现可持续发展的最佳能源选择。半导体光催化可以直接利用太阳光进行催化反应,得到了广泛关注。作为一种低成本无金属光催化剂,g-C₃N₄具有独特的电子能带结构、优良的化学稳定性和热力学稳定性,在光催化领域如分解水制氢制氧、降解有机污染物、CO₂还原、抗菌和有机官能团选择性转换等方面表现出巨大的应用前景。目前g-C₃N₄光催化剂存在着如比表面积小、可见光利用率低、量子产率低和光生载流子易复合等问题,制约了其在光催化领域的应用。因此,提升g-C₃N₄光催化性能是光催化研究领域的重要课题。第一性原理具有半经验方法不可比拟的优势,已成为光催化研究领域计算和模拟的重要基础。基于密度泛函理论的第一性原理在光催化领域的广泛应用,为有效迅速地探求能够改善g-C₃N₄光催化性能的方法提供了明确的研究手段。本文从理论计算的角度综述了近年来在g-C₃N₄改性方面所取得的一些重要研究进展,主要包括元素掺杂、复合和形貌调控等改性手段。本文以g-C₃N₄改性光催化剂为研究对象,从电子性质、能带结构、光学性质和缺陷形成能的角度阐述了各种改性手段提高光催化活性的微观机理。最后,在总结前文所述各类改性研究的基础上,对g-C₃N₄改性光催化剂未来的发展趋势作出了展望。