Visible Photocatalytic Degradation Research Articles

Unveiling the Synthesis of a Zirconium-Substituted Copper Bismuth Oxide Catalyst for Visible Light-Responsive Photocatalytic Degradation of Persistent Organic Dye

Unveiling the Synthesis of a Zirconium-Substituted Copper Bismuth Oxide Catalyst for Visible Light-Responsive Photocatalytic Degradation of Persistent Organic Dye

Visible light-induced photocatalytic degradation of anticancer drugs via zeolitic imidazole framework (ZIF-8@ZIF-67): mechanistic insights

Visible light-induced photocatalytic degradation of anticancer drugs via zeolitic imidazole framework (ZIF-8@ZIF-67): mechanistic insights

Investigation of the Structural, Phase Formation, Optical, Bias-Dependent Dielectric and Visible Region Photocatalytic Degradation Performance of Zn1−xFexO Nanoparticles Prepared Using the Sol–Gel Method

Investigation of the Structural, Phase Formation, Optical, Bias-Dependent Dielectric and Visible Region Photocatalytic Degradation Performance of Zn1−xFexO Nanoparticles Prepared Using the Sol–Gel Method

Fabrication of ZnO[sbnd]Cu3SnS4 NCs for enhanced visible light-induced photocatalytic degradation of carvedilol

The widespread use of pharmaceutical drugs like carvedilol (CAR) has raised concerns regarding antibiotic resistance, environmental pollution, and potential human health risks. This study addresses these issues by employing advanced pristine nanomaterials, including ZnO and Cu3SnS4 to intricately engineer ZnOCu3SnS4 nanocomposite (NCs). These NCs are designed for enhanced photocatalytic degradation of CAR. Detailed characterization through SEM, and elemental mapping reveals the nanocluster morphology, amorphous nature, proper deposition distribution, and heterojunction formation. XRD studies confirm the purity of the synthesized materials, while XPS validate their chemical states and bonding nature. BET and BHJ analyses demonstrate the enhanced surface area and mesoporous nature of the NCs respectively. UV–visible DRS illustrates successful visible-light sensitization of the ZnOCu3SnS4 NCs with a bandgap of 2.96 eV. Photoluminescence studies indicate reduced charge carrier recombination in the NCs. .OH being the dominant radical involved in photodegradation. The photocatalytic degradation of CAR by ZnOCu3SnS4 NCs achieves a remarkable degradation efficiency of 98 % under optimal condition. These NCs also show outstanding stability across several cycles and remain to function in the presence of ions. Finally, GC–MS analysis suggests the potential CAR degradation routes that result in less hazardous end products. In conclusion, the present research highlights the potential of ZnOCu3SnS4 NCs for efficient wastewater treatment and highlights their capacity to tackle issues related to pharmaceutical drug contamination.

Visible light-induced photocatalytic degradation of tetrabromobisphenol A on platinized tungsten oxide

In this study, we investigated the degradation of the flame retardant tetrabromobisphenol A (TBBPA) using platinized tungsten oxide (Pt/WO3), synthesized via a simple photodeposition method, under visible light. The results of degradation experiments show a significant enhancement in TBBPA degradation upon surface platinization of WO3, with the degradation rate increasing by 13.4 times compared to bare WO3. The presence of Pt on the WO3 surface stores conduction band electrons, which facilitates the two-electron reduction of oxygen and enhances the production of valence band holes (hVB+) and hydroxyl radicals (●OH). Both hVB+ and ●OH are significantly involved in the degradation of TBBPA in the visible light-irradiated Pt/WO3 system. This was verified through fluorescence spectroscopy employing coumarin as a chemical probe and oxidizing species-quenching experiments. The analysis of degradation products and their toxicity assessment demonstrate that the toxicity of TBBPA-contaminated water is significantly reduced after Pt/WO3 photocatalysis. The degradation rate of TBBPA increased with increasing Pt/WO3 dosage, reached an optimum at a Pt content of 0.5 wt%, but decreased with increasing TBBPA concentration. The decrease in degradation efficiency of Pt/WO3 was minor, both in the presence of various anions and after repeated use. This study proposes that Pt/WO3 is a viable photocatalyst for the degradation of TBBPA in water under visible light.

Enhanced photocatalytic activities of FCNO nanoparticles on graphitic carbon nitride

Efficient charge separation and broadened light absorption are of crucial importance for photocatalytic environmental remediation, and graphitic carbon nitride (g-C3N4) is a very promising photocatalyst for this purpose. Herein, the synthesis of FCNO nanoparticles embedded within graphitic carbon nitride (g-C3N4) by hydrothermal route assisted with pyrolysis of urea was presented. The g-C3N4 was obtained from an abundantly available precursor urea and the synthesis process played double role. Urea reacted with metal salts to convert them into metallic oxides and yielded g-C3N4. The experimental results revealed the in-situ fabrication of FCNO nanoparticles and formation of g-C3N4. The band gap narrowing made it possible that the samples were able to show a wide range of visible light absorption which made them suitable for photocatalytic activity studies. Thus, the materials were utilized for the visible light-based photocatalytic degradation of methylene blue dye. Photocatalytic degradation efficiency with ~93 % was achieved by the composite FCNO/g-C3N4 (50:50). The present approach for the synthesis of materials was proved to be cost-effective and time saving which enabled their use as recyclable photocatalyst.

Bismuth-rich BiOBr/Bi24O31Br10/Ti3C2 polyheterojunction for visible photocatalytic degradation of dyes and Cr(VI) reduction and hydrogen production applications

The construction of bismuth-rich heterostructures is an important strategy to improve the performance of bismuth-based visible photocatalytic materials. In this study, the binary heterojunction BiOBr/Bi24O31Br10 (BOB) with efficient visible photocatalytic activity was constructed by in situ induced growth of BixOyBrz on the surface of BiOBr, and the multivariate heterojunction composite BiOBr/Bi24O31Br10/Ti3C2 (BOBT) was synthesized by using Ti3C2 as an electron acceptor. It was shown that the solvothermal pH, Bi/Br and calcination temperature had a strong influence on the composition and crystalline structure of BOBT. The optimized synthesis conditions were pH=8, Bi/Br=1/1 (molar ratio), and calcination temperature of 400℃. The introduction of Mxene significantly enhanced the visible-light responsiveness and photoelectric efficiency of BOBT. The visible light-catalyzed degradation of complex conjugated systems containing aromatic and azo structures by BOBT was synchronously accompanied by benzene ring opening, demonstrating an efficient visible light degradation capability. BOBT has a reduced reduction current peak compared to BOB, can rapidly reduce Cr (VI), and improves the photocatalytic hydrogen production efficiency by nearly three times compared to BiOBr without the addition of Pt additives. This study provides fundamental data for the construction of efficient bismuth-based visible photocatalytic materials and their applications.

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.

Retraction Note: Visible light-enhanced photocatalytic dye degradation and hydrogen evolution performance of BiVO4 thin films prepared at various annealing temperatures

Retraction Note: Visible light-enhanced photocatalytic dye degradation and hydrogen evolution performance of BiVO4 thin films prepared at various annealing temperatures

Visible light-induced photocatalytic degradation of methylene blue dye using pure phase bismuth ferrite nanoparticles

The degradation of organic dyes in wastewater has become a significant environmental issue, requiring the development of degradation technologies that are both effective and environmentally friendly. The present study employed the sol-gel approach to synthesize nanoparticles of phase pure bismuth ferrite (BiFeO3). The nanoparticles were assessed for their ability to efficiently degrade methylene blue (MB) dye, especially under visible light irradiation. The X-ray diffractogram (XRD) confirmed the formation of BiFeO3 nanoparticles, with an average crystallite size of 48 nm. The material's band gap, with a value of 1.84 eV, demonstrates its capacity to effectively absorb light, including wavelengths within the visible spectrum. Scanning electron microscopy (SEM) was used to identify porous aggregated particles. Both Raman and Fourier transform infrared spectroscopy (FTIR) confirm the successful synthesis of pure BiFeO3 in the desired phase. The BiFeO3 photocatalyst exhibited a significant surface area and isotherms of type IV, a characteristic typically observed in mesoporous materials, as determined by the Brunauer-Emmett-Teller (BET) analysis. The efficacy of BiFeO3 nanoparticles in facilitating the decomposition of MB in a water-based solution was evaluated by visible light photocatalysis. An efficiency degradation of 98.49 % was recorded for MB within 2 h.

Visible Light-Induced Photocatalytic Degradation of Methylene Blue Using Copper-Doped Carbon Dots One-Step Derived from CCA-Wood

Developing novel eco-friendly broad-spectrum visible light photocatalysts for dye removal is one of the urgent problems for water treatment. Here, copper-doped carbon dots (CDs) were reported to be directly fabricated from chromated copper arsenate (CCA) wood waste for the photocatalytic degradation of the methylene blue dye. The properties of the resulting CDs were thoroughly characterized and analyzed, preceding an investigation into the adsorption kinetics of dye degradation. The kinetic study showed that reactant concentration was the rate-limiting factor. The obtained CDs showed a 151 mg/g photocatalytic degradation capacity. Comparing pure CDs to CDs/TiO2 composites, the former demonstrated higher photodegradation efficiency. This superiority can be attributed to the synergistic action of adsorption and photocatalytic degradation working in tandem. This study prepared Cu doped CDs and elucidated the photocatalysis mechanism of methylene blue degradation by CDs. The photodegradation of organic dyes through CDs derived from waste CCA wood emerges as an eco-friendly, facile, and highly efficient method.

Enhanced visible light photocatalytic degradation of dyes by the oxygen-rich vacancy-assisted S-scheme heterojunction Al2O3/BiOBr: Catalytic mechanism and performance evaluation

A heterojunction Al2O3/BiOBr composite photocatalyst, characterized by an S-scheme structure and enriched with oxygen vacancies, was synthesized through a solvothermal reaction coupled with an in situ growth approach. Oxygen vacancies on the catalyst surface, enhanced by the robust coupling between Al2O3 and BiOBr, were corroborated by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Techniques such as UV–vis diffuse reflectance spectroscopy (DRS), UV photoelectron spectroscopy (UPS), Mott–Schottky characterization, and experimental radical trapping experiments collectively validated the pathways for migrating photogenerated carriers. The interplay between the surface oxygen vacancies and the S-scheme Al2O3/BiOBr heterojunction, which possesses potent redox capabilities, significantly improved the photocatalytic degradation. This enhancement was particularly evident in the outstanding visible photocatalytic degradation performance against rhodamine B (RhB), methyl orange (MO), and basic fuchsin (BF). The synthesized composite photocatalysts demonstrated 92% retention of degradation efficiency after five recycling cycles, indicating their considerable stability.

Addition of silver nanoparticles to the zinc ferrite/polyaniline composition for boosting its visible photocatalytic degradation.

Enhancing the photocatalytic activity of ZnFe2O4 with a good energy band gap to degrade industrial waste under sunlight illumination can help to develop green environments. Here, to improve the photocatalytic efficiency of ZnFe2O4 ferrites, they were merged with polyaniline (PAni) and silver (Ag) nanoparticles to synthesize Ag@ZnFe2O4-PAni plasmonic nanostructures. The as-synthesized nanostructures were characterized using a series of advanced characterization techniques to confirm successful formation and investigate photocatalytic improvement origins. It was found that incorporating Ag NPs along with the PAni to ZnFe2O4 increases its absorption power and red-shifts its energy band gap, which increases the electron-hole production rate by exposure to light in ZnFe2O4. Contribution of the surface plasmon resonance effect of Ag NPs and conjugated double bonds of PAni to charge transfer mechanisms in Ag@ZnFe2O4-PAni material increased charge separation during photocatalytic process, boosting the photodegradation performance of ZnFe2O4.

High entropy spinel oxide nanoparticles for visible light-assisted photocatalytic degradation of binary mixture of antibiotic pollutants in different water matrixes

The photocatalytic application of magnetic high entropy oxide nanoparticles in water and wastewater treatment processes is exemplified for the first time, purely from a practical perspective.

Nano-island-like heterojunction of nitrogen-doped carbon quantum dots anchoring on titanium oxide nano sheets@Cu2O for enhancing visible light-driving photocatalytic degradation of methyl orange

Cu2O and TiO2 are promising for photocatalysis owing to their lower cost and excellent performance. Unfortunately, the efficiency of light utilization by Cu2O and TiO2 is still low. Herein, the nano-island-like heterojunction of nitrogen-doped carbon quantum dots anchoring on titanium oxide nano sheets@Cu2O (NCQDs/TNSs@Cu2O) was synthesized through the hydrothermal and chemical precipitation process and its photocatalytic performance was systematically characterized. Benefiting from the unique heterojunction, NCQDs/TNSs@Cu2O exhibited a superior photocatalytic performance. High-resolution transmission electron microscopy showed that NCQDs/TNSs nanoclusters were decorated on Cu2O nanoparticle surface and formed heterojunctions. The UV–Vis-DRS spectra indicated that NCQDs/TNSs@Cu2O exhibited the strong adsorption peaks between 400 and 650 nm. Under simulated sunlight irradiation, NCQDs/TNSs@Cu2O exhibited excellent photocatalytic degradation performance on methyl orange. For example, the degradation was completed within 20 min and the photo-degradation capacity of NCQDs/TNSs@Cu2O remained 90.1 % after four recycling cycles. Furthermore, the potential mechanism for the photo-induced degradation was proposed based on the active substances identified through the electron spin resonance. Conclusively, this study provides a novel perspective on the role of NCQDs and prepares the way for the design of the biomass-based photocatalyst.

Compact wirelessly-powered photocatalyst-coated spheres: Concept development and application for oxidative wastewater treatment and membrane fouling control

Wirelessly powered photocatalyst-coated spheres (WPS) were successfully developed and wirelessly powered from outside the reactor using resonant inductive coupling. Diverse applications of WPS were demonstrated for the visible light-assisted photocatalytic degradation of methylene blue (textile dye), diclofenac, and triclosan (pharmaceutical compounds) and fouling control of ceramic membranes. These catalyst-coated WPS successfully generated O2− as the main reactive oxygen species (ROS). As demonstrated, these WPS are low-cost, easy to fabricate, have excellent visible light sources, and can be used as the photocatalyst carrier. The acrylic shell of WPS is transparent to light with wavelengths from 300 to 800 nm. Increasing the number of WPS can increase the light intensity proportionally, and 8 WPS can be powered by one power coil outside the reactor. A higher quantity of WPS per reaction volume can be used to improve the reactivity, bringing the use of WPS reactors closer to industrial applications. This is the first report on the use of WPS in the ceramic membrane reactor for fouling control, a 50 % delay compared to control, and highlights the versatility of this system. This work would open up new exploration avenues for membrane fouling control using WPS-based heterogeneous photocatalysis.

Optimization of metal dopant effect on ZnO nanoparticles for enhanced visible LED photocatalytic degradation of citalopram: comparative study and application to pharmaceutical cleaning validation

AbstractMetal doping is an effective method to tune the optical and chemical properties of nanoparticles. Herein, a comparative study was conducted to assess the effect of metal dopant (Mg, Cu and Sn) on ZnO nanoparticles for visible LED photocatalysis. The photocatalysts were synthesized via a facile co-precipitation method. Doped ZnO nanoparticles were employed for photodegradation of citalopram; a commonly used antidepressant drug. The structural, morphological and optical properties of the nanoparticles were analyzed using high resolution transmission electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller measurements and diffuse reflectance spectroscopy. A decrease in band gap energy was obtained for Mg (3.21 eV), Cu (3.15 eV) and Sn (3.05 eV) compared to undoped ZnO (3.34 eV). Results showed that the photocatalytic activity of ZnO nanoparticles towards citalopram degradation under visible light was enhanced by doping with Sn which showed superior photocatalytic performance compared to Cu. Whereas, Mg doped ZnO demonstrated the lowest photocatalytic activity. Full factorial design (24) was conducted to investigate the effect of dopant, pH, catalyst loading and initial citalopram concentration on the efficiency of the treatment process. The interaction between the metal dopant and pH had significant impact on photodegradation efficiency. At optimum conditions, 80% degradation of 25 µg mL−1 citalopram was obtained in 2 h using commercially available LED light using 0.5 mg mL−1 Sn doped ZnO. Kinetics of citalopram degradation was also investigated and was found to follow pseudo-first order kinetics. The optimized photocatalytic protocol was successfully applied for treatment of water samples obtained from production lines during the cleaning validation cycles of citalopram. Sn and Cu doped ZnO nanoparticles had great sustainability for wastewater treatment as it kept its catalytic behavior up to three cycles without significant decrease in photocatalytic activity. The integration of such an approach into the currently employed cleaning validation protocols would offer an economical advantage for pharmaceutical wastewater treatment. Graphical Abstract

Photocatalytic degradation performance of antibiotics by WO3/α-Fe2O3/zeolite type II heterojunction with core-shell structure.

The accumulation of antibiotics in the environment can be harmful to human health, and research on their disposal technologies is of increasing interest. In this study, WO3/α-Fe2O3/zeolite (WFZ) type II heterojunction composites with core-shell structures were prepared by coupling WO3 semiconductors with visible-light photocatalytic activity with α-Fe2O3 via hydrothermal synthesis using zeolite as a carrier for the adsorption of synergistic photocatalytic degradation of antibiotics in wastewater. X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), specific surface, and porosity measurements were used to characterize the structure of WFZ type II heterojunction. The performance of WFZ heterojunction for the visible photocatalytic degradation of antibiotics (tetracycline hydrochloride (TCH), ciprofloxacin (CIP), and levofloxacin hydrochloride (LVF)) was investigated. Through four photocatalytic cycles, the catalyst exhibited excellent durability and stability. This was attributed to the core-shell structure and type II heterojunction promoting the effective separation of photogenerated carriers and the extended visible light response range, which resulted in the best photocatalytic activity of the catalyst under visible light irradiation. Radical trapping experiments showed that superoxide radicals (•O2-) and hydroxyl radical (•OH) were the main active species that played a major role in the photocatalytic degradation. These findings show that the synthesized WFZ type-II heterojunction can be used as a reliable visible-light-responsive photocatalyst for the treatment of antibiotics in wastewater.

Preparation of 3D BiOI microspheres for highly efficient visible light-induced photocatalytic degradation of tetracycline

Semiconductor photocatalysts for pharmaceutical antibiotic wastewater treatment are subject to increasing attention. Herein, BiOI photocatalysts were prepared by a one-step solvothermal method using ethylene glycol (EG) as solvent and their tetracycline (TC) degradation activities under visible light irradiation were compared. Catalyst preparation temperature, time, and pH conditions were optimized, and the catalyst physicochemical properties were characterized. Solution pH was found to have a significant effect on the morphology, electronic structure, and surface exposed facet of BiOI. Catalysts synthesized in the absence of NaOH presented more regular 3D flower-like microspheres, possessed larger surface area, were composed of many small nanosheets predominantly exposing the (001) facet, and showed better photogenerated electron-hole pairs separation efficiency. The optimized BiOI presents superior TC degradation efficiency (73.6%) under visible light irradiation, and recycling experiments indicated that the catalysts have good stability and reusability. The active species were investigated by free radical trapping experiments, revealing that •O2− plays a major role in the photodegradation process. Possible TC degradation pathways are proposed according to mass spectrometry analysis.

Tungsten-based nanocatalysts with different structures for visible light responsive photocatalytic degradation of bisphenol A

Environmental pollution, such as water contamination, is a critical issue that must be absolutely addressed. Here, three different morphologies of tungsten-based photocatalysts (WO3 nanorods, WO3/WS2 nanobricks, WO3/WS2 nanorods) are made using a simple hydrothermal method by changing the solvents (H2O, DMF, aqueous HCl solution). The as-prepared nanocatalysts have excellent thermal stability, large porosity, and high hydrophilicity. The results show all materials have good photocatalytic activity in aqueous media, with WO3/WS2 nanorods (NRs) having the best activity in the photodegradation of bisphenol A (BPA) under visible-light irradiation. This may originate from increased migration of charge carriers and effective prevention of electron‒hole recombination in WO3/WS2 NRs, whereby this photocatalyst is able to generate more reactive •OH and •O2– species, leading to greater photocatalytic activity. About 99.6% of BPA is photodegraded within 60 min when using 1.5 g/L WO3/WS2 NRs and 5.0 mg/L BPA at pH 7.0. Additionally, the optimal conditions (pH, catalyst dosage, initial BPA concentration) for WO3/WS2 NRs are also elaborately investigated. These rod-like heterostructures are expressed as potential catalysts with excellent photostability, efficient reusability, and highly active effectivity in different types of water. In particular, the removal efficiency of BPA by WO3/WS2 NRs reduces by only 1.5% after five recycling runs and even reaches 89.1% in contaminated lake water. This study provides promising insights for the nearly complete removal of BPA from wastewater or different water resources, which is advantageous to various applications in environmental remediation.