Photocatalytic Effect Research Articles

The enhanced photocatalytic performance of CPAA doping with different concentrations of Titanium oxide nanocomposite against MB dyes under simulated sunlight irradiations

The pure conjugated polyarylene azomethine (CPAA) and its nanocomposites (CPAA-TiO2) with different concentrations of TiO2 nanoparticles were successfully prepared by in-situ technique and analyzed by different advanced techniques. XRD has confirmed the structural properties and crystallinity of (CPAA) and nanocomposites. The SEM clearly shows that the (CPAA) is uniform and homogeneous, with tightly connected aggregate layers in shape. However, the amount of TiO2 in the nanocomposites greatly affects their morphology, revealing structural differences and indicating a reaction between (CPAA) and TiO2, especially at a higher concentration of 5% TiO2. A new composite of (CPAA) was introduced and the photocatalytic effect for MB was studied. The removal efficiency of (pure-CPAA) over MB dye under simulated sunlight was 62%. However, (CPAA-TiO2 1%) destroyed 90% of MB dyes. It was discovered that the low band gap of (CPAA-TiO2 1% (2.84 eV)) accelerates high electron–hole recombination, increasing photocatalytic activity.

Europium/Graphite Phase Carbon Nitride Composites: Preparation and Photocatalytic Degradation Potential of Different Drugs

AbstractGraphene‐like materials were prepared by thermal copolymerization using melamine as a precursor, and chemical methods successfully synthesized Eu/g‐C3N4 composites containing different europium elements. Degradation rates of 64.3 %, 91.9 %, and 72.8 % were observed in the photocatalytic degradation of Pefloxacin, Enrofloxacin, and Ciprofloxacin under visible light (λ>550 nm). Determine the photocatalytic activity of the composite. When the doping amount was Eu/g‐C3N4‐2 with k=0.0135 min−1, four times greater than that of g‐C3N4, the best photocatalytic effect was obtained. Repeated studies revealed that the Eu/g‐C3N4 composite samples had good cycle stability, and a potential degradation process was postulated.

Enhanced photocatalytic CO2 reduction activity on the novel Z-scheme Co-MOF/Bi2MoO6 to form CO and CH4

Herein, a novel Z-scheme Co-MOF/Bi2MoO6 was synthesized by in-situ growth method. The photocatalytic CO2 reduction effect of Co-MOF/Bi2MoO6 was significantly improved, and the formation rates of CO and CH4 reached 19.76 and 8.24 μmol·g−1·h−1, which corresponded to 1.61 and 2.38 times of Co-MOF (CO: 12.31 μmol·g−1·h−1) and Bi2MoO6 (CH4: 3.46 μmol·g−1·h−1), respectively. The increased photocatalytic activity of Co-MOF/Bi2MoO6 resulted from the enhanced visible light capture capability and the Z-scheme heterojunction formed among Co-MOF and Bi2MoO6, which promoted the efficient separation of photogenerated carriers while retaining the highest redox capacity. The Z-scheme charge transfer direction of Co-MOF/Bi2MoO6 was confirmed by DRS, XPS, ESR, UPS, and the photocatalytic reaction mechanism was explained. In addition, the active substances and intermediates of Co-MOF/Bi2MoO6 in the photocatalytic CO2 reduction process were investigated using ESR and in-situ FT-IR. The work offers a idea for building MOFs-based heterojunctions to improve the effect of photocatalytic CO2 reduction.

Retraction Note: Two co(II)-based coordination polymers: photocatalytic dye degradation properties and treatment effect against colon cancer by inhibiting IL-6-STAT3 inflammatory signaling pathway

Retraction Note: Two co(II)-based coordination polymers: photocatalytic dye degradation properties and treatment effect against colon cancer by inhibiting IL-6-STAT3 inflammatory signaling pathway

Recent Advances in Porous Bio-Polymer Composites for the Remediation of Organic Pollutants.

The increasing awareness of the importance of a clean and sustainable environment, coupled with the rapid growth of both population and technology, has instilled in people a strong inclination to address the issue of wastewater treatment. This global concern has prompted individuals to prioritize the proper management and purification of wastewater. Organic pollutants are very persistent and due to their destructive effects, it is necessary to remove them from wastewater. In the last decade, porous organic polymers (POPs) have garnered interest among researchers due to their effectiveness in removing various types of pollutants. Porous biopolymers seem to be suitable candidates among POPs. Sustainable consumption and environmental protection, as well as reducing the consumption of toxic chemicals, are the advantages of using biopolymers in the preparation of effective composites to remove pollutants. Composites containing porous biopolymers, like other POPs, can remove various pollutants through absorption, membrane filtration, or oxidative and photocatalytic effects. Although composites based on porous biopolymers shown relatively good performance in removing pollutants, their insufficient strength limits their performance. On the other hand, in comparison with other POPs, including covalent organic frameworks, they have weaker performance. Therefore, porous organic biopolymers are generally used in composites with other compounds. Therefore, it seems necessary to research the performance of these composites and investigate the reasons for using composite components. This review exhaustively investigates the recent progress in the use of composites containing porous biopolymers in the removal of organic pollutants in the form of adsorbents, membranes, catalysts, etc. Information regarding the mechanism, composite functionality, and the reasons for using each component in the construction of composites are discussed. The following provides a vision of future opportunities for the preparation of porous composites from biopolymers.

Photo‐Responsive TiO2‐Gold Nanoparticle‐Polymer Nanohybrid Exhibits Photothermal, Thermo‐Release, and Photocatalytic Effects

AbstractThe development of multi‐responsive nanohybrid systems that combine photothermia, thermo‐responsive effects and photocatalysis is a challenging topic in the research of multifunctional materials with a large field of applications. Here, we report the first example of a three‐components light‐responsive nanosystem consisting of titania, gold nanoparticles and poly‐N‐isopropylacrylamide (TiO2‐Au‐PNM). The hybrid nanostructure exhibited photothermal conversion effect upon green‐light excitation and capacity to entrap methylene blue and curcumin selected as cargo models. The formation of the nanohybrid–cargo adducts, the photothermal‐controlled cargo release triggered by green‐light irradiation (532 nm) and mediated by lower critical solution temperature (LCST), as well as the photocatalytic effect prompted by UV‐light excitation (300 nm) were demonstrated by spectroscopic techniques. The mechanism involved in the interaction of the polymeric component with the cargos was investigated by molecular modelling calculations.

Long-lasting, fast-switchable photochromism in Na0.5Bi0.5TiO3 induced by photocatalytic memory effect, and its subsequently enhanced piezoelectric response and catalytic performances

A ferroelectric ceramic material of Na0.5Bi0.5TiO3 was found to possess a pronounced, long-lasting, and fast-switchable photochromic behavior responsive to visible light. The working mechanism of its photochromism could be attributed to an interesting photocatalytic memory effect, during which photogenerated electrons were trapped by Bi3+/Ti4+ and oxygen vacancies generated in Na0.5Bi0.5TiO3. The release kinetics of trapped electrons could be modulated by controlling environment conditions to make its photochromism phenomenon both long-lasting and fast-switchable to meet various application requirements. In the meantime, the photochromism process changed its inner electronic structure, resulting in stronger oxidation capability, increased piezoelectric response, improved charge carrier separation and transfer, and more active oxygen species production. Thus, its photocatalytic, piezocatalytic and photopiezocatalytic performances were all significantly enhanced as demonstrated by its TC-HCl degradation performances. This work offered a novel approach to search for and design inorganic photochromic materials with good reversibility for various technical applications.

Constructing S-scheme Au/g-C3N4/BiVO4 heterojunction with peroxymonosulfate-enhanced photocatalytic activity and mechanism insight

Dissolved organic matter (DOM) in black-odorous water can cause excessive growth of plants and algae, leading to deterioration of water quality. Herein, an S-scheme Au/g-C3N4/BiVO4 heterojunction was constructed using a three-step method for DOM degradation in real black-odorous water in the presence of peroxymonosulfate (PMS). 4Au/g-C3N4/BiVO4/PMS exhibited highly efficient photocatalytic performance, and the DOM removal rate could reach 92.9 %, which was 19.1 and 9.9 times higher than that of g-C3N4/PMS and BiVO4/PMS, respectively. The changes of fluorescence components in DOM were detected using synchronous fluorescence spectra and two-dimensional correlated spectroscopy analysis, and the toxicity of catalytically treated black-odorous water was evaluated by growth inhibition of Escherichia coli. A reasonable S-scheme mechanism was suggested by theoretical calculations and photoelectrochemical tests. The S-scheme mechanism and the synergistic effect of photocatalysis and hybrid advanced oxidation process (HAOP) increased the catalytic activity of Au/g-C3N4/BiVO4/PMS.

Visible light-driven characterisation of AgI/CeO2/rGO nanocomposites and their application in levofloxacin degradation

AgI/CeO2/rGO complexes were prepared in different proportions and characterized by XRD, SEM, TEM, FT-IR, XPS, BET, PL, I-T and EIS. The photocatalytic degradation experiments of levofloxacin (LVF) under visible light (λmax=245 nm) was performed to determined the photocatalytic activity of the composites. When the concentration of simulated pollutants is 20 mg/L and the amount of application is 15 mg, the doping ratio is AgI/CeO2/3%-rGO, and the photocatalytic effect of the nanocomposite with pH 5 is the best. The maximum photocatalytic degradation rate of 98.02% can be achieved. The cyclic stability of the composites and the kinetics were also analyzed, and possible degradation mechanisms were also proposed. The intermediates were also detected using high performance liquid chromatography-mass spectrometry(HPLC-MS) to obtain the possible degradation process. The results show that AgI/CeO2/rGO composite exhibits good photocatalytic degradation performance under visible light, and the maximum photocatalytic degradation rate for treating pollutants containing LVF is 98.02%. These findings are expected to provide important theoretical and practical guidance for environmental treatment and research and development of photocatalytic materials.

Antibacterial and photocatalytic effects of newly synthesized zinc oxide nanoparticles derived from Mongolian honey

Development of bio-compatible, bio-safe and environmentally friendly nanoparticles is a matter of urgency for research in the field of nanotechnology. In this study, we aimed to prepare zinc oxide nanoparticles from Mongolian honey as raw material and to determine its biological activities. Honey-based zinc oxide nanoparticles were obtained by green synthesis method, and their characteristics and biological activities were evaluated. Developed zinc oxide nanoparticles from Khentii honey and Selenge honey were at a size of 16.02 nm and 95.23 nm, respectively. A characteristic band of Khentii honey-based zinc oxide nanoparticles was observed at 466 cm–1 and a band of Selenge honey-based zinc oxide nanoparticles was also observed at 434 cm–1. Antibacterial and photocatalytic effects were detected for the developed nanoparticles. The study suggested that newly synthesized honey-based zinc oxide nanoparticles might be an effective tool against bacterial infection.

A self-standing dual-electric field synergistic Janus nanofibre piezoelectric photocatalyst with degradation of antibiotics: Performances, DFT calculation and mechanism unveiling

A self-standing dual-electric field synergistic [TiO2/polyvinylidene fluoride (PVDF)]//[g-C3N4 tube/PVDF] Janus nanofibres (named as [TP]//[CTP]JNs) S-scheme heterostructure piezoelectric photocatalyst is designed and constructed via conjugative electrospinning. Dual-fields of built-in electric fields supplied by S-scheme heterostructure and piezoelectric field formed by PVDF jointly boost separation and transfer of photo-induced charges. As a case study, piezoelectric photocatalytic efficiency of [TP]//[CTP]JNs for tetracycline hydrochloride (TCH) under ultrasonic united with simulated sunlight illumination is 93.35% (40 min), which is 1.39 times of the photocatalytic efficiency (light illumination only) and 5.32 times of piezoelectric catalytic efficiency (applying ultrasonic only), proving the advantages of the synergistic effect of piezoelectric catalysis and photocatalysis on contaminant degradation. The dynamic behaviors of photocatalysis and photo-generated charges are deeply revealed through fs-TA and TRPL decay spectra, and the degradation pathways of antibiotics are reasonably speculated by combining LCMS spectra with Fukui index. By the degradation ability, COMSOL simulation and DFT calculation, the structural advantage of Janus nanofibers is fully verified, and S-scheme charge transfer mechanism is confirmed by combining a series of sound ample experiments with theoretical calculations. Additionally, the construction mechanism of Janus nanofibers is proposed, and corresponding construction technique is established.

CdS@CS/PVA inverse opal films as photocatalyst

We prepared CdS@CS/PVA inverse opal (IO) films by the colloidal photonic crystal (CPC) template method. The photonic structure of the CdS@CS/PVA IO films consists of three-dimensional periodic macropores interconnected by CS/PVA polymers. The as-prepared CdS@CS/PVA IO films were utilized as photocatalysts for the degradation of methylene blue dyes. The degradation rate of methylene blue by the CdS@CS/PVA IO film catalyst was 92%, while that of the CdS@CS/PVA film catalyst was 55% for 6 h. The photocatalytic degradation effect of the CdS@CS/PVA IO film catalyst on methylene blue is [Formula: see text]1.7 times higher than that of the CdS@CS/PVA film catalyst, which proves that the introduction of the inverse opal structure into the photocatalyst is beneficial to improve the efficiency of the photocatalyst for degrading dyes.

EM and CT synergistic SERS enhancement in Si/TiO2/Ag heterostructures via local interfacial effect

The Si/TiO2/Ag heterostructures with high SERS sensitivity were prepared by sol–gel and electrochemical self-assembly. The electromagnetic (EM) and charge transferring (CT) synergistic mechanism for SERS enhancement was explored by FDTD. The “localized interfacial effect (LIE)” of metal–semiconductor heterostructures can result in the CT between them and the charge carriers’ redistribution, which can facilitate the probe molecules’ adsorption and generate the 3D volume-enhancement of electromagnetic fields, therefore improve the SERS performance effectively. Furthermore, the morphology of Ag was flexibly regulated by changing the applied voltage, and the optimal SERS performance was achieved. With the R6G as a probe molecule, the ultra-low concentration of 10-13 M can be detected. The EF is estimated to be about 1.75 × 1011, and the RSD is about 4.3 %. The photocatalytic effect of Si/TiO2/Ag heterostructure can realize the SERS substrates’ UV self-cleaning and recyclable use with high stability.

Regulating Sulfur Redox Kinetics by Coupling Photocatalysis for High-Performance Photo-Assisted Lithium-Sulfur Batteries.

Challenges such as shuttle effect have hindered the commercialization of lithium-sulfur batteries (LSBs), despite their potential as high-energy-density storage devices. To address these issues, we explore the integration of solar energy into LSBs, creating a photo-assisted lithium-sulfur battery (PA-LSB). The PA-LSB provides a novel and sustainable solution by coupling the photocatalytic effect to accelerate sulfur redox reactions. Herein, a perovskite quantum dot-loaded MOF material serves as a cathode for the PA-LSB, creating built-in electric fields at the micro-interface to extend the lifetime of photo-generated charge carriers. The band structure of the composite material aligns well with the electrochemical reaction potential of lithium-sulfur, enabling precise regulation of polysulfides in the cathode of the PA-LSB system. This is attributed to the selective catalysis of the liquid-solid reaction stage in the lithium-sulfur electrochemical process by photocatalysis. These contribute to the outstanding performance of PA-LSBs, particularly demonstrating a remarkably high reversible capacity of 679 mAh g-1 at 5 C, maintaining stable cycling for 1500 cycles with the capacity decay rate of 0.022 % per cycle. Additionally, the photo-charging capability of the PA-LSB holds the potential to compensate for non-electric energy losses during the energy storage process, contributing to the development of lossless energy storage devices.

Photocatalytic degradation of acid violet dye by sunlight exposure using green synthesized magnesium oxide nanoparticles

An aqueous extract of Phyllanthus Emblica fruit extract was used as a precursor in the effective synthesis of Magnesium Oxide Nanoparticles (MgONP) and the same was calcined at different temperatures. The thermal study demonstrated that MgO nanoparticles evolved from Mg(OH)2 by the identification of characteristic weight loss curves and endothermic peaks in TGA and DTA, respectively. UV-visible analysis showed that the peak shifts to a longer wavelength at 350 nm when the calcination temperature rises from 200 to 600 °C, indicating a decrease in the size of MgONP particles. On the other hand, Tauc plot analysis showed that the band gaps between the precursor and calcined MgO samples varied from 5.84 to 3.70 eV. FTIR and XRD analysis confirmed the synthesis of MgONPs from Mg(OH)2 exhibiting spherical shapes of around 20 nm in size.Twenty minutes of exposure to sunshine caused the dye's colour to entirely vanish, demonstrating the remarkable photocatalytic effectiveness of MgONP calcined at 600 °C. The effective breakdown of Acid Violet was confirmed by the rate constant of the photocatalytic behaviour increasing proportionately with the catalyst dose. Furthermore, it was suggested by the Langmuir and Freundlich isotherm models that Acid Violet efficiently adheres to the photocatalyst surface when R2 values are nearer to 1. There are several potential applications for MgO nano adsorbents in dye removal processes, as evidenced by desorption studies that showed their reusability.

Regulating Sulfur Redox Kinetics by Coupling Photocatalysis for High‐Performance Photo‐Assisted Lithium‐Sulfur Batteries

AbstractChallenges such as shuttle effect have hindered the commercialization of lithium‐sulfur batteries (LSBs), despite their potential as high‐energy‐density storage devices. To address these issues, we explore the integration of solar energy into LSBs, creating a photo‐assisted lithium‐sulfur battery (PA‐LSB). The PA‐LSB provides a novel and sustainable solution by coupling the photocatalytic effect to accelerate sulfur redox reactions. Herein, a perovskite quantum dot‐loaded MOF material serves as a cathode for the PA‐LSB, creating built‐in electric fields at the micro‐interface to extend the lifetime of photo‐generated charge carriers. The band structure of the composite material aligns well with the electrochemical reaction potential of lithium‐sulfur, enabling precise regulation of polysulfides in the cathode of the PA‐LSB system. This is attributed to the selective catalysis of the liquid‐solid reaction stage in the lithium‐sulfur electrochemical process by photocatalysis. These contribute to the outstanding performance of PA‐LSBs, particularly demonstrating a remarkably high reversible capacity of 679 mAh g−1 at 5 C, maintaining stable cycling for 1500 cycles with the capacity decay rate of 0.022 % per cycle. Additionally, the photo‐charging capability of the PA‐LSB holds the potential to compensate for non‐electric energy losses during the energy storage process, contributing to the development of lossless energy storage devices.

Photocatalytic Degradation of Quinolones by Magnetic MOFs Materials and Mechanism Study.

With the rising incidence of various diseases in China and the constant development of the pharmaceutical industry, there is a growing demand for floxacin-type antibiotics. Due to the large-scale production and high cost of waste treatment, the parent drug and its metabolites constantly enter the water environment through domestic sewage, production wastewater, and other pathways. In recent years, the pollution of the aquatic environment by floxacin has become increasingly serious, making the technology to degrade floxacin in the aquatic environment a research hotspot in the field of environmental science. Metal-organic frameworks (MOFs), as a new type of porous material, have attracted much attention in recent years. In this paper, four photocatalytic materials, MIL-53(Fe), NH2-MIL-53(Fe), MIL-100(Fe), and g-C3N4, were synthesised and applied to the study of the removal of ofloxacin and enrofloxacin. Among them, the MIL-100(Fe) material exhibited the best photocatalytic effect. The degradation efficiency of ofloxacin reached 95.1% after 3 h under visible light, while enrofloxacin was basically completely degraded. The effects of different materials on the visible photocatalytic degradation of the floxacin were investigated. Furthermore, the photocatalytic mechanism of enrofloxacin and ofloxacin was revealed by the use of three trappers (▪O2-, h+, and ▪OH), demonstrating that the role of ▪O2- promoted the degradation effect of the materials under photocatalysis.

Electrochemically produced nano-TiO2-coated SiC membranes for photocatalytic water treatment: Preparation, characterization, and hydroxyl radical formation.

Photocatalytically active ceramic flat sheet membranes based on a nanostructured titanium dioxide (TiO2) coating were produced for photocatalytic water treatment. The nano-TiO2 layer was produced by a novel combination of magnetron sputtering of a thin titanium layer on silicon carbide (SiC) membranes, followed by electrochemical oxidation (anodization) and subsequent heat treatment (HT). Characterization by Raman spectra and field emission scanning electron microscopy proved the presence of a nanostructured anatase layer on the membranes. The influence of the titanium layer thickness on the TiO2 formation process and the photocatalytic properties were investigated using anodization curves, by using cyclovoltammetry measurements, and by quantifying the generated hydroxyl radicals (OH•) under UV-A irradiation in water. Promising photocatalytic activity and permeability of the nano-TiO2-coated membranes could be demonstrated. A titanium layer of at least 2 μm was necessary for significant photocatalytic effects. The membrane sample with a 10 μm Ti/TiO2 layer had the highest photocatalytic activity showing a formation rate of 1.26 × 10-6 mmol OH• s-1. Furthermore, the membranes were tested several times, and a decrease in radical formation was observed. Assuming that these can be attributed to adsorption processes of the reactants, initial experiments were carried out to reactivate the photocatalyzer.

Bi-ZFO/BMO-Vo Z-scheme heterojunction photocatalysis-PMS bidirectionally enhanced coupling system for environmental remediation

Given the urgency of organic pollutant removal and the low efficiency of advanced oxidation processes (AOPs), a novel Bi-ZFO/BMO-Vo photocatalyst was fabricated via the solvothermal method. A coupling system was constructed to combine photocatalysis with peroxymonosulfate (PMS) oxidation processes, which synergistically degrade organic pollutants. Bi-ZFO/BMO-Vo exhibited excellent photocatalytic performance, which could remove 100 % RhB in 110 min and degrade 100 % MG in 70 min, and 88 % H-TC in 50 min. The excellent catalytic performance of Bi-ZFO/BMO-Vo was not only attributed to the synergistic effect of PMS activation and photocatalysis, but also attributed to the SPR effect of Bi nanoparticles, electron capture of oxygen vacancies, and intense contact of Bi-ZFO/BMO-Vo heterojunctions. The active species capture experiments and EPR tests indicated that 1O2, SO4–·, ·OH, and O2–· worked together for the RhB removal. The degradation intermediates of RhB were identified by LC-MS. Based on the experimental results, the band structure and Z-scheme charge transfer mechanism were proposed. Toxicity evaluation indicated that Bi-ZFO/BMO-Vo-Vis/PMS could significantly reduce RhB toxicity. This efficient and stable catalyst is expected to be used in organic wastewater degradation and practical applications.

The Synthesis of Ag/TiO2 via the DC Magnetron Sputtering Method and Its Application in the Photocatalytic Degradation of Methyl Orange in Na2SO4 Solution

TiO2 and TiO2 films modified with Ag (Ag/TiO2) were prepared via the DC magnetron sputtering method and the degree of modification was controlled via the sputtering power and time of Ag. The microstructures and properties of these films were characterized using field emission scanning electron microscopy, X-ray diffractometry, ultraviolet–visible diffuse reflectance spectrometry, atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). The results show that the prepared films have an anatase structure. Compared with pure TiO2, Ag deposition can improve the utilization of light. The three-dimensional images of Ag/TiO2 clearly show that with the increase in Ag sputtering power and sputtering time, Ag particles on the surface of the film gradually increase, and the structure of the film is relatively dense. The photocatalytic effect of Ag/TiO2 films is the best when the Ag sputtering power is 5 W and the sputtering time is 50 s. Under high-pressure mercury lamp irradiation, the photocatalytic degradation rate of methyl orange (MO) in pure MO solution with Ag/TiO2-5 W-50 s can reach 100% within 55 min, whereas that in MO-Na2SO4 mixed solution can reach 99.55% within 65 min. The results suggest that the presence of Na2SO4 in MO solution can inhibit the degradation of MO using Ag/TiO2, the result of XPS suggests that Na2SO4 accelerates the oxidation of Ag, which may lead to an increase in the recombination rate of photogenerated electron–hole pairs and a decrease in the degradation rate. During the process of recycling photocatalysts, the degradation rate of MO was apparently reduced. A possible reason is that the Ag particles have been oxidized and products of photocatalytic degradation are on the surface of the photocatalyst. The photocatalytic degradation mechanism was studied.