Effect of Functional Group Modifications on the Photocatalytic Performance of g-C3N4

In recent years, photocatalysis has received increasing attention in alleviating energy scarcity and environmental treatment, and graphite carbon nitride (g-C₃N₄) is used as an ideal photocatalyst. However, it still remains numerous challenges to obtain the desirable photocatalytic performance of intrinsic g-C₃N₄. Functional group functionalization, formed by introducing functional groups into the bulk structure, is one of the common modification techniques to modulate the carrier dynamics and increases the number of active sites, offering new opportunities to break the limits for structure-to-performance relationship of g-C₃N₄. Nevertheless, the general overview of the advance of functional group modification of g-C₃N₄ is less reported yet. In order to better understand the structure-to-performance relationship at the molecular level, a review of the latest development of functional group modification is urgently needed. In this review, the functional group modification of g-C₃N₄ in terms of structures, properties, and photocatalytic activity is mainly focused, as well as their mechanism of reaction from the molecular level insights is explained. Second, the recent progress of the application of introducing functional groups in g-C₃N₄ is introduced and examples are given. Finally, the difficulties and challenges are presented, and based on this, an outlook on the future research development direction is shown.     

凹凸棒石/g-C3N4复合材料的制备及其电催化析氧性能研究

以凹凸棒石(ATP)为载体, 通过原位沉积, 结合冷冻干燥、程序焙烧工艺在其表面负载不同质量分数的类石墨相氮化碳(g-C₃N₄)薄层材料, 制备系列ATP/g-C₃N₄复合材料用于电催化析氧反应, 产物标识为ATP/g-C₃N₄-w (质量分数w = mATP: (mATP + mg-C₃N₄)=0.33、0.40、0.50、0.67), 并研究在0.1 mol/L KOH的电解液中的电催化析氧性能。结果表明: g-C₃N₄薄层通过Si-O-C键牢固负载于凹凸棒石表面, 从而有效调变g-C₃N₄表面的电子层结构, 提供更多的催化活性位点。电催化析氧测试的结果表明: ATP/g-C₃N₄-0.50具有最优的析氧催化性能, 在10 mA/cm ²电流密度下其析氧过电位为410 mV, 塔菲尔斜率为118 mV/dec, 并表现出优异的析氧稳定性。     

不同N源无定形TiO2/g-C3N4光催化还原Re(VII)性能

为探究不同N源对无定形TiO₂/g-C₃N₄(TCN)复合材料光催化还原Re(VII)的影响, 通过热分解不同前驱体(尿素Urea、硫脲Thiourea和三聚氰胺Melamine)制备g-C₃N₄, 再分别与无定形TiO₂复合, 制备了三种TCN复合光催化剂。通过不同分析手段对材料进行表征, 并比较了不同TCN复合材料光催化还原去除Re(VII)的活性差异。结果表明, U-TCN(尿素为N源)具有更均匀的表观形貌, 最大的比表面积(474 m²/g), 最优异的光吸收性能, 对Re(VII)的光催化还原效率(90%)明显高于T-TCN(20%)和M-TCN(15%)。通过复合材料的瞬态光电流和电化学阻抗(EIS)分析光催化机理, 证明U-TCN光生电子空穴分离效率最高; 电子顺磁共振波谱(EPR)分析表明U-TCN产生的羟基自由基(?OH)更多, 因此与甲酸反应产生的强还原性?CO₂^-自由基更多, 从而更有利于Re(VII)的还原; 利用同步辐射X射线吸收光谱分析Ti元素价态及配位环境, 表明U-TCN还具有优异的光化学稳定性。本研究揭示了不同N源对所制备TCN复合材料光催化性能的影响, 并发现了一种可用于实际废水中光催化还原去除Tc(VII)的优选材料。     

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。     

g-C_3N_4/TiO_2对亚甲基蓝光催化性能研究

采用偏钛酸为钛前驱体,三聚氰胺为氮源,制备g-C3N4/TiO2复合纳米光催化材料,研究不同原料配比、焙烧温度及不同焙烧时间制备的g-C3N4/TiO2光催化材料对亚甲基蓝以可见光激发降解亚甲基蓝溶液,考察其光催化活性,采用紫外-可见吸收(UV-Vis)光谱、三维荧光(FS)光谱进行机理研究。     

PANI载的孔状g-C3N4的界面聚合法制备与光催化性能研究

在孔状石墨型氮化碳(g-C₃N₄)存在下, 通过苯胺单体的界面聚合成功制备了孔状g-C₃N₄/聚苯胺(PANI)复合催化剂。采用XRD、FTIR、SEM、TGA、UV-Vis和电化学阻抗谱等对样品的结构、形貌、性能以及可见光催化降解亚甲基蓝的催化活性进行表征。结果表明: PANI组装在孔状g-C₃N₄片上, 此种复合结构不仅利于孔状g-C₃N₄对PANI链段运动的限制, 提高孔状g-C₃N₄/PANI复合催化剂的稳定性; 而且增强材料的可见光利用率、氧化能力和电子输运性能, 利于可见光催化性能的改善。     

硅藻土/g-C3N4复合材料的制备及其可见光增强活性

采用浸渍-焙烧法制备了具有可见光响应活性的硅藻土/g-C₃N₄复合光催化材料。利用TG、XRD、FE-SEM、HR-TEM、FT-IR、XPS、UV-Vis-DRS 和 PL谱等手段对其物相组成、形貌和光吸收特性进行表征。以RhB的光催化降解为探针反应评价催化剂的活性。光催化结果表明, 2.32wt%硅藻土/g-C₃N₄复合材料对RhB有较高的催化活性, 光催化降解的速率常数是纯g-C₃N₄的1.9倍。自由基捕获实验表明, ·O₂^-是RhB在硅藻土/g-C₃N₄复合材料上光催化降解的主要活性物种。光催化活性提高的主要原因在于硅藻土和g-C₃N₄之间静电作用有利于光生电子-空穴在g-C₃N₄表面的迁移, 进而提高g-C₃N₄的光催化活性。     

基于g–C3N4光催化型抗菌包装纸的制备及其抗菌性研究

目的 解决g–C3N4存在的比表面积小,电子–空穴复合速率快从而导致光催化性能不佳等问题。方法 以尿素和硫脲为前驱体材料,通过热解聚辅助水蒸气活化合成S掺杂石墨相氮化碳(g–C3N4),并用界面聚合制备出光催化型抗菌包装纸。利用扫描电镜(SEM)、红外光谱(FTIR)、水接触角(WCA)、热重分析(TGA)、光催化抗菌实验等对抗菌包装纸的形态结构、表面官能团、纸张性质、光催化抗菌性进行详细研究。结果 致密的g–C3N4层有效提高了抗菌包装纸的疏水性和热稳定性。可见光照射下,光催化型抗菌包装纸对大肠杆菌和金黄色葡萄球菌的杀灭率达100%。未经可见光照射的原纸比光催化型包装纸的抗菌性差。结论 g–C3N4光催化型抗菌包装纸具有良好的广谱抗菌性,为绿色抗菌包装材料的制备提供了新思路。     

Z型BiVO4/GO/g-C3N4复合材料的制备及其可见光下催化性能

Z-型光催化剂可以有效增强电荷分离, 从而改善光催化剂的活性。采用浸渍-煅烧和水热法两步制备Z型BiVO₄/GO/g-C₃N₄光催化剂, 并用不同手段对其进行表征。在BiVO₄/GO/g-C₃N₄的光催化过程中, GO纳米片作为BiVO₄和g-C₃N₄之间的快速传输通道, 可以抑制电子-空穴复合, 显著促进电荷分离, 提高三元异质结的氧化还原能力。与单组分或二元复合物相比, 该催化剂具有良好的光降解罗丹明B(RhB)的能力。在可见光照射下, 它能够在120 min内降解85% RhB, 空穴(h⁺)在反应中起主要作用。该工作为三元光催化剂体系提供了简单的制备方法, 其中g-C₃N₄通过GO与BiVO₄偶联, 光催化活性显著提高。     

MOFs自牺牲模板法制备CoNx/g-C3N4纳米材料用作高效光催化还原U(VI)

近年来, 利用石墨氮化碳(g-C₃N₄)光催化法将易溶的U(VI)还原为难溶的U(IV)来清除铀, 已逐渐成为放射性核素研究的热点。本研究将一种含金属钴的金属有机框架材料(MOFs)作为自牺牲模板, 利用简单热共聚法成功合成了含有Co-N_x构型的CoN_x/g-C₃N₄催化剂。在固液比为1.0 g/L、pH 5.0、可见光照射45 min下, 制备的催化剂(w(Co-MOFs) : w(g-C₃N₄)=1 : 1)对50 mg/L的U(VI)标准溶液还原率达到100%。从形貌, 微观结构和光学性能等方面对催化剂进行了表征,结果显示, 引入Co有效拓宽了g-C₃N₄对可见光的吸收范围, 抑制了光生电子与空穴的复合, 从而促进了U(VI)的还原反应。此外, 基于捕获实验深入探究了U(VI)在CoN_x/g-C₃N₄材料表面催化可能的反应机理。研究表明, CoN_x/g-C₃N₄复合光催化剂光学性能优异, 制备方法简单且绿色环保, 对放射性废水中的U(VI)的光催化还原去除效果较好。本工作对后续石墨氮化碳类新型材料的设计、合成与实际应用具有一定的参考作用。     

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。     

CTAB作用下TiO2/g-C3N4的制备及光催化降解偏二甲肼废水

在十六烷基三甲基溴化铵(CTAB)作用下,采用水热合成法制备TiO 2/g-C 3N 4复合材料,研究CTAB对复合材料结构及光谱性质的影响。采用XRD、TEM、N 2吸附-脱附、FT-IR、UV-Vis DRS、PL等测试手段对材料进行表征,并在可见光下进行光催化降解偏二甲肼(UDMH)废水实验。结果表明:在CTAB作用下合成的TiO 2/g-C 3N 4复合材料晶型结构完整,TiO 2粒径更小并且在g-C 3N 4片层上均匀分布,具有较大的比表面积和丰富的介孔结构,复合材料的光吸收带边拓展至450nm,光生空穴-电子复合率明显降低。光催化实验表明,可见光条件下反应120min,UDMH的去除率达到了83.2%,相比未添加CTAB制备的TiO 2/g-C 3N 4提升了13.7%。     

Template-free preparation of non-metal (B,P,S) doped g-C3N4 tubes with enhanced photocatalytic H2O2 generation

Developing environmentally friendly methods to produce hydrogen peroxide (H2O2) has received increas-ing attention.Photocatalysis has been proved to be a sustainable technology for H2O2 production.Herein,the novel non-metal elements (B,P,and S) doped g-C3N4 tubes (B-CNT,P-CNT,and S-CNT) photocata-lysts were obtained via a hydrothermal synthesis followed by thermal polymerization.By adjusting the precursor,the yield of g-C3N4 tubes (CNT) materials has been greatly improved.The as-prepared B-CNT,P-CNT,and S-CNT photocatalysts show an enhanced photocatalytic H2O2 production with the formation rate constants values of 42.31 μM min-1,24.95μM min-1,and 24.22μM min-1,respectively,which is higher than that of bulk CN (16.40 μM min-1).The doped B,P,S elements significantly enhanced the photocatalytic activity by adjusting their electronic structures and promoting the separation of electron-hole carriers.The results have shown great potential for the practical application of CNT photocatalysts.     

Confined reaction inside nanotubes: New approach to mesoporous g-C3N4 photocatalysts

Mesoporous g-C3N4 nanorods (NRs) are synthesized through the nano-confined thermal condensation of cyanamide in silica nanotubes (NTs) with porous shells.The gas bubbles retained during condensation and the limited cyanamide precursor inside the silica NTs lead to the formation of mesoporous g-C3N4.This nano-confined reaction is an alternative method to the traditional templating process for the synthesis of mesoporous materials.The as-prepared mesoporous g-C3N4 NRs exhibit remarkably improved photocatalytic activity and high stability in water splitting and degradation of Rhodamine B compared with bulk g-C3N4.     

一步法合成磷掺杂石墨相氮化碳及其光催化性能

以尿素(CO(NH₂)₂)和磷酸氢二铵((NH₄)₂HPO₄)作为原料, 通过热聚合法制备了磷(P)掺杂石墨相氮化碳(g-C₃N₄)材料(P-CN)。通过X射线衍射、红外光谱、X射线光电子谱、扫描电子显微镜、透射电子显微镜、紫外可见漫反射光谱和N₂吸附-脱附对样品进行了表面形貌及结构表征, 通过对罗丹明B(RhB)的降解实验, 研究了样品的可见光催化性能, 对其催化机理进行了分析。结果表明, 合成过程中磷原子的掺杂会取代g-C₃N₄中的C原子, 从而改变g-C₃N₄的表面形貌和电子结构。在可见光条件下, P-CN材料表现出优异的光催化性能, 其对RhB的降解速率明显优于纯氮化碳。其中3%P-CN样品催化活性最高, 反应30 min时, RhB降解率达到96.8%。分析认为, P原子对g-C₃N₄中的C原子的取代使P-CN样品表面处于富电子状态, 并导致P-CN样品导带位置升高, 光电子还原性增强。这些电子与水中的溶解氧形成超氧自由基(·O₂^-), 从而使得光催化性能显著提高。     

可见光驱动RGO/g-C3N4活化过硫酸盐降解水中双酚A

光催化氧化法能够高效去除水体中的持久性有机污染物, 在污水净化领域展现出广阔的应用前景。本研究分别以尿素和双氰胺为原料, 采用冷干辅助热聚合法制备了还原性氧化物石墨烯/氮化碳(RGO/g-C₃N₄)二元可见光催化剂, 并对样品的形貌结构和光学性能进行了分析表征。结果表明, 二维层状g-C₃N₄与RGO在异质结界面上紧密的结合在一起。同时以内分泌干扰物双酚A (BPA)为降解污染物, 研究了不同催化剂在可见光下活化过硫酸盐去除BPA的活性。光催化实验结果显示, 在可见光(λ>420 nm)照射下, 加入氧化剂过硫酸盐(PS)作为电子受体, 有效地增强了光催化剂可见光降解BPA的活性。以尿素为原料制备的RGO/g-C₃N₄催化剂在40 min内几乎完全去除溶液中的BPA。经过5次循环反应后, 可见光照射40 min, 该催化剂对BPA的去除率仍能达到80%以上, 表现出良好的稳定性。     

Constructing CdSe QDs modified porous g-C3N4 heterostructures for visible light photocatalytic hydrogen production

Constructing heterostructures with narrow-band-gap semiconductors is a promising strategy to extend light absorption range of graphitic carbon nitride (g-C3N4) and simultaneously promote charge separa-tion for its photocatalytic activity improvement.However,its highly localized electronic states of g-C3N4 hinder photo-carrier migration through bulk towards heterostructure interfaces,resulting in low charge carrier separation effidency of solid bulk g-C3N4-based heterostructures.Herein,porous g-C3N4 (PCN)material with greatly shortened migration distance of photo-carriers from bulk to surface was used as an effective substrate to host CdSe quantum dots to construct type Ⅱ heterostructure of CdSe/PCN for pho-tocatalytic hydrogen production.The homogeneous modification of the CdSe quantum dots throughout the whole bulk of PCN together with proper band alignments between CdSe and PCN enables the ef-fective separation of photo-generated charge carriers in the heterostructure.Consequently,the CdSe/PCN heterostructure photocatalyst gives the greatly enhanced photocatalytic hydrogen production activity of 192.3 μmol h-1,which is 4.4 and 8.1 times that of CdSe andPCN,respectively.This work provides a fea-sible strategy to construct carbon nitride-based heterostructure photocatalysts for boosting visible light driven water splitting performance.     

Reversible Stacking of 2D ZnIn2S4 Atomic Layers for Enhanced Photocatalytic Hydrogen Evolution

It is technically challenging to reversibly tune the layer number of 2D materials in the solution. Herein, a facile concentration modulation strategy is demonstrated to reversibly tailor the aggregation state of 2D ZnIn₂S₄ (ZIS) atomic layers, and they are implemented for effective photocatalytic hydrogen (H₂) evolution. By adjusting the colloidal concentration of ZIS (ZIS-X, X = 0.09, 0.25, or 3.0 mg mL⁻¹), ZIS atomic layers exhibit the significant aggregation of (006) facet stacking in the solution, leading to the bandgap shift from 3.21 to 2.66 eV. The colloidal stacked layers are further assembled into hollow microsphere after freeze-drying the solution into solid powders, which can be redispersed into colloidal solution with reversibility. The photocatalytic hydrogen evolution of ZIS-X colloids is evaluated, and the slightly aggregated ZIS-0.25 displays the enhanced photocatalytic H₂ evolution rates (1.11 µmol m⁻² h⁻¹). The charge-transfer/recombination dynamics are characterized by time-resolved photoluminescence (TRPL) spectroscopy, and ZIS-0.25 displays the longest lifetime (5.55 µs), consistent with the best photocatalytic performance. This work provides a facile, consecutive, and reversible strategy for regulating the photo-electrochemical properties of 2D ZIS, which is beneficial for efficient solar energy conversion.     

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。     

Porous g-C3N4-encapsulated TiO2 hollow sphere as a high-performance Z-scheme hybrid for solar-induced photocatalytic abatement of environmentally toxic pharmaceuticals

Herein,we rationally constructed a hybrid heterostructure comprising porous g-C3N4(CN)-encapsulated anatase TiO2 hollow spheres(TOHS)via a synthesis method that involves hydrothermal and calcination treatments.The fabricated hybrid,termed CN/TOHS,demonstrated extraordinary activity toward the degradation of environmentally toxic pharmaceutical substances(acetaminophen and ciprofloxacin)in aqueous solutions under simulated sunlight irradiation;the activity of CN/TOHS was superior to that attained for individual TOHS and CN counterparts.In particular,the CN/TOHS hybrid containing 13.3 wt.％of CN on TOHS displayed the optimum degradation activity among the tested catalysts used in this study,and it also possessed exceptional recyclability and stability during consecutive degradation tests.The remarkable photocatalytic activity and stability of the hybrid were predominantly ascribed to the large solid interfacial contact between constituents,TOHS and CN,induced by effective hybrid structure,which boosted the interfacial charge transfer and impeded with the direct recombination of photo-induced charges.Notably,the results of the liquid chromatography-mass spectrometry analysis corroborated the effective mineralization of model pharmaceutical pollutants in the presence of the CN/TOHS hybrid.The simple interfacial engineering strategy presented in this study offers a potential route for the rational design of novel catalysts for application in environmental remediation and solar energy conversion.