Novel magnetically separable g-C3N4/Fe3O4/Ag3PO4/Co3O4 nanocomposites: Visible-light-driven photocatalysts with highly enhanced activity

In this study, a series of novel quaternary g-C₃N₄/Fe₃O₄/Ag₃PO₄/Co₃O₄ nanocomposites were fabricated. The prepared nanocomposites were characterized by XRD, EDX, SEM, TEM, UV-DRS, FT-IR, PL, TG, and VSM methods to gain insight about structure, purity, morphology, optical, thermal, and magnetic properties. Photocatalytic activity of the samples was investigated under visible-light irradiation by degradations of rhodamine B, methylene blue, methyl orange, and phenol as four organic pollutants. The highest photocatalytic degradation efficiency was observed when the sample calcined at 300 °C for 2 h with 20 wt% of Co₃O₄. The photocatalytic activity of this nanocomposite is almost 16.8, 15.7, 4.6, and 5.1 times higher than those of the g-C₃N₄, g-C₃N₄/Fe₃O₄, g-C₃N₄/Fe₃O₄/Ag₃PO₄ (20%), and g-C₃N₄/Fe₃O₄/Co₃O₄ (20%) samples in photodegradation of rhodamine B, respectively. Finally, on the basis of the energy band positions, the mechanism of enhanced photocatalytic activity was discussed.     

High performance magnetically recoverable g-C3N4/Fe3O4/Ag/Ag2SO3 plasmonic photocatalyst for enhanced photocatalytic degradation of water pollutants

The g-C₃N₄/Fe₃O₄/Ag/Ag₂SO₃ nanocomposites have been successfully fabricated by facile refluxing method. The as-obtained products were characterized by XRD, EDX, SEM, TEM, UV–vis DRS, FT–IR, TGA, PL, and VSM techniques. The results suggest that the Ag/Ag₂SO₃ nanoparticles have anchored on the surface of g-C₃N₄/Fe₃O₄ nanocomposite, showing strong absorption in the visible region. The evaluation of photocatalytic activity indicates that for the g-C₃N₄/Fe₃O₄/Ag/Ag₂SO₃ (40%) nanocomposite, the degradation rate constant was 188 × 10^?4 min^?1 for rhodamine B, exceeding those of the g-C₃N₄ (16.0 × 10^?4 min^?1) and g-C₃N₄/Fe₃O₄ (20.2 × 10^?4 min^?1) by factors of 11.7 and 9.3, respectively. The results showed that the nanocomposite prepared by refluxing for 120 min has the superior photocatalytic activity and its activity decreased with rising the calcination temperature. The trapping experiments confirmed that superoxide ion radical was the main active species in the photocatalytic degradation process. Also, it was demonstrated that the magnetic photocatalyst has considerable activity in degradation of one more dye pollutant. Finally, the reusability of the photocatalyst was evaluated by five consecutive catalytic runs. This work may open up new insights into the utilization of magnetically separable nanocomposites and provide new opportunities for facile fabrication of g-C₃N₄-based plasmonic photocatalysts.     

Novel ternary g-C3N4/Fe3O4/MnWO4 nanocomposites: Synthesis,characterization, and visible-light photocatalytic performance for environmental purposes

The g-C₃N₄/Fe₃O₄/MnWO₄ nanocomposites were prepared by a refluxing-calcination procedure. Visible-light-induced photocatalytic experiments showed that the g-C₃N₄/Fe₃O₄/MnWO₄ (10%) nanocomposite has excellent ability to degrade a range of contaminants including rhodamine B, methylene blue, methyl orange, and fuchsine, which is about 7, 10, 25, and 31 times of the g-C₃N₄ photocatalyst, respectively. Reactive species trapping experiments revealed that superoxide anion radicals play major role in the photodegradation reaction of rhodamine B (RhB). After the treatment process, the utilized photocatalyst was magnetically recovered and reused with negligible loss in the photocatalytic activity, which is vital in the photocatalytic processes. Finally, a mechanism was proposed for the enhanced interfacial carrier separation and transfer and the improved photocatalytic performance.     

SnO2/g-C3N4 photocatalyst with enhanced visible-light photocatalytic activity

Visible light-responsive SnO₂/g-C₃N₄ nanocomposite photocatalysts were prepared by ultrasonic-assisting deposition method with melamine as a g-C₃N₄ precursor. The as-prepared photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy, Fourier transform infrared spectra and photoluminescence emission spectra. The photocatalytic activities of the samples were evaluated by monitoring the degradation of methyl orange solution under visible light irradiation (wavelength ≥400 nm). The results show that the SnO₂ nanoparticles with the size of 2–3 nm are dispersed on the surface of g-C₃N₄ evenly in SnO₂/g-C₃N₄ nanocomposites. The visible-light photocatalytic activity of SnO₂/g-C₃N₄ nanocomposites is much higher than that of pure g-C₃N₄, and increases at first and then decreases with the increment of the content of g-C₃N₄ in the nanocomposites. The visible-light photocatalytic mechanism of the investigated nanocomposites has been discussed.     

Co_3O_4/mpg-C_3N_4催化剂的制备及其可见光催化性能研究

采用浸渍法制备了载钴介孔石墨相氮化碳(Co3O4/mpg-C3N4)催化剂,并对其进行X射线衍射(XRD),红外光谱(FT-IR),N2吸附脱附,紫外漫反射光谱(UV-vis DRS)和光生电流的表征。结果显示,Co3O4的引入提高了mpg-C3N4的光吸收性能,利于其表面光生电子和空穴的分离。将制得的Co3O4/mpg-C3N4用于可见光催化降解水中的亚甲基蓝(MB),其催化效率远高于mpg-C3N4,且最佳的钴负载量为3%。     

Significantly enhanced photocatalytic hydrogen production performance of g-C3N4/CNTs/CdZnS with carbon nanotubes as the electron mediators

The electron mediator can effectively improve the performance of the direct Z-scheme heterojunction photocatalysts.However,it is still a great challenge to select cheap and efficient electron mediators and to design them into the Z-scheme photocatalytic system.In the present paper,the g-C3N4/CNTs/CdZnS Z-scheme photocatalyst was prepared using carbon nanotubes (CNTs) as the electron mediators,and its photocatalytic hydrogen production performance was studied.Compared with single-phase g-C3N4,CdZnS and biphasic g-C3 N4/CdZnS photocatalysts,the photocatalytic hydrogen production performance of the prepared g-C3N4/CNTs/CdZnS has been significantly enhanced.Meanwhile,g-C3N4/CNTs/CdZnS possesses very good photocatalytic hydrogen production stability.The enhanced photocatalytic hydrogen production performance of g-C3 N4/CNTs/CdZnS is attributed to the fact that CNTs,as an electron mediator,can accelerate the recombination of the photogenerated holes in the valence band of g-C3N4 and the photogenerated electrons in the conduction band of CdZnS,which makes the g-C3N4/CNTs/CdZnS Z-scheme photocatalyst be easier to escape the photogenerated electrons,increases the concentration of the photogenerated carriers and prolongs the lifetime of the photogenerated carriers.This work provides a theoretical basis for the further development and design of CNTs as the intermediate electron mediator of the Z-scheme heterojunction photocatalyst.     

Fabrication of highly efficient g-C3N4/ZnO/Fe2O3 ternary composite with enhanced photocatalytic activity under visible light irradiation

Journal of Materials Science: Materials in Electronics - The development of an efficient and photostable heterostructured photocatalyst has attracted a great deal of attention for the degradation...     

Magnetically recoverable highly efficient visible-light-active g-C3N4/Fe3O4/Ag2WO4/AgBr nanocomposites for photocatalytic degradations of environmental pollutants

Herein, magnetically recoverable g-C₃N₄/Fe₃O₄/Ag₂WO₄/AgBr (gCN/M/AgW/AgBr) nanocomposites, as greatly efficient visible-light-active photocatalysts, were fabricated by successive decoration of Fe₃O₄, Ag₂WO₄, and AgBr over g-C₃N₄ (gCN) and they were characterized by XRD, EDX, SEM, TEM, HRTEM, UV–vis DRS, FT-IR, PL, TG, and VSM analysis. Visible-light-induced photocatalytic performances were studied by degradations of RhB, MB, MO, and fuchsine pollutants. It was confirmed that the nanocomposites are effective in the reduction of e^?/h⁺ recombination through the matched interactions between energy bands of gCN, Fe₃O₄, Ag₂WO₄, and AgBr semiconductors. The highest photocatalytic degradation efficiency was observed for the gCN/M/AgW/AgBr (30%) nanocomposite when it was refluxed for 30?min. Activity of this nanocomposite is almost 21, 41, 94, and 10-folds greater than those of the gCN toward the degradations of RhB, MB, MO, and fuchsine pollutants, respectively. Additionally, a mechanism for the superior photocatalytic performances was proposed using reactive species scavenging experiments and characterization results.     

Probing charge transfer of NiCo2O4/g-C3N4 photocatalyst for hydrogen production

Quantum dots/two-dimensional(0D/2D)semiconductor photocatalysts demonstrate wide solar light ab-sorption region and high charge transfer efficiency.However,the relation between the interfacial electric field and the charge transfer during the photocatalytic hydrogen production process is still unclear.Here,we construct NiCo2O4 quantum dots(QDs)and NiCo2O4 nanoparticles(NPs)anchored with 2D g-C3N4(CN)to form NiCo2O4-QDs/CN and NiCo2O4-NPs/CN heterojunctions.The hydrogen production rate of CN loaded with NiCo2O4 QDs is about 3 times higher than that of CN loaded with NiCo2O4 NPs.The electric field intensity at the NiCo2O4-QDs/CN interface is calculated to be about 15,600 V cm-2,about 9 times higher than that of NiCo2O4-NPs/CN,which could effectively drive the electrons of CN to flow toward NiCo2O4 QDs,promoting photocarriers separation and hence greatly improving the photocatalytic per-formance.This work provides a method to understand the relationship between interfacial electric field strength and photogenerated charges of heterostructure photocatalysts.     

Fe3O4/BSA纳米磁性复合颗粒的磁响应性能

利用化学液相共沉淀法制备出不同尺寸、具有超顺磁性的纳米磁性Fe3O4/BSA颗粒,经分散后包覆蛋白使其具备良好的生物兼容性,该颗粒可长期、稳定地分散在溶液中。在外加交变磁场(414kA/m,50Hz)下纪录不同颗粒的浊度变化率,并利用光透射性可即时测得介质中浑浊程度与时间的关系,结合浊度-浓度拟合曲线,计算出在外加磁场作用下,磁性纳米复合颗粒对外加磁场的响应程度,半定量计算出相同时间下不同尺寸的微粒吸附在管壁上的质量百分比。结果显示,稳定在介质中的纳米磁性颗粒在外加磁场后,磁响应性随颗粒尺寸增大而增大,颗粒大小分别为10、108和210nm,所对应的磁响应性分别为6%、10%和12%;在外加磁场30s后,该磁性纳米复合颗粒在管壁附着的质量百分比分别为39.9%、70.4%及86.7%。     

Synthesis of Z-scheme g-C3N4/Gd-doped Bi2WO6 heterojunction with enhanced visible-light photodegradation of organic dyes

Herein, we prepared the g-C₃N₄/Gd-doped Bi₂WO₆ Z-scheme heterojunction (BCN) composites by a simple hydrothermal method. The composites were investigated by SEM (EDX), TEM, XRD, XPS, UV–Vis DRS and PL analysis. The photocatalytic performance of composites was envaulted by degrading methylene blue (MB) under the irradiation of a 300 W mercury lamp. The results demonstrated that coupling g-C₃N₄ and doping Gd ³⁺ effectively enhanced the photocatalytic efficiency of pure Bi₂WO₆. The 92% of MB was degraded within 120 min by optimal 0.15–100 BCN sample, being 1.61 times as that of Bi₂WO₆. The greatly enhanced performance of 0.15–100 BCN was due to the synergistic effect of Gd ³⁺ doping and g-C₃N₄ coupling, which maintained high redox capacity. According to the experiment of capture active species, Z-scheme charge transfer mechanism was also deduced. This study may provide an efficient and green method for the treatment of dyestuff industrial wastewater.

     

Fly ash cenospheres as multifunctional supports of g-C3N4/N-TiO2 with enhanced visible-light photocatalytic activity and adsorption

The ternary composites of g-C₃N₄/N-TiO₂/FACs (FAC: Fly Ash Cenospheres) were synthesized by an in-situ hydrolysis method to improve the photocatalytic activity and their stability. When TiO₂ was anchored on FAC, it was easily to be separated from the aqueous solution and could be repeatedly utilized. In the present experiments, the degradation rate remained for more than 68% even after the composite reused for seven times. The band gap of g-C₃N₄/N-TiO₂/FAC was 2.75?eV, which might be owing to the synergistic effect between N-TiO₂ and g-C₃N₄. The composite of g-C₃N₄/N-TiO₂/FAC had an ideal activity of 72.2% under visible light illumination for 180?min. It was about 1.3 times of N-TiO₂/FAC and 3.5 times of g-C₃N₄. The synergistic effect of SiO₂, Fe₂O₃ and TiO₂ components resulted to the improvement of photocatalytic performance.     

Fabrication of magnetic Fe3O4/C/TiO2 composites with nanotube structure and enhanced photocatalytic activity

Magnetic hybrid photocatalysts containing TiO₂ nanotube as outer catalytic layer and Fe₃O₄ as the core, with an amorphous carbon intermediate layer, were synthesised, characterised and applied to degradation of phenol under Xenon lamp irradiation. For the composite, Fe₃O₄/C microspheres were surrounded by anatase TiO₂ nanotubes with a diameter of ～8–10?nm. Photocatalytic performance of the Fe₃O₄/C/TiO₂ nanotube (FCT-NT) composites was also evaluated and showed enhanced activity superior to commercial P25 and homemade TiO₂ particles. The outstanding photocatalytic performance of FCT-NT sample could be attributed to its improved surface area and enhanced capability of optical absorption. Notably, the novel photocatalyst showed excellent magnetic behaviour and could be efficiently separated and collected from the wastewater.     

Multiple heterojunction system of Bi2MoO6/WO3/Ag3PO4 with enhanced visible-light photocatalytic performance towards dye degradation

Multiple heterojunction system of Bi₂MoO₆/WO₃/Ag₃PO₄ was designed via constructing binary heterojunction Bi₂MoO₆/WO₃, followed by the deposition of nano-Ag₃PO₄ on the surface of Bi₂MoO₆/WO₃. Various techniques were employed to characterize the properties of the as-prepared catalytic system. In this study, the decomposition efficiency of C.I. reactive blue 19 (RB-19) was used as a measure of photocatalytic activity and the Bi₂MoO₆/WO₃/Ag₃PO₄ composite exceeded its stand-alone components (pristine Ag₃PO₄, WO₃/Ag₃PO₄ and Bi₂MoO₆/Ag₃PO₄) by 3.16 times, 2.63 times and 1.75 times, respectively. The photocatalytic tests implied that the construction of multiple heterojunction could achieve efficient separation of photo-generated electrons and holes. A possible photocatalytic mechanism for Bi₂MoO₆/WO₃/Ag₃PO₄ system was also proposed according to the results of trapping experiments.     

Constructing BiOBr/g-C3N4/Bi2O2CO3 Z-scheme photocatalyst with enhanced photocatalytic activity

Journal of Materials Science: Materials in Electronics - In this work, the novel camellia-structured double Z-scheme BiOBr/g-C3N4/Bi2O2CO3 was simply prepared by a hydrothermal method. XRD, FTIR,...     

Fe3O4纳米粒子修饰碳纳米管的制备及其磁学性能（英文）

通过FeCl2.4H2O和FeCl3.6H2O混合共沉淀,合成平均粒径为6 nm和10 nm的Fe3O4纳米粒子。然后将两种Fe3O4纳米粒子分别与经HNO3氧化处理的多壁碳纳米管(MWCNTs)置于乙醇水溶液(水和乙醇的体积比为1∶1)中,在超声波作用下制备Fe3O4/MWCNT复合材料。用高分辨透射电子显微镜、X-射线光电子能谱、振动样品磁强计、X射线衍射仪、热重分析仪对所制备的Fe3O4/MWCNT复合材料进行表征。结果表明:由6 nm和10 nm Fe3O4纳米粒子所制备的Fe3O4/MWCNT复合材料中,Fe3O4的质量分数分别为26.65%和29.3%,相应的磁饱和强度分别为16.5 emug-1和7.5 emug-1。     

Laser-assisted preparation of C3N4/Fe2O3/Au nanocomposite: a magnetic reusable catalyst for pollutant degradation

Clean Technologies and Environmental Policy - Assorted common contaminants namely organic dyes and nitro compounds are generated by various industries and have caused alarming problems for the...