石墨相氮化碳负载磷钨酸杂化材料的制备及其氧化脱硫催化性能

以1-丁基-3-甲基咪唑溴离子液体([Bmim]Br)、磷钨酸(H_3PW_(12)O_(40))和g-C_3N_4为原料,采用原位沉淀法合成了负载型[Bmim]_3PW_(12)O_(40)/g-C_3N_4催化剂(BPWO/g-C_3N_4)。通过XRD、FT-IR、UV-vis、氮气吸附、TEM和XPS等手段对催化剂的形貌和结构进行了表征,并以二苯并噻吩(DBT)的正庚烷溶液为模拟油、过氧化氢为氧化剂,考察了各组分负载量、催化剂用量、氧/硫物质的量比(O/S)和反应温度变量等对其氧化脱硫效果的影响。结果表明,BPWO/g-C_3N_4具有Keggin型杂多阴离子结构特征,BPWO (20%)/g-C_3N_4催化剂具有最优的对DBT的氧化脱硫性能,在50℃、O/S物质的量比为6.0的条件下反应180 min,可以完全氧化浓度为800μg/g的含DBT模拟油。同时,该BPWO/g-C_3N_4催化剂具有良好的重复使用性能,循环使用八次后其对DBT的氧化活性没有明显降低。     

质子化g-C3N4/β-SiC复合材料的制备及光催化降解茜素红性能

分别采用热解法和溶胶-凝胶-碳热还原法合成了石墨相氮化碳(g-C₃N₄)和纳米级碳化硅(β-SiC), 通过浸渍-热处理法将两者复合并通过浓盐酸质子化, 分别制备了g-C₃N₄/β-SiC和质子化g-C₃N₄/β-SiC(P-g-C₃N₄/β-SiC)复合光催化剂. 利用X射线衍射(XRD)、 扫描电子显微镜(SEM)、 高分辨透射电子显微镜(HRTEM)、 傅里叶变换红外光谱(FTIR)、 X射线光电子能谱(XPS)、 紫外-可见漫反射光谱(UV-Vis-DRS)和光致发光光谱(PL)等对样品进行了表征. 结果表明, P-g-C₃N₄/β-SiC复合材料的比表面积增大, 光生电子-空穴对的复合几率降低, 光催化性能明显提高. 在光催化降解染料茜素红(ARS)研究中, 样品的可见光催化活性顺序为P-g-C₃N₄/β-SiC>g-C₃N₄/β-SiC>P-g-C₃N₄>g-C₃N₄>β-SiC. 其中P-g-C₃N₄/β-SiC在60 min内对ARS的降解效率高达99.9%, 符合准一阶动力学模型, 速率常数为0.0967 min ^-1, 且循环使用9次后, 光催化降解效率仍保持97.5%以上.     

聚咪唑/氮化碳新型纳米复合材料修饰电极对尿酸、黄嘌呤和次黄嘌呤的同时检测

以三聚氰胺为原料, 采用热聚合法合成了类石墨烯状二维片状氮化碳(g-C₃N₄)纳米材料; 通过电沉积和高电位氧化的方法制得氧化聚咪唑(PImox)/g-C₃N₄修饰电极(PImox/g-C₃N₄/GCE). 采用扫描电子显微镜(SEM)和X射线粉末衍射仪(XRD)对g-C₃N₄纳米材料进行了表征; 通过循环伏安法(CV)和差分脉冲伏安法(DPV)考察了尿酸(UA)、 黄嘌呤(XA)和次黄嘌呤(HX)在该电极上的电化学行为. 结果表明, UA, XA和HX的检测线性范围分别为2.0~216.0, 5.0~542.0和5.0~778.0 μmol/L; 检出限分别为0.17, 0.30和0.30 μmol/L. 将该修饰电极用于实际样品(血清和尿液)中UA, XA和HX的同时测定, 加标回收率为98.4%~105.2%.     

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.     

Graphitic Carbon Nitride Microspheres Supportedα-FeO(OH)Hybrids for Visible Light Photodegradation of MO

Graphitic carbon nitride(g-C3N4)microspheres supported a-FeO(OH)hybrids[α-FeO(OH)/g-C3N4]were prepared by means of a self-assembly method in deionized water.By UV-visible diffiise reflectance spectroscopy,it has been confirmed thatα-FeO(OH)/g-C3N4 has a wider absorption range thanThe feature ofα-FeO(OH)/g-C3N4 can be attributed to the efficient separation of the electron-hole pairs with photoluminescence spectra.The degradation rate of methyl orange(MO)is up to 99%under the optimal conditions of 110 min,initial concentration of 30 mg/L,anα-FeO(OH)/g-C3N4 dosage of 15 mg as well as visible light.The mechanism for this photocatalytic reaction was proposed,with hydroxyl radicals being a major active catalytic species.     

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.     

类石墨烯C3N4纳米片光催化分解水制氢中的量子限域效应

从层状化合物获得的纳米片是一类新型纳米结构材料,这种二维各向异性的纳米甚至亚纳米级的材料具有独特的物理化学性能,其中最好的一个例证就是从石墨烯C₃N₄到石墨烯C₃N₄纳米片的转变。通过高温氧化热刻蚀方法将体相g-C₃N₄剥离成g-C₃N₄纳米片,应用于染料敏化可见光分解水产氢,表现出了较体相g-C₃N₄高于2.6倍的产氢速率。通过X射线衍射（XRD）、傅里叶变换红外（FTIR）光谱、扫描电子显微镜（SEM）、Brunauer-Emmett-Teller（BET）、荧光光谱和光电化学等表征研究了g-C₃N₄纳米片的结构及曙红（EY）和g-C₃N₄纳米片之间的电子迁移过程。热剥离后的g-C₃N₄纳米片具有较高的比表面积,不仅可以更为有效地吸附染料分子,还因其量子限域效应大大增强了光生电荷的分离效率和电子转移效率,改善了电子沿平面方向的传输能力以及光生载流子的寿命,从而显著提高g-C₃N₄纳米片的光催化产氢活性。     

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.     

可见光诱导提升Pt/g-C3N4纳米片甲酸氧化性能的研究

以半导体材料类石墨氮化碳纳米片(g-C₃N₄纳米片)为载体,通过微波-多元醇法构筑了Pt/g-C₃N₄纳米片催化剂. 通过TEM、XRD、XPS、紫外-可见吸收光谱等方法对Pt/g-C₃N₄纳米片催化剂的粒径尺寸、组成、结构、光学等性质进行分析. 通过对比可见光照和暗室条件下的甲酸电氧化活性,Pt/g-C₃N₄纳米片催化剂在可见光照射下展现出良好的催化性能. 该性能的提高一方面可能是由于g-C₃N₄纳米片在可见光照射下加速了电子从Pt转移给g-C₃N₄纳米片,Pt处于“电子匮乏”状态,可削弱CO与Pt之间的化学键能,减弱CO在Pt表面的吸附能力,促进了CO的氧化,提高了催化剂抗中毒能力;另一方面,g-C₃N₄纳米片在光照条件下分离出的空穴可有效氧化甲酸分子,提高甲酸氧化活性. 因此,可见光条件下可有效提高Pt/g-C₃N₄纳米片催化剂甲酸催化氧化活性,这为直接甲酸燃料电池的发展提供了新思路.     

高活性位点密度Fe-N共掺杂碳纳米片的制备及氧还原性能

从三聚氰胺和均苯四甲酸酐单体出发, 通过熔融盐法合成了三嗪结构聚酰亚胺纳米片, 借助类石墨相氮化碳(g-C₃N₄)与铁离子的配位作用, 经高温热处理形成了高效掺杂的Fe-N/C催化剂. 研究结果表明, 该催化剂为表面粗糙的纳米片结构, 比表面积高达1794 m²/g. 通过g-C₃N₄的引入和含量的调控, 催化剂中铁元素的掺杂量最高可达1.13%(摩尔分数), 为未引入g-C₃N₄的3.3倍, 其原因可归结于g-C₃N₄配位锚定了铁离子, 其较强的配位作用可以避免高温热处理时铁元素的迁移和聚集. 该催化剂在酸性条件下氧还原反应半波电位为0.79 V, 10000周加速测试后的半波电位衰减了30 mV, 表现出较好的氧还原活性.     

Facile and efficient fabrication of g-C3N4 quantum dots for fluorescent analysis of trace copper(II) in environmental samples

A facile and efficient fabrication of g-C₃N₄ quantum dots with highly fluorescent based on recrystallization and ultrasonic exfoliation was presented. The obtained g-C₃N₄ QDs was successfully applied to the determination of trace Cu(II) in different environmental water samples.     

Surface molecular imprinting on g-C3N4 photooxidative nanozyme for improved colorimetric biosensing

Molecular imprinting on g-C₃N₄ leads to an over 1000-fold alleviation in matrix-interference from serum samples.     

单层石墨相氮化碳负载Pt4团簇吸附O2的第一性理论研究

采用第一性原理密度泛函理论结合周期性平板模型模拟研究了Pt₄团簇吸附单层石墨相氮化碳(g-C₃N₄)的几何结构和电子性质,以及氧气在其表面上的吸附行为。同时,对比分析了氧气在纯净的石墨相氮化碳和Pt₄团簇上的吸附行为。计算结果表明, Pt₄团簇吸附在3-s-三嗪环石墨相氮化碳表面,并与四个边缘氮原子成键,形成两个六元环时为最稳定构型。Pt₄团簇倾向于吸附在三嗪环石墨相氮化碳的空位并与邻近三个氮原子成键。由于Pt与N原子较强的杂化作用,以及金属与底物之间较多电子转移增强了Pt₄团簇吸附g-C₃N₄的稳定性。另外,对比分析了氧气在纯净的g-C₃N₄和金属吸附的g-C₃N₄上吸附行为,发现金属原子的加入促进了电子转移,同时拉长了O―O键长。Pt₄吸附3-s-三嗪环g-C₃N₄比Pt₄吸附三嗪环g-C₃N₄表现出微弱的优势,表现出明显的基底扭曲以及较大的吸附能。这些结果表明,化学吸附通过调节电子结构和表面性质增强催化性能的较好方法。     

磷钨酸功能化氮化碳的制备及其氧化脱硫研究

以磷钨酸和氮化碳为原料,合成磷钨酸功能化的氮化碳(g-C₃N₄/HPW),并采用XRD、SEM、FT-IR对其结构进行表征。以g-C₃N₄/HPW为催化剂,过氧化氢作为氧化剂,咪唑氟硼酸盐为萃取剂氧化萃取一体法脱除模拟油中的二苯并噻吩(DBT)。考察了反应温度、催化剂加入量、双氧水加入量、萃取剂加入量、硫化物类型等因素对脱硫效果的影响。结果表明,在模拟油为5 mL,g-C₃N₄/HPW为0.02 g,H₂O₂加入量为1.0 mL,BF₄ 为1.5 mL,反应温度70 ℃,反应120 min的条件下,DBT的转化率可达到93%。反应体系循环使用4次催化剂的活性没有明显的降低。     

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.     

三元金属硫化物-石墨相氮化碳异质结催化剂的制备及光催化性能

以双氰胺、醋酸锌、钼酸铵、醋酸镉和硫化钠为原料,采用水热法合成了一系列Zn-Mo共掺杂CdS(Zn-Mo-CdS),并与g-C₃N₄组成异质结催化剂(Zn-Mo-CdS/g-C₃N₄)。采用X射线衍射光谱(XRD)、紫外-可见(UV-Vis)光谱、电感耦合等离子体-原子发射光谱(ICP-AES)、电化学阻抗谱(EIS)、X光电子能谱(XPS)等分析手段对制备的催化剂进行了表征。结果表明, Zn-Mo-CdS与g-C₃N₄之间紧密结合并形成异质结,促进界面电荷迁移,抑制光生电子-空穴对的复合。以可见光下降解染料罗丹明B (RhB)为探针反应考察了催化剂性能。结果表明, Zn-Mo-CdS/g-C₃N₄异质结催化剂的光催化性能与单纯g-C₃N₄、Zn-Mo-CdS及双金属硫化物/g-C₃N₄异质结催化剂相比均有大幅度提高,质量比m(Zn-Mo-CdS)/m(g-C₃N₄) = 4 : 1时制备的异质结催化剂表现出最大的降解速率常数,是单纯g-C₃N₄和Zn-Mo-CdS的30倍和10倍。不仅Zn-Mo-CdS,其他三元金属复合硫化物如Mo-Ni-CdS和Ni-Sn-CdS与g-C₃N₄之间也能有效构筑异质结,促进电子-空穴对的分离和催化性能提升。     

Z型光催化剂Sb2WO6/g-C3N4的制备及光催化性能

通过水热反应合成了Sb₂WO₆改性的g-C₃N₄复合材料(Sb₂WO₆ /g-C₃N₄). 通过X射线衍射(XRD)、 扫描电子显微镜(SEM)、 紫外-可见漫散射反射光谱(UV-Vis DRS)和光致发光光谱(PL)等表征了样品的性质. 结果表明, Sb₂WO₆在g-C₃N₄的表面上生长, 并且复合材料光吸收能力有一定的增强, 光生电子-空穴的重组率降低. 通过罗丹明B(RhB)的光降解评价了Sb₂WO₆/g-C₃N₄复合材料的光催化性能. 结果表明, 模拟日光下Sb₂WO₆质量分数为10%的Sb₂WO₆/g-C₃N₄复合材料在60 min内对RhB的降解率为99.3%, 高于纯g-C₃N₄和Sb₂WO₆. Sb₂WO₆/g-C₃N₄复合材料的这种高度增强的光催化活性主要归因于强的界面相互作用促进了光生电子-空穴分离和迁移. 添加自由基清除剂的实验结果表明, ·O^2-和h⁺是光催化反应中的主要活性物质. Sb₂WO₆/g-C₃N₄复合材料在几个反应周期内表现出优异的稳定性. 根据实验结果提出了一种可能的Z型光催化机理.     

Enhanced Visible-light Photocatalytic Activity of g-C3N4/Nitrogen-doped Graphene Quantum Dots/TiO2 Ternary Heterojunctions for Ciprofloxacin Degradation with Narrow Band Gap and High Charge Carrier Mobility

Limited visible-light absorption and high recombination rate of photogenerated charges are two main drawbacks in g-C₃N₄-based photocatalysts. To solve these problems, g-C₃N₄/nitrogen-doped graphene quantum dots (NGQDs)/TiO₂ ternary heterojunctions were facilely prepared via a one-step calcining method. The morphology, structure, optical and electrochemical properties of g-C₃N₄/NGQDs/TiO₂ were characterized and explored. The optimal g-C₃N₄/NGQDs/TiO₂ composite exhibits enhanced photocatalytic degradation performance of ciprofloxacin (CIP) compared with the as-prepared g-C₃N₄, TiO₂(P25) and g-C₃N₄/TiO₂ heterojunction under visible light irradiation. The apparent rate constant of the composite is around 6.43, 4.03 and 2.30 times higher than those of g-C₃N₄, TiO₂ and g-C₃N₄/TiO₂, respectively. The enhanced photocatalytic efficiency should be mainly attributed to the improvement of light absorption and charge separation and transfer efficiency, originating from the narrow band gap and high charge carrier mobility. The active species trapping experiments results showed that the h⁺ and ^·O₂^- were the main active species in the degradation process. A possible photocatalytic reaction mechanism of the g-C₃N₄/NGQDs/TiO₂ composite for the enhanced degradation of CIP under visible light irradiation was also proposed.     

介孔氮化碳材料合成的研究进展

石墨相氮化碳(g-C₃N₄)是一种新型的无金属材料,因其具有众多特殊的理化性质,在多相催化、光催化、燃料电池和气体储存等领域显示出了潜在的应用前景。与直接热聚合法制得的块状g-C₃N₄相比,介孔g-C₃N₄拥有高比表面和丰富的介孔孔道,能暴露更多的表面活性位,继而提升其在催化反应等应用方面的性能。热聚合法是合成g-C₃N₄的最为便利的方法。其中,热聚合法合成介孔g-C₃N₄的工艺分为硬模板法、软模板法和无模板法。本文对近十年来国内外这三种合成工艺的研究进展进行了综述。特别是针对硬模板法,从前驱体合成机理、产品理化性质等多角度评述了硬模板法合成介孔g-C₃N₄的关键问题。此外,针对新型的软模板法和无模板法进行了介绍,并与硬模板法进行了细致的对比和讨论。最后,对介孔g-C₃N₄合成工艺的未来发展趋势进行了展望。     

Ni,Co基硒化物修饰g-C3N4光催化产氢研究

Developing novel and efficient catalysts is a significant way to break the bottleneck of low separation and transfer efficiency of charge carriers in pristine photocatalysts. Here, two fresh photocatalysts, g-C₃N₄@Ni₃Se₄ and g-C₃N₄@CoSe₂ hybrids, are first synthesized by anchoring Ni₃Se₄ and CoSe₂ nanoparticles on the surface of well-dispersed g-C₃N₄ nanosheets. The resulting materials show excellent performance for photocatalytic in situ hydrogen generation. Pristine g-C₃N₄ has poor photocatalytic hydrogen evolution activity (about 1.9 μmol·h^-1) because of the rapid recombination of electron-hole pairs. However, the hydrogen generation activity is well improved after growing Ni₃Se₄ and CoSe₂ on the surface of g-C₃N₄, owing to the unique effect of these selenides in accelerating the separation and migration of charge carriers. The hydrogen production activities of G-C₃N₄@Ni₃Se₄ and g-C₃N₄@CoSe₂ are about 16.4 μmol·h^-1 and 25.6 μmol·h^-1, which are 8-fold and 13-fold that of pristine g-C₃N₄, respectively. In detail, coupling Ni₃Se₄ and CoSe₂ with g-C₃N₄ greatly improves the light absorbance density and extends the light response region. The photoluminescence intensity of the photoexcited Eosin Y dye in the presence of g-C₃N₄@Ni₃Se₄ and g-C₃N₄@CoSe₂ is weaker than that in the presence of pure g-C₃N₄. On the other hand, the upper limit of the electron-transfer rate constants in the presence of g-C₃N₄@Ni₃Se₄ and g-C₃N₄@CoSe₂ is greater than that in the presence of pure g-C₃N₄. Among the g-C₃N₄@Ni₃Se₄@FTO, g-C₃N₄@CoSe₂@FTO, and g-C₃N₄@FTO electrodes, the g-C₃N₄@FTO electrode has the lowest photocurrent density and the highest electrochemical impedance, implying that the introduction of CoSe₂ and Ni₃Se₄ onto the surface of g-C₃N₄ enhances the separation and transfer efficiency of photogenerated charge carriers. In other words, the formation of two star metals selenide based on g-C₃N₄ can efficiently inhibit the recombination of photogenerated charge carriers and accelerate photocatalytic water splitting to generate H₂. Meanwhile, the right shift of the absorption band edge effectively reduces the transition threshold of the photoexcited electrons from the valence band to the conduction band. In addition, the more negative zeta potential for the g-C₃N₄@Ni₃Se₄ and g-C₃N₄@CoSe₂ catalysts as compared with that for pure g-C₃N₄ leads to a notable enhancement in the adsorption of protons by the sample surface. Moreover, the results of density functional theory calculations indicate that the hydrogen adsorption energy of the N sites in g-C₃N₄ is -0.22 eV; further, the hydrogen atoms are preferentially adsorbed at the bridge site of two selenium atoms to form a Se―H―Se bond, and the adsorption energy is 1.53 eV. In-depth characterization has been carried out by transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, transient photocurrent measurements, and Fourier transform infrared spectroscopy; the results of these experiments are in good agreement with one another.