In Situ Synthesis of Cu3P/P-Doped g-C3N4 Tight 2D/2D Heterojunction Boosting Photocatalytic H2 Evolution†

Heterojunction design in a two-dimensional (2D) fashion has been deemed beneficial for improving the photocatalytic activity of g-C₃N₄ because of the promoted interfacial charge transfer, yet still facing challenges. Herein, we construct a novel 2D/2D Cu₃P nanosheet/P-doped g-C₃N₄ (PCN) nanosheet heterojunction photocatalyst (PCN/Cu₃P) through a simple in-situ phosphorization treatment of 2D/2D CuS/g-C₃N₄ composite for photocatalytic H₂ evolution. We demonstrate that the 2D lamellar structure of both CuS and g-C₃N₄ could be well reserved in the phosphorization process, while CuS and g-C₃N₄ in-situ transformed into Cu₃P and PCN, respectively, leading to the formation of PCN/Cu₃P tight 2D/2D heterojunction. Owing to the large contact area provided by intimate face-to-face 2D/2D structure, the PCN/Cu₃P photocatalyst exhibits significantly enhanced charge separation efficiency, thus achieving a boosted visible-light-driven photocatalytic behavior. The highest rate for H₂ evolution reaches 5.12 μmol·h^–1, nearly 24 times and 368 times higher than that of pristine PCN and g-C₃N₄, respectively. This work represents an excellent example in elaborately constructing g-C₃N₄-based 2D/2D heterostructure and could be extended to other photocatalyst/co-catalyst system.      

Interfacial engineering of graphitic carbon nitride (g-C3N4)-based metal sulfide heterojunction photocatalysts for energy conversion: A review

As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemical, graphitic carbon nitride (g-C₃N₄) has become research hotspots in the community. However, g-C₃N₄ photocatalyst still suffers from many problems, resulting in unsatisfactory photocatalytic activity such as low specific surface area, high charge recombination and insufficient visible light utilization. Since 2009, g-C₃N₄-based heterostructures have attracted the attention of scientists worldwide for their greatly enhanced photocatalytic performance. Overall, this review summarizes the recent advances of g-C₃N₄-based nanocomposites modified with transition metal sulfide (TMS), including (1) preparation of pristine g-C₃N₄, (2) modification strategies of g-C₃N₄, (3) design principles of TMS-modified g-C₃N₄ heterostructured photocatalysts, and (4) applications in energy conversion. What is more, the characteristics and transfer mechanisms of each classification of the metal sulfide heterojunction system will be critically reviewed, spanning from the following categories: (1) Type I heterojunction, (2) Type II heterojunction, (3) p-n heterojunction, (4) Schottky junction and (5) Z-scheme heterojunction. Apart from that, the application of g-C₃N₄-based heterostructured photocatalysts in H₂ evolution, CO₂ reduction, N₂ fixation and pollutant degradation will also be systematically presented. Last but not least, this review will conclude with invigorating perspectives, limitations and prospects for further advancing g-C₃N₄-based heterostructured photocatalysts toward practical benefits for a sustainable future.     

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.     

Water Transport with Ultralow Friction through Partially Exfoliated g-C3N4 Nanosheet Membranes with Self-Supporting Spacers

Two-dimensional (2D) graphitic carbon nitride (g-C₃N₄) nanosheets show brilliant application potential in numerous fields. Herein, a membrane with artificial nanopores and self-supporting spacers was fabricated by assembly of 2D g-C₃N₄ nanosheets in a stack with elaborate structures. In water purification the g-C₃N₄ membrane shows a better separation performance than commercial membranes. The g-C₃N₄ membrane has a water permeance of 29 L m⁻² h⁻¹ bar⁻¹ and a rejection rate of 87 % for 3 nm molecules with a membrane thickness of 160 nm. The artificial nanopores in the g-C₃N₄ nanosheets and the spacers between the partially exfoliated g-C₃N₄ nanosheets provide nanochannels for water transport while bigger molecules are retained. The self-supported nanochannels in the g-C₃N₄ membrane are very stable and rigid enough to resist environmental challenges, such as changes to pH and pressure conditions. Permeation experiments and molecular dynamics simulations indicate that a novel nanofluidics phenomenon takes place, whereby water transport through the g-C₃N₄ nanosheet membrane occurs with ultralow friction. The findings provide new understanding of fluidics in nanochannels and illuminate a fabrication method by which rigid nanochannels may be obtained for applications in complex or harsh environments.     

Facile synthesis of GO as middle carrier modified flower-like BiOBr and C3N4 nanosheets for simultaneous treatment of chromium(VI) and tetracycline

A novel GO modified g-C₃N₄ nanosheets/flower-like BiOBr hybrid photocatalyst is fabricated by a facile method. The characterization results reveal that wrinkled GO is deposited between g-C₃N₄ nanosheets and flower-like BiOBr forming a Z-scheme heterojunction. As a mediator, plicate GO plays a positive role in prompting photogenerated electrons transferring through its sizeable 2D/2D contact surface area. The g-C₃N₄/GO/BiOBr hybrid displays a superior photocatalytic ability to g-C₃N₄ and BiOBr in photodegrading tetracycline (TC), whose removal efficiency could reach 96% within 2 h. Besides, g-C₃N₄/GO/BiOBr composite can reduce Cr(VI), and simultaneously treat TC and Cr(VI) combination contaminant under the visible light. The g-C₃N₄/GO/BiOBr ternary composite also exhibits satisfactory stability and reusability after four cycling experiments. Further, a feasible mechanism related to the photocatalytic process of g-C₃N₄/GO/BiOBr is put forward. This study offers a ternary hybrid photocatalyst with eco-friendliness and hopeful application in water pollution.     

A simple and rapid route for synthesizing the nanosized g-C3N4 materials with narrow bandgap and their photocatalytic activity

The graphitic carbon nitride (g-C₃N₄) materials with many intriguing properties have attracted much attention in photocatalysis. The photocatalytic activity of g-C₃N₄ is hindered by serious aggregation and limited exposed active sites. Herein is shown that nanosized g-C₃N₄ can be simply obtained by a superfast high-pressure homogenization approach. The high-pressure homogenization treatment can provide strong force to cut and/or to exfoliate the bulk g-C₃N₄ into nanosized g-C₃N₄ with good dispersion. Moreover, choosing different solvents during treatment can cause a different surface structure of as-prepared nanosized g-C₃N₄. In addition, the narrow bandgap properties, the high photogenerated charge carrier separation, and the transport abilities are achieved in as-prepared nanosized g-C₃N₄ because of the retaining conjugated C₃N₄ system. Specifically, the photocatalytic activities of as-prepared nanosized g-C₃N₄ have been significantly enhanced in terms of degradation of organic dye Rhodamine B (RhB) under visible light irradiation (10 times higher than that of bulk g-C₃N₄). These findings can provide a promising and simple approach to the exfoliation, nanonization, and surface functionalization of 2D layered materials.     

Exploring recent advances in silver halides and graphitic carbon nitride-based photocatalyst for energy and environmental applications

Engineering visible light active photocatalytic systems for renewable energy production and environmental remediation has always been a promising technology to counter overall energy demands and pollution challenges. As a fascinating conjugated polymer graphitic carbon nitride (g-C₃N₄) has been developed as a hotspot in the research field as a metal-free semiconducting material with the appealing band gap of 2.7 eV. Recently, g-C₃N₄ has gained tremendous interest in photocatalytic wastewater abatement as well as for hydrogen (H₂) generation, carbon dioxide (CO₂) reduction, and pollutant degradation, under exposure to visible light. Plasmonic silver halides (AgX) such as AgCl, AgBr, and AgI as plasmonic photocatalyst have received immense research interest owing to their escalating photocatalytic efficacy and strong surface plasmon resonance effect (SPR). AgX is the photosensitive, broad bandgap semiconducting materials with effectual antimicrobial properties. This review summarizes the heterostructure of carbonaceous g-C₃N₄ with plasmonic AgX, to reduce the recombination of photo-generated charge carriers, thus enhancing the natural light absorption. g-C₃N₄ grafted AgX nanoarchitectures can be utilized for several potential applications, for instance, overall water splitting (OWS), CO₂ conversion to hydrocarbon fuels, pollutant exclusion, and antibacterial disinfection. This review focuses on the evolution of g-C₃N₄ as well as AgX, facile, and synthetic routes for fabrication of g-C₃N₄ tailored AgX, construction of nano-junctions (AgX/g-C₃N₄) with various photocatalytic applications. Finally, we provided a viewpoint of current hassles and some perceptions of novel trends in this exciting as well as developing research arena.     

The preparation,and applications of g-C<Subscript>3</Subscript>N<Subscript>4</Subscript>/TiO<Subscript>2</Subscript> heterojunction catalysts—a review

In recent years, more and more attention has been paid in the research of heterojunction catalysts, due to their better catalytic ability than that of single component catalysts. Up to now, many kinds of heterojunction catalysts have been reported, such as Bi₂O₃/Bi₂WO₆, WO₃/BiVO₄, SnO₂/TiO₂, CdS/TiO₂, Ta₃N₅/Pt/IrO₂ and so on, among which the heterojunction catalyst composed of g-C₃N₄ and TiO₂ has been studied tremendously recently, due to the high activity, high thermal and chemical stability, and well matched energy structure of them. Up to now, many methods have been explored for the synthesis of g-C₃N₄/TiO₂ heterojunction catalysts, such as ball milling of g-C₃N₄ and TiO₂, hydrothermal growth of TiO₂ on g-C₃N₄ and so on. In this review, the recent researches on the synthesis of g-C₃N₄/TiO₂ catalysts were summarized. Moreover, the applications of g-C₃N₄/TiO₂ catalysts in the field of photocatalysis were detailedly introduced.     

A Targeted Review of Current Progress,Challenges and Future Perspective of g-C3N4 based Hybrid Photocatalyst Toward Multidimensional Applications

The increasing demand for searching highly efficient and robust technologies in the context of sustainable energy production totally rely onto the cost-effective energy efficient production technologies. Solar power technology in this regard will perceived to be extensively employed in a variety of ways in the future ahead, in terms of the combustion of petroleum-based pollutants, CO₂ reduction, heterogeneous photocatalysis, as well as the formation of unlimited and sustainable hydrogen gas production. Semiconductor-based photocatalysis is regarded as potentially sustainable solution in this context. g-C₃N₄ is classified as non-metallic semiconductor to overcome this energy demand and enviromental challenges, because of its superior electronic configuration, which has a median band energy of around 2.7 eV, strong photocatalytic stability, and higher light performance. The photocatalytic performance of g-C₃N₄ is perceived to be inadequate, owing to its small surface area along with high rate of charge recombination. However, various synthetic strategies were applied in order to incorporate g-C₃N₄ with different guest materials to increase photocatalytic performance. After these fabrication approaches, the photocatalytic activity was enhanced owing to generation of photoinduced electrons and holes, by improving light absorption ability, and boosting surface area, which provides more space for photocatalytic reaction. In this review, various metals, non-metals, metals oxide, sulfides, and ferrites have been integrated with g-C₃N₄ to form mono, bimetallic, heterojunction, Z-scheme, and S-scheme-based materials for boosting performance. Also, different varieties of g-C₃N₄ were utilized for different aspects of photocatalytic application i. e., water reduction, water oxidation, CO₂ reduction, and photodegradation of dye pollutants, etc. As a consequence, we have assembled a summary of the latest g-C₃N₄ based materials, their uses in solar energy adaption, and proper management of the environment. This research will further well explain the detail of the mechanism of all these photocatalytic processes for the next steps, as well as the age number of new insights in order to overcome the current challenges.     

Ag nanoparticles loaded on porous graphitic carbon nitride with enhanced photocatalytic activity for degradation of phenol

Highly efficient photocatalyst of visible-light-driven Ag nanoparticles loaded on porous graphitic carbon nitride (g-C₃N₄) was prepared by the reduction of Ag ions on porous g-C₃N₄. The obtained Ag/porous g-C₃N₄ composite products were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectra (DRS), thermal gravimetric analysis (TGA). The results demonstrated that a homogeneous distribution of Ag NPs of 10 nm was attached onto the surface of the porous g-C₃N₄. The prepared Ag/porous g-C₃N₄ samples were applied for catalyzing the degradation of phenol in water under visible light irradiation. Porous g-C₃N₄ demonstrated an excellent support for the formation and dispersion of small uniform Ag NPs. When the weight percentage of Ag reaches 5%, the nanohybrid exhibits superior photocatalytic activities compared to bulk g-C₃N₄, porous g-C₃N₄, and 2% Ag/porous g-C₃N₄ hybrids. The enhanced photocatalytic performance is due to the synergic effect between Ag and porous g-C₃N₄, which suppressed the recombination of photogenerated electron-hole pairs.     

Upgraded charge transport in g-C3N4 nanosheets by boron doping and their heterojunction with 3D CdIn2S4 for efficient photodegradation of azo dye

The facilitation of charge transport toward the targeted chemical reaction is a challenging task for two-dimensional (2D) nanomaterials. We demonstrate the effectiveness of two different strategies, non-metal doping and heterojunction formation, to adjust the electronic and molecular structures of g-C₃N₄ nanosheets (CN), which could widen the visible-light response and improve the photo-induced electron–hole separation. The g-C₃N₄ nanosheets containing impurity levels (boron doping (BCN)) were prepared by a high-temperature solid-state reaction. Additionally, by anchoring the 3D dichalcogenide structures (CdIn₂S₄) elicited by a wet chemical route, hybrid BCN/CdIn₂S₄ nanostructures were obtained. The resulting BCN/CdIn₂S₄ (BCN–CIS3) nanostructures exhibited an excellent degradation efficiency (95%) for methyl orange (MO) compared to pristine g-C₃N₄ nanosheets (CN) (28%) and boron-doped g-C₃N₄ (BCN) (35%). All the optimized photocatalysts were thoroughly characterized using various techniques and investigated for comparative structural, optical, morphological, and catalytic properties. Our results reveal that introducing boron atoms into the lattice of g-C₃N₄ nanosheets leads to reduction in the band-gap energy and rapid electron transfer. The formation of heterojunctions with the 3D CdIn₂S₄ further assists in improving the degradation efficiency by minimizing the undesired electron–hole recombination, as confirmed by time-resolved photoluminescence (TRPL) analysis. This work proposes feasible strategies and their synergy to develop innovative materials for sustainable energy conversion and environmental remediation applications.     

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。     

单分散g-C3N4量子点修饰一维棒状BiPO4微晶的合成及其对光催化活性增强机理

利用水热法合成了一维棒状BiPO₄微晶,在此基础上采用浸渍-被烧法进行g-C₃N₄量子点表面修饰获得新颖的g-C₃N₄/BiPO₄异质结。借助X射线衍射(XRD)、场发射扫描电镜(FE-SEM)、透射电镜(HRTEM)、能谱(EDS)、紫外-可见漫反射(UV-Vis-DRS)等测试手段对所得样品的相组成、形貌和谱学特征进行了表征。选择罗丹明B(RhB)和苯酚作为模型污染物研究了所得在可见光下的催化活性。结果表明,样品16%(w/w) g-C₃N₄/BiPO₄对RhB降解的速率常数分别是纯和的g-C₃N₄和BiPO₄的16倍和4.6倍。g-C₃N₄量子点与BiPO₄之间形成异质结,抑制了光生电子-空穴对的复合,从而提高了催化剂的活性。自由基捕获实验进一步表明,超氧负离子自由基(·O₂-)是催化降解RhB和苯酚的主要活性物种。     

Honeycomb-like g-C3N4/CeO2-x nanosheets obtained via one step hydrothermal-roasting for efficient and stable Cr(VI) photo-reduction

Graphitic carbon nitride (g-C₃N₄)-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy. In this work, we reported a facile one step in-situ hydrothermal-roasting method for preparing honeycomb-like g-C₃N₄/CeO₂ nanosheets with abundant oxygen vacancies (g-C₃N₄/CeO_2-x). The hydrothermal-roasting and incomplete-sealed state can (i) generate an in-situ reducing atmosphere (CO, N₂, NH₃) to tune the concentration of oxygen vacancies in CeO₂; (ii) beneficial to prevent continuous growth of g-C₃N₄ and results in honeycomb-like g-C₃N₄/CeO_2-x hybrid nanosheets. What is more, the g-C₃N₄/CeO_2-x photocatalyst exhibited extended photoresponse range, increased specific surface area and obviously enhanced separation efficiency of photogenerated electron-hole pairs. As a proof-of-concept application, the optimized g-C₃N₄/CeO_2-x nanosheets could achieve 98% removal efficiency for Cr(VI) under visible light irradiation (λ ≥ 420 nm) within 2.5 h, which is significantly better than those of pure g-C₃N₄ and CeO₂. This work provides a new idea for more rationally designing and constructing g-C₃N₄-based catalysts for efficient extended photochemical application.     

溶液法剥离的氮化碳在各种衬底上分散的AFM研究

石墨相氮化碳(g-C_3N_4)因为其特殊的层状结构及电子性质在催化和光催化领域里受到广泛关注和研究。本文以异丙醇及异丙醇-水混合溶液为介质对g-C_3N_4粉末进行超声液相剥离,并利用原子力显微镜详细表征了剥离后的溶液分散至云母、高定向热解石墨(HOPG)、Au(111)等不同衬底表面的结果。发现溶液经10h超声后,g-C_3N_4被剥离成尺寸约100nm左右的扁平颗粒,但无法形成完美的超薄层结构。这可能是由于经热聚合法合成的g-C_3N_4本身晶化程度较低所致。     

氮缺陷对GaN/g-C3N4异质结电子结构和光学性能影响的第一性原理研究

基于密度泛函理论下的第一性原理平面波超软赝势方法,研究了单层GaN、g-C₃N₄、GaN/g-C₃N₄异质结及3种氮缺陷GaN/g-C₃N₄-V_XN （X=1、2、3）异质结的稳定性、电子结构、功函数及光学性能。计算结果表明,GaN/g-C₃N₄异质结体系晶格失配率极低（0.8%）,属于完全共格。与单层g-C₃N₄相比,GaN/g-C₃N₄和GaN/g-C₃N₄-V_XN （X=1、2、3）异质结的导带向低能方向偏移,价带上移,从而导致带隙减小,且态密度均显示出轨道杂化现象。GaN/g-C₃N₄和GaN/g-C₃N₄-V_XN （X=1、2、3）异质结在界面处均形成了电势差,在其内部形成了从g-C₃N₄层指向GaN层的内置电场。GaN/g-C₃N₄-V_1N异质结的界面电势差值最大且红移现象最为明显,表明GaN/g-C₃N₄-V_1N异质结相较其他2个N缺陷异质结光学性能最好。氮缺陷的引入在不同程度上提高了GaN/g-C₃N₄异质结在红外光区域的光吸收能力。     

氮缺陷对GaN/g-C3N4异质结电子结构和光学性能影响的第一性原理研究

基于密度泛函理论下的第一性原理平面波超软赝势方法,研究了单层GaN、g-C₃N₄、GaN/g-C₃N₄异质结及3种氮缺陷GaN/g-C₃N₄-V_XN(X=1、2、3)异质结的稳定性、电子结构、功函数及光学性能。计算结果表明,GaN/g-C₃N₄异质结体系晶格失配率极低(0.8%),属于完全共格。与单层g-C₃N₄相比,GaN/g-C₃N₄和GaN/g-C₃N₄-V_XN(X=1、2、3)异质结的导带向低能方向偏移,价带上移,从而导致带隙减小,且态密度均显示出轨道杂化现象。GaN/g-C₃N₄和GaN/g-C₃N₄-V_XN(X=1、2、3)异质结在界面处均形成了电势差,在其内部形成了从g-C₃N₄层指向GaN层的内置电场。GaN/g-C₃N₄-V_1N异质结的界面电势差值最大且红移现象最为明显,表明GaN/g-C₃N₄-V_1N异质结相较其他2个N缺陷异质结光学性能最好。氮缺陷的引入在不同程度上提高了GaN/g-C₃N₄异质结在红外光区域的光吸收能力。     

Combination of Ag2CrO4 and AgI semiconductors with g-C3N4: Novel nanocomposites with substantially improved photocatalytic performance under visible light

Novel g-C₃N₄/Ag₂CrO₄/AgI nanocomposites with improved photocatalytic performance under visible light were synthesized by consecutive deposition of Ag₂CrO₄ and AgI semiconductors over g-C₃N₄ sheets by refluxing method. The synthesized g-C₃N₄/Ag₂CrO₄/AgI photocatalysts were fully characterized by XRD, EDX, SEM, TEM, UV–vis DRS, TGA, FT-IR, and PL instruments. Photocatalytic performance of g-C₃N₄/Ag₂CrO₄/AgI (30%) nanocomposite for degradation of RhB was 27.9, 4.0, and 3.1 folds greater than those of the g-C₃N₄, g-C₃N₄/Ag₂CrO₄ (20%), and g-C₃N₄/AgI (30%) photocatalysts, respectively. The substantially increased photocatalytic performance was related to efficient retardation of the charge carriers from recombination and more absorbing of visible light, due to the synergistic effects of Ag₂CrO₄ and AgI on g-C₃N₄. The photocatalytic performance of the ternary nanocomposite did not considerably change after several cycles, indicating that the ternary nanocomposite is stable and it could be reused in successive runs.     

Density functional theory study on sensing properties of g-C3N4 sheet to atmospheric gasses: Role of zigzag and armchair edges

The ability of the polymer-based graphitic carbon nitride (g-C₃N₄) as a gas sensor toward NO, NO₂, CO, CO₂, SO₂, SO₃, and O₂ gasses is assessed using density functional theory (DFT) calculations in terms of energetic and electronic transport characteristics. In particular, this study is aimed to explore the role of zigzag and armchair edges of the g-C₃N₄ sheet on sensing performances. The electronic properties of adsorption systems, such as Bader charge analysis, band gaps, work function, and density of states (DOS), are used to understand the interaction between the adsorbed gas molecules and the g-C₃N₄ sheet. Our calculated results indicate that SOx (SO₃ and SO₂) gasses have higher adsorption energies on the g-C₃N₄ sheet than other gasses. Furthermore, the transport properties, such as current–voltage (I-V) and resistance-voltage (R-V) curves along the zigzag and armchair directions are calculated using the non-equilibrium Green's function (NEGF) method to understand the performance of the g-C₃N₄ sheet as a prominent conductive/resistive sensor. The I-V/R-V results indicate that the zigzag g-C₃N₄ sheet has excellent sensing ability toward SOx gasses at low applied voltages. However, the presence of H₂O degrades the sensing performance of the armchair g-C₃N₄ sheet. Theoretical recovery time has also been calculated to evaluate the reusability of g-C₃N₄ sheet-based gas sensors. Our results reveal that the zigzag g-C₃N₄ sheet-based sensing device has a remarkably high sensitivity (>300%) and selectivity toward SOx gasses and has the potential to work in a complex environment.     

凹凸棒石/g-C3N4-AgFeO2复合材料制备及其光催化性能

以凹凸棒石(简称凹土,ATP)为基体,通过原位化学法一步直接合成g-C_3N_4薄层材料,并将其有效固载于凹土表面(ATP/gC_3N_4),再通过原位沉淀法引入不同比例AgFeO_2纳米颗粒,构筑系列兼具磁分离特性和高效光催化活性的ATP/g-C_3N_4-AgFeO_2-Y复合光催化剂(Y=wATP/g-C_3N_4/(wATP/g-C_3N_4+wAg FeO_2)×100%,表示ATP/g-C_3N_4在ATP/g-C_3N_4-AgFeO_2复合材料中所占的质量百分数)。采用XRD、SEM、BET、UV-Vis、PL和ICP表征其结构和物化性能,以酸性红G(ARG)为目标降解物,研究其光催化性能。研究发现:通过形成Si-O-C键,g-C_3N_4薄层被均匀固定在凹土表面;AgFeO_2纳米颗粒均匀沉积于ATP/g-C_3N_4表面并形成Z型异质结,ATP/gC_3N_4-AgFeO_2-Y具有比ATP/g-C_3N_4和AgFeO_2更优异的可见光光催化性能,且随着ATP/g-C_3N_4含量的增大呈先升高而后下降的趋势;当Y=57%时复合材料的性能最佳,ATP/g-C_3N_4-AgFeO_2-57%对20 mg·L-1酸性红G的降解率可达97.4%,循环4次使用后,降解率仍保持94.2%。通过自由基捕获实验研究了光催化反应机理,发现·O2-是光催化过程的主要活性物种。