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Improvement in Photocatalytic Properties of Synthesized Nano-structured ZnO in Magnetic Water and in Presence of Static Magnetic Field
摘要： This article presents the effects of magnetic water (MW), and static magnetic field (SMF) compared to non-magnetic water (NMW) on the synthesis and photocatalytic efficiency of ZnO nano-structures. ZnO nano-structures are synthesized in the three methods; in the MW (110 mT), in the presence of a SMF (75 mT) and NMW. The Different analysis is performed on the synthesized materials utilizing UV-visible spectrometer, XRD and FESEM. Then, the photocatalytic activities of the ZnO samples are comparatively studied. The results of the XRD analysis show that all the three nano-structures of ZnO are in hexagonal phase. The average size of the synthesized nano-structure ZnO crystals in the presence of SMF and MW are 10% and 19% bigger than the synthesized sample in the NMW. The FESEM images show the synthesized ZnO samples in the NMW, and the MW has a rod-like structure, but in the presence of SMF looks to be agglomerated. Photocatalytic activity of synthesized ZnO in the presence of the SMF and the MW are respectively 26% and 24% higher than the synthesized ZnO in NMW. Also, on comparing the performance of these ZnO nano-structures with the micron-sized sample, around 58% improvement in photocatalytic activity is observed.
关键词： ZnO,magnetic water,photocatalytic activity,crystal growth,hexagonal,nano-rod
更新于2025-09-11 14:15:04
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Fabrication of Ag3VO4 decorated phosphorus and sulphur co-doped graphitic carbon nitride as a high-dispersed photocatalyst for phenol mineralization and E. Coli disinfection
摘要： In this work, we have successfully anchored Ag3VO4 (AV) onto P and S co-doped g-C3N4 (PSGCN) to prepare high-dispersible AV/PSGCN photocatalyst via a deposition-precipitation method. The P and S co-doped g-C3N4 was synthesized via thermal polycondensation using hexachlorotriphosphazene (HCCP) and thiourea as precursors. AV/PSGCN was characterized using various spectral techniques. The atomic force analysis indicated that the thickness of AV/PSGCN was less than 3.0 nm. The zeta potential and Tyndall effect experiments ascertained formation of the well-dispersed suspension of AV/PSGCN in water. The co-doping resulted in lowering optical band gap of g-C3N4. The photoluminescence and electrochemical impedance analysis indicated suppression in recombination of photogenerated electron and hole pairs in AV/PSGCN. The photodegradation of phenol followed pseudo-first order kinetics. Hydroxyl radicals and holes were the two main reactive species for photodegradation of phenol. The COD, HPLC and LC-MS analyses confirmed mineralization of phenol in 6 h. Unlike conventional slurry type photo-reactors, AV/PSGCN was not magnetically agitated during photocatalytic reactions. AV/PSGCN exhibited significant antibacterial activity for E.Coli disinfection. The photodegradation of phenol and bacterial disinfection occurred through hole and hydroxyl radical formation mechanism.
关键词： Phenol degradation,Enhanced photocatalytic activity,Heterojunction formation,Ag3VO4,Antibacterial activity,Co-doped g-C3N4
更新于2025-09-10 09:29:36
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Photocatalytic Activity: Experimental Features to Report in Heterogeneous Photocatalysis
摘要： Heterogeneous photocatalysis is a prominent area of research with major applications in solar energy conversion, air pollution mitigation, and removal of contaminants from water. A large number of scienti?c papers related to the photocatalysis ?eld and its environmental applications are published in different journals specializing in materials and nanomaterials. However, many problems exist in the conception of papers by authors unfamiliar with standard characterization methods of photocatalysts as well as with the procedures needed to determine photocatalytic activities based on the determination of “apparent quantum ef?ciencies” within a wavelength interval or “apparent quantum yields” in the case of using monochromatic light. In this regard, an astonishing number of recent research articles include claims of highly ef?cient (photo)catalysts or similar terms about materials with superior or enhanced ef?ciency for a given reaction without proper experimental support. Consequently, the comparison of the ef?ciencies of photocatalysts may result as being meaningless, especially when reports are only based on expressions determining (1) a reaction rate per weight of catalyst or its surface area, (2) quantum ef?ciencies or quantum yields, and (3) turnover frequencies or turnover numbers. Herein, we summarize the standards needed for reporting valuable data in photocatalysis and highlight some common discrepancies found in the literature. This work should inform researchers interested in reporting photocatalysis projects about the correct procedures for collecting experimental data and properly characterizing the materials by providing examples and key supporting literature.
关键词： photocatalytic activity,apparent quantum ef?ciency,photocatalytic ef?ciency,rate per weight,heterogeneous photocatalysis
更新于2025-09-10 09:29:36
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Effective Removal of Emerging Dissolved Cyanotoxins from Water using Hybrid Photocatalytic Composites
摘要： Harmful algal blooms are occurring more frequently in fresh water throughout the world. Certain cyanobacteria can produce and release potent toxic compounds, known as cyanotoxins, such as microcystins, cylindrospermopsin, saxitoxin, and anatoxin-a, and as such they have become a human and environmental health concern. Hybrid photocatalytic composites (HPCs) comprising carbon nanotubes on the surface of TiO2 nanotubes were designed in this study. The HPCs have a selective adsorption capacity to cyanotoxins and provide photocatalytic activity to produce reactive oxygen species for the degradation of cyanotoxins. HPCs with 5.2 mg carbon nanotubes/cm2 showed an excellent removal efficiency of microcystins-LR (> 95%) at 55.6 L/m2/hr/bar. The HPCs more efficiently removed the relatively larger and more hydrophobic cyanotoxins (i.e., microcystin-LR) than the relatively smaller and more hydrophilic compounds (such as cylindrospermopsin, saxitoxin, and anatoxin-a). With a further increased in the carbon nanotube content to 8.6 mg/cm2, the adsorption capacity of the HPCs for cyanotoxins increased to 70.6% for MC-LR. However, there was significant decrease in the photocatalytic activity of the HPCs for production of reactive oxygen species, and consequently a decrease in the degradation of cyanotoxins. It is considered that this device could be used to provide complete rejection of particles and pathogens, and also to significantly reduce trace organic compounds and harmful algal toxins in emergency water supplies.
关键词： Adsorption,Harmful algal blooms,Cyanotoxins,Photocatalytic activity,Reactive oxygen species,Hybrid photocatalytic composites
更新于2025-09-10 09:29:36
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Two-step Synthesis of Laminar Vanadate via a Facile Hydrothermal Route and Enhancing the Photocatalytic Reduction of CO2 into Solar Fuel through Tuning the Oxygen Vacancies by in situ Vacuum Illumination Treatment
摘要： Monoclinic LaVO4, tetragonal CeVO4 and monoclinic Pb2V2O7 with laminar structures composed of nanosheets have been successfully fabricated using a two-step facile hydrothermal route. The narrow-bandgap LaVO4, CeVO4 and Pb2V2O7 vanadate exhibited photocatalytic activity towards the photoreduction of CO2 into C2H5OH in the liquid phase. The existence of oxygen vacancies on LaVO4 surface further enhanced the photocatalytic activity for photoreduction of CO2 into CO in gas phase, which can be easily obtained using a vacuum illumination treatment. The EPR, PL and FTIR results indicated that oxygen vacancies are beneficial to the separation of electrons by prolonging the lifetime of the photogenerated electrons and enhancing the chemisorption of CO2 on the photocatalyst surface.
关键词： Laminar structure,Photocatalytic reduction of CO2,Vanadate,Oxygen vacancy,Photocatalytic activity
更新于2025-09-10 09:29:36
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Role of reactive oxygen species in the visible light photocatalytic mineralization of rhodamine B dye by P25–carbon dot photocatalyst
摘要： An undoped carbon dot (C-dot) with very high photoluminescence quantum yield (PLQY) (25%) and the P25/C-dot composite photocatalyst with improved visible light (VL) photocatalytic activity is reported. The composite exhibits superior VL photodegradation (PD) towards the dyes (RhB) and methyl orange compared to that of control P25. The effect of reactive oxygen species (ROS) is studied in the VL PD of the dye RhB using scavengers. Our study suggests that the ROS responsible for the mineralization of RhB is hydroxyl radical (?OH) and the combination of ?OH and singlet oxygen (1O2) has a synergistic effect on the mineralization of RhB. The ?OH formation is thought to be through the secondary reactions of ROS. Enhancement in the VL PD and the formation of ?OH are attributed to the presence of C-dot. The results suggest that C-dot assists the formation of ?OH through secondary reactions.
关键词： photocatalytic activity,mineralization,reactive oxygen species,visible light,rhodamine B,carbon dot
更新于2025-09-10 09:29:36
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Intrinsic Cu nanoparticle decoration of TiO2 nanotubes: A platform for efficient noble metal free photocatalytic H2 production
摘要： In this work, we grow intrinsically Cu-doped TiO2 nanotubes (TiNTs) by self-organizing anodization of Ti–Cu binary alloys. We demonstrate that up to a copper concentration of 1.5 at.% in the alloy, self-ordered Cu2+-doped nanotubes can be grown. Under UV illumination the Cu2+ ion-doped oxide structures can be converted to nanotubes that carry metallic nanoparticles (NPs) uniformly decorated on top of the TiNTs. We investigate the formation of these metallic nanoparticles under UV illumination by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). The resulting intrinsic copper-doped and decorated TiNTs have a strongly enhanced photocatalytic activity for H2 evolution in comparison to pristine TiNTs. Key is the light-induced conversion of the intrinsic Cu dopant to metallic copper nanoparticles that act as a stable co-catalyst for H2 generation.
关键词： intrinsic copper decoration.,photocatalytic activity,Cu doped TiO2,TiO2
更新于2025-09-10 09:29:36
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Solid-state synthesis and characterization of α-Fe2O3@ZnO nanocomposites with enhanced visible light driven photocatalytic activity
摘要： The α-Fe2O3@ZnOx (x = 25, 50 and 75 mol%) nanocomposites were synthesized by solid-state method. The formation of nanocomposites was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy and UV–Visible absorption spectroscopy. High purity of α-Fe2O3 and ZnO was observed in XRD patterns including lesser amount of ZnFe2O4. The growth of ZnO nanostructures on Fe2O3 rods was affirmed by scanning and transmission electron microscopy. Visible light driven photocatalytic degradation of roxarsone (ROX) was performed by using as-synthesized nanocomposites. The photocatalytic experiments were monitored by high pressure liquid chromatography. The α-Fe2O3@ZnO50% shows 89.7% of ROX degradation efficiency within 330 min and thus it exhibits best photocatalytic activity than the other composites. Moreover, the stability and possible photocatalytic pathway were also evaluated.
关键词： Solid-state synthesis,Nanocomposites,α-Fe2O3@ZnO,Photocatalytic activity,Roxarsone
更新于2025-09-10 09:29:36
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Reference Module in Materials Science and Materials Engineering || Glass, Self-Cleaning
摘要： In this article, the essential technological and the scientific features of self-cleaning glass coatings based on titanium dioxide have been described. In addition, detailed aspects of the coating process and the functional aspects of the coatings, which provide the dual hydrophilic and photoactive cleaning mechanism, have also been presented.
关键词： Titanium Dioxide,Glass,Hydrophilic,Photocatalytic Activity,Self-Cleaning
更新于2025-09-10 09:29:36
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Type II heterojunction in hierarchically porous zinc oxide/graphitic carbon nitride microspheres promoting photocatalytic activity
摘要： Graphitic carbon nitride (g-C3N4) is a visible light active semiconductor. However, low conductivity and high recombination rate of photogenerated electrons and holes limit its application in photocatalysis. In this work, we design and synthesize hierarchically porous zinc oxide/ graphitic carbon nitride (ZnO/g-C3N4) microspheres with type-II heterojunction to effectively degrade rhodamine B (RhB) via increasing the charge-separation efficiency. The ultraviolet-visible (UV-Vis) absorption spectra, Mott-Schottky plots and valence band X-ray photoelectron spectroscope confirm the formation of type-II heterojunction between ZnO nanocrystals and g-C3N4 nanosheets. As a result, the 1.5-ZnO/g-C3N4 composite (the mass ratio of zinc acetate dihydrate to g-C3N4 is 1.5) exhibits the highest photocatalytic activity with good stability and higher photocatalytic degradation rate comparing to pure g-C3N4 and pure ZnO. In addition, our results confirm that ?O2- and h+ are the main active species for ZnO/g-C3N4 in degradation of RhB.
关键词： Active species,Heterojunction,Photocatalytic activity,Hierarchically porous structure,ZnO/g-C3N4
更新于2025-09-10 09:29:36