Photodegradation Of Organic Pollutants Research Articles

Hydrothermally synthesized Hierarchical Pom-Pom-like Gadolinium Modified Tungsten Oxide reinforced with rGO for annihilation of Acetylsalicylic Acid and Crystal Violet

Herein, novel hierarchical Gd@WO3 pom-pom-like microstructures have been prepared through the hydrothermal method and combined with RGO sheets (denoted as RGO/Gd@WO3). The synthesized materials, along with their analogs, were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), Mott-Schottky, current-voltage (I-V), electrochemical impedance spectroscopy (EIS), and optical analyses. The unique morphology of pom-pom-like microstructures allowed better interaction with pollutant molecules. Rare earth element (Gd3+) ions act as trapping species for photo-generated electrons and prolong the life span of reactive oxygen species (ROS). The high conductivity and flexible nature of RGO sheets provided fast transport of active species and provided stability to the photocatalytic material. To test the photocatalytic efficiency of RGO/Gd@WO3, crystal violet (CV) and acetylsalicylic acid (ASA) were used as model pollutants. Under a mimetic light source, RGO/Gd@WO3 exhibited maximum photodegradation of 98.8% and 84% for CV and ASA within 120 min of irradiation, respectively. Photocurrent, Mott-Schottky, and EIS experiments proved the production, effective separation, and transmission of photo-active species in the presence of RGO/Gd@WO3 as compared to Gd@WO3 and WO3. Given the electrochemical testing and optical analysis, the photocatalytic mechanism is anticipated for the high photocatalytic activity of RGO/Gd@WO3. The novel RGO/Gd@WO3 photocatalyst proved to be a superior photocatalytic material for the photodegradation of organic pollutants.

Accelerated Indirect Photodegradation of Organic Pollutants at the Soil-Water Interface.

Indirect photolysis driven by photochemically produced reactive intermediates (PPRIs) is pivotal for the transformations and fates of pollutants in nature. While well-studied in bulk water, indirect photolysis processes at environmental interfaces remain largely unexplored. This study reveals a significant acceleration of indirect photodegradation of organic pollutants at the soil-water interface of wetlands. Organic pollutants experienced ubiquitously enhanced indirect photodegradation at the soil-water interfaces, with rates 1.41 ± 0.01 to 4.27 ± 0.03-fold higher than those in bulk water. This enhancement was observed across various natural and artificial wetlands, including coastal wetlands and rice paddies. In situ mapping indicated that soil-water interfaces act as hotspots, concentrating both organic pollutants and PPRIs by 9.30- and 4.27-folds, respectively. This synchronized colocation is the primary cause of the accelerated pollutant photolysis. Additionally, the contribution of each PPRI species to pollutant photolysis and a coupled transformation pathway at the soil-water interface significantly differed from those in bulk water. For instance, the contribution of singlet oxygen to metoxuron photolysis increased from 10.1% in bulk water to 44.4% at the soil-water interface. Our study highlights the rapid indirect photolysis of organic pollutants at the soil-water interfaces, offering new insights into the natural purification processes in wetlands as "Earth's kidneys."

Modified Titanium Dioxide Nanoparticles for Photocatalytic Splitting of Water and Its Application in Environmental Remediation as a Potential Alternative

Herein we reviewed Titanium dioxide (TiO2) nanoparticles and how they are applied in the photocatalytic splitting of water to generate hydrogen but also to remove both organic and inorganic pollutants. Hydrogen generation through the splitting of water by TiO2 which is a cheap, efficient, and non-toxic photocatalyst has found wide application in clean energy production. The efficiency of the photocatalyst can be improved by using water or sacrificial agents as electron donors, thereby enhancing hydrogen production. In addition, this review explores the fundamental principles, mechanisms, and applications of TiO2-based photocatalysis. It further, highlights the structural properties, bandgap engineering, and surface modifications that influence the catalytic activity of TiO2. Additionally, we discuss the doping of TiO2 with both metals and non-metals to narrow the energy band gap which lowers the recombination effects. Finally, it introduces the potential applications of TiO2-based photocatalysis in the photodegradation of organic and inorganic pollutants.

Highly efficient Zn(O,S)/Mo(O,S)2 oxysulfide heterostructure photocatalyst for organic pollutant degradation

Environment and energy are presently some of the highest priority topics for mankind that need to be addressed. Organic pollutants are toxic and carcinogenic for human and aquatic life hence their presence in water even in low concentrations can cause serious health problems. Photodegradation of organic pollutants by utilizing oxide-based heterostructure photocatalysts is the promising approach to carry out remediation efficiently ascribed to the advanced optoelectronic and structural superiority of oxide photocatalysts. The Zn(O,S)/Mo(O,S)2 composites were synthesized via a facile solvothermal method at low temperatures. Several methods were used to characterize the composite morphology, structure, electrical conductivity, chemical composition, and optical characteristics. The heterostructured Zn(O,S)/Mo(O,S)2 oxysulfide was employed successfully in the photocatalytic degradation of organic pollutants. Among the as-prepared samples, the 30-ZnMoOS composite catalyst was found to have the highest photodegradation performance on various organic dye pollutants. The photocatalytic activity of the as-synthesized Zn(O,S)/Mo(O,S)2 samples was assessed on the photodegradation of different kinds of organic dyes under visible light irradiation. The photocatalytic degradation efficiency of 30-ZnMoOS composite over 10 ppm neutral red (NR), methylene blue (MB), rhodamine B (Rh B), and methyl orange (MO) was found to be 99.6 %, 99.9 %, 99.5 %, and 98.8 % within 40, 45, 180, and 180 min, respectively, under visible light illumination. In the present photocatalytic system, the superoxide (.O2-) anions, hydroxyl (.OH) radicals, and holes (h+) are proposed to be the direct reactive species causing the photodegradation of organic dyes.

Photo-assisted Fenton degradation of tetracycline hydrochloride with magnetic Fe3S4/CuS composite

In recent years, semiconductor materials have gradually become popular through photodegradation of organic pollutants, and the semiconductor materials Fe3S4 and CuS have their own shortcomings. To make both materials useful, Fe3S4/CuS composites were prepared by hydrothermal method and degradation experiments were carried out using tetracycline hydrochloride (TCH) as a simulated pollutant. The effects of factors such as the mass ratio of Fe3S4 to CuS, temperature, pH changes, the consume of H2O2, and the amount of catalyst added on the degradation of TCH were explored. At room temperature, the Fe3S4/CuS composites exhibit good Fenton degradation efficiency. The F1C1.5 composite (mass ratio of Fe3S4 to CuS is 1:1.5) achieved 74.60 % at pH 4.0 within one hour. Subsequently, the free radical capture experiments and metal leaching experiments were conducted, and it was found that the active substance h+ played a major role. At the same time, the F1C1.5 composite shows stability, allowing for a lower concentration of iron leaching and having high catalytic activity after 5 cycles. These degradation properties, together with the ease of fabrication of the catalyst, will facilitate the practical application of this system in the continuous removal of TCH.

Constructing AlOOH-PVA/ZIF-67/AgCl/Ag composite membrane for the efficient photodegradation of organic pollutants under visible light irradiation

This study effectively fabricated photocatalytic membranes (∼5 cm diameter) assembled by γ-AlOOH-PVA (BOP) decorated heterostructural ZIF-67/AgCl/Ag composites by combing seeded secondary growth and photoreduction methods. First, the ZIF-67-seeded BOP membrane was shaped in a petri dish, followed by submerging in a 2-methylimidazole ligand for secondary growth to obtain the BOP/ZIF-67 membrane. Next, AgCl/Ag was formulated on the membrane by dipping it in an AgNO3 solution, followed by a photoreduction under visible LED light, resulting in a BOP/ZIF/AgCl/Ag membrane. The characterization showed that the membrane contained heterostructures of ZIF-67/AgCl/Ag anchored onto the BOP membrane. The BOP/ZIF/AgCl/Ag composite membranes exhibited enhanced light absorption and appeared the localized surface plasmon resonance (LSPR) of Ag0, giving it a bandgap energy of ∼2.10 eV. Photodegradation under visible LED light irradiation showed that the BOP/ZIF/AgCl/Ag membrane efficiently removed tetracycline (TC) and Rhodamine B dye (RhB) with corresponding degradation efficiency of ∼99% (90 min) and ∼95% (140 min), giving reaction rates of ∼0.046 min−1 and 0.019 min−1, respectively. The photocatalytic mechanism and photodegradation pathways analyses provided insights into the degradations of organic pollutants. Significantly, the designed BOP/ZIF/AgCl/Ag membrane quickly recovered from the solution and was of good durability. The study provided an effective strategy for constructing heterostructural ZIF-67/AgCl/Ag composite membranes, which are efficient and eco-friendly photocatalyst materials.

Cr3+doped α-Fe2O3 nanoparticles for photodegradation of organic pollutants with their disinfection efficacy

Pristine and Cr-doped α-Fe2O3 nanoparticles were synthesized using a low-cost and simple one-step hydrothermal method without any precipitating agent. Cr-doped α-Fe2O3 was found to be a promising candidate for recyclable photocatalytic application for Tetracycline (TC) and Congo-red (CR) degradation under normal sunlight irradiation along with excellent antibacterial properties. Addition of Cr shows a significantly improved degradation efficiency from 20% to 91% in just 25 min for CR, while the degradation rate reached to 81% for TC, which was also monitored in real-time using internet of things (IoT). Also, a high degree of mineralization was achieved (∼87.9%), which was confirmed using total organic carbon (TOC) content. In parallel, the biochemical oxygen demand/chemical oxygen demand (BOD5/COD) ratio confirmed the fast degradation efficiency using a small amount of catalytic dosage (∼ 0.40 g/L). Also, degradation of multiple dyes provides a promising avenue for addressing complex waste water treatment challenges. Moreover, Cr-doped α-Fe2O3 displays excellent antibacterial activity towards E.coli and E.Faecium. Major factors involved in sunlight driven photocatalytic activity for example absorbance range, porosity, separation between e--h+, and charge transfer property were surprisingly improved by Cr doping and henceforth increased photocatalytic activity and antibacterial properties. This work highlights the potential utilization of Cr-doped α-Fe2O3 for the purification and disinfection of industrial waste water.

Iron mediated n → π* electron transitions and mid-gap states formation in CN under low-temperature secondary calcination enhances photodegradation of organic pollutants

Iron modified carbon nitride (CN) materials have attracted widespread attention from researchers in different application fields. In this paper, single atom iron anchored CN (FeCN) with mid-gap states and n → π* electron transition was synthesized through low temperature secondary calcination. The mid-gap states introduce surface states capable of trapping photogenerated electrons, enabling FeCN to absorb photons with energies lower than its intrinsic optical bandgap. 10%FeCN also exhibits distinct optical absorption above 490 nm derived from the n → π* electron transition, which expand the visible light response range of photocatalysts and enhance electron transport ability. Additionally, the Fe-Nx site enhances the separation and transmission efficiency of photoexcited charges. The prepared 10%FeCN exhibits extremely high photocatalysis and photo-Fenton activity. Mercaptobenzothiazole (MBT) degradation rate of 10%FeCN is 3.47 times higher than CN, achieving a mineralization rate of 86.7% in 100 min. Additionally, the oxytetracycline hydrochloride (OTC) degradation rate of 10%FeCN in photo-Fenton reaction is 11.9 times higher than CN. After five cycles, this catalyst still has good reactivity, indicating its good stability.

Green synthesis of Z-scheme CeO2 decorated ZnO nanocomposites for photodegradation of organic pollutants, antioxidant activity and its effects on seed germination

The present work aimed to report a green synthesis of CeO2@ZnO nanocomposites via co-precipitation method using azadirachta indica aqueous leaf extract. The characterization of the prepared CeO2@ZnO nanocomposites were done using XRD, FTIR, SEM, EDAX, UV–vis, and PL techniques to examine the structural properties, functional group, morphological and electronic properties. As prepared CeO2@ZnO nanocomposites have been used for photo degradation of Crystal Violet (CV), Methylene blue (MB) and Rhodamine B (RhB) dyes in presence of solar light in aqueous solution. From structural analysis the mean crystallite sizes of the synthesized nanocomposites varied from 27 nm to 9 nm. The degradation of MB, CV and RhB dyes follows pseudo-first order reaction rate with the rate constantsk1 for MB is 10.09 × 10−3 min−1, k1 for CV is 8.71 × 10−3 min−1, k1 for RhB is 0.92 × 10−3 min−1.The characterized nanocomposites were used for seedling growth, physiological and biochemical responses during seed germination. In CeO2@ZnO nanocomposites treatments, significantly higher values of shoot length and root length were observed in CZ1 (0.5, and 1 mg/ml) treated seedlings as compared to other samples. Similarly, the activities of ɑ-amylase and protease enzymes were recorded to be maximum for CZ1 nanocomposites. For instance, the increased activity of α-amylase was observed to be 2.12, 2.09, and 1.33 folds higher in CZ1, CZ2, and CZ3 (1 mg/ml) treated seedlings as compared to the control. Similarly, the protease activity was reported to be increased by 0.011 folds in CZ1 nanocomposites (1 mg/ml) treated seedlings as compared to the control. Furthermore, all the CeO2@ZnOnanocomposites have excellent DPPH, and ABTS free radical scavenging activities, confirmed by the Ferric-Reducing Antioxidant Power (FRAP) assay. The CZ1 nanocomposites showed the best results. The CeO2@ZnO nanocomposites were found to have no toxic effects on cellular division confirmed with improved mitotic index under different treatment regimens.

Antibacterial of PSf substrate and PA active layer of TFN membrane made by POM/3-API hybrid in situ FO separation performance and photo-degradation of organic pollutant

Membrane bacterial studies are stable in modified FO membrane that shows superior antibacterial activity against Tetrasphaeria (minimal inhibitory concentration (MIC) = 0.00350, 0.11 μg/mL). Due to augmented interventions of the containments in the water resources, essential novel hybrids construct of polyoxometalate with imidazole for the separation process and photo catalytic degradation of organic pollutants have been recognized and scouted in this paper. This work demonstrated the separation and photocatalytic extraction of the organic pollutants from the potable and waste water using organo-polyoxometalate ionic salts as hybrids designated as polyoxometalate with 3-(aminopropyl) imidazole (POM/3-API). Hybrid materials are strategically prepared in one-pot via counter acidic proton exchange between POM (O- ions) which tends to move towards N- containing organic molecules, which are doped with manganese (IV) ions. Scanning Electron Microscope (SEM) studies show physico-chemical adsorption of the hybrids, PSf substrate and on PA layer of membranes, proving the multifunctional surface characteristics morphological formation. In addition, POM/3-API hybrids were synthesized via shock acoustic that reveals higher permeate flux through separation process and almost disappears (PAPI-1: 81.4 %) with MO during degradation process. Remarkably, the morphological changes of observed shapes before and after MO clearly show an effective performance, as was definite by the successful interfacial polymerization between membrane and POM/3-API. These help towards elimination of MO dyes at waste water sources, making the process environment-friendly.

Intrinsically microporous polyimide-based metal-free catalysts for round-the-clock photodegradation of organic pollutants

Photocatalytic degradation of organic pollutants is an essential technology for various environmental applications. However, the effectiveness of most photocatalysts is restricted to light. Herein, we report metal-free catalysts derived from intrinsically microporous polyimide for persistence in photocatalytic degradation of dyes. We systematically investigate the effect of porosity and functionality on photocatalytic efficiency. Both the pristine 4,4′-(hexafluoroisopropylidene)diphthalic anhydride-3,3′-dimethylnaphthidine and its thermally annealed counterpart at 530 °C exhibit high charge storage capabilities, enabling continuous photodegradation in the absence of light. The pre-irradiated catalyst exhibits an approximately 99% degradation of the dye, with a ~40% improvement relative to the non-pre-irradiated sample. We studied the influence of the chemical structure and porosity on the photocatalytic degradation efficiency in darkness by varying the polyimide chemical structure using different diamines. This research underscores the potential of polymers with intrinsic microporosity for application in the continuous degradation of dyes, contributing to the pursuit of cleaner water.

A novel kind of hollow SiO2@g-C3N4@TiO2 microspheres for rapid removal of dyes and antibiotics in water under sunlight

In this paper, using PVP-modified polystyrene microspheres as template, tetrabutyl titanate (TEOT), tetraethyl orthosilicate (TEOS) and melamine as precursor, we developed a facile one-pot two-step method to preparing a novel kind of mesoporous hollow SiO2@TiO2@g-C3N4 ternary composite microspheres with plush surface, in which highly active black titanium dioxide (TiO2) was formed by simple calcination without further chemical reduction treatment. The structure and morphology of the composite microspheres were detailed characterized for understanding the formation mechanism. Research results indicated that the hollow SiO2 microspheres can promote the formation of oxygen vacancies in TiO2, and the ternary combination narrowed the bandgap width of the black hollow composite microspheres to 1.43 eV, thus endowing it with excellent broad-spectrum catalytic performance for rapid photo-degradation of persistent organic pollutants (POPs) such as dyes and antibiotics in water under sunlight. The removal rates of dyes reached more than 70 %, as well as that of antibiotics more than 50 % within one hour. Finally, a plausible catalytic degradation mechanism was discussed.

Facile synthesis of SrO/CeO2/alginate nanocomposite for the photocatalytic degradation of reactive red 195 dye and CO2 capturing

The SrO/CeO2/ALG nanocomposite was successfully constructed by using the co-precipitation method and was analyzed with zeta potential, FTIR, SEM, XRD and BET techniques. A common Azo dye, namely Reactive Red 195, widely utilized in the dyeing industry and causing environmental pollution, was chosen to examine the photodegradation of SrO/CeO2/ALG nanocomposite, and it was shown that this dye could be successfully degraded by prepared nanocomposite. Impacts of factors such as pH, contact time and effect of different concentrations of dye and catalyst, the effect of scavengers and the effect of hydrogen peroxide were investigated to find out degradation efficiency. This SrO/CeO2/ALG nanocomposite was used for the photodegradation of reactive red 195 dye and 93 % degradation efficiency was obtained at pH 3, 6 mg of catalyst concentration, dye concentration of 10 ppm, and contact time of 90 min. Degradation kinetic studies were determined by applying first-order and Langmuir-Hinshelwood reactions. The results exhibit a novel method for the synthesis of nanocomposite to effectively cause photodegradation of organic pollutants from wastewater and can be applied to industrial manufacture. The mesoporous SrO/CeO2/ALG nanocomposite also captured 4.31 and 2.98 mmol/g CO2 at 25 and 40 °C temperatures, respectively.

An effective strategy for synthesizing high-performance photocatalyst by recycling the graphite target wastes

The tide of new energy vehicles and modern semiconductor devices releases a myriad of graphite anode and graphite target wastes. Recycling graphite wastes for catalysis preparation turns out to be a win-win and efficient way to deal with rampant environmental pollution. In this work, a graphite target waste was efficiently recycled into 2D few-layer graphite as the raw materials for the subsequent synthesis of nanoscale photocatalysts. The as-developed photocatalyst demonstrates a gain of 19 % in photocatalytic efficiency and superior photostability in sunlight-driven photodegradation of organic pollutants. Furthermore, the impact of temperature and pH value on the photocatalytic degradation efficiency was systematically investigated. The work affords an effective strategy for high-efficiency waste reclamation through full utilization of the graphite target wastes.

Green biosynthesized N-doped CuO@Zeolite nanocomposite for the efficient photodegradation of toxic organic pollutants from wastewater

Nanotechnology is one of the most advanced methods available for the degradation of toxic pollutants from the environment. Specifically, nanoparticles generated with plant extracts are more stable and biocompatible than those produced using traditional chemical and physical processes. The current study focuses on the green synthesis of N-CuO@Zeolite nanocomposite with Camellia sinensis (green tea) leaf extract. The green synthesized nanocomposite was used for the photocatalytic degradation of hazardous organic pollutants, including Auramine-O (AO) and yellow color textile industrial dye (YD). Under direct sunlight irradiation, synthesized nanomaterials exhibited excellent photocatalytic activity for AO and YD degradation. The best conditions for photocatalytic degradation were found to be pollutant concentrations of 2 mg L−1 for AO and 6 mg L−1 for YD, photocatalyst dosages of 15 mg for both AO and YD, and neutral pH for both pollutants. Within 150 minutes, the synthesized N-CuO@zeolite nanocomposite attained degradation efficiencies of 95 % for AO and 92 % for YD, compared to its parent materials N-CuO (80 % for AO and 76 % for YD) and CuO (68 % for AO and 65 % for YD). The degradation rates of both pollutants were accurately described by first-order kinetics, consistent with the Langmuir adsorption model. Additionally, the ecologically sustainable novel N-CuO@Zeolite nanocomposite illustrated superior reliability and reusability, keeping photocatalytic efficiency even after ten cycles of constant utilization, and its long-term stability was confirmed by PXRD analysis after processing. The material's excellent reusability and stability emphasize the nanocomposite's potential as a long-term solution for industrial wastewater treatment applications.

TiO2/Al-PILC Catalysts Synthesized from a Non-Conventional Aluminum Source of Aluminum and Applied in the Photodegradation of Organic Compounds

AbstractThis study explores the transformative potential of Pillared InterLayered Clays (PILC) derived from non-conventional aluminum sources as catalytic supports in the synthesis of TiO2/catalysts for the efficient photodegradation of organic pollutants in water. Montmorillonite (Mt) and three alumina-pillared montmorillonite (PILC) synthesized using various aluminum sources, were impregnated with titanium to synthesize TiO2/catalysts. The successful synthesis of these materials was confirmed through several characterization techniques such as X-ray diffraction (XRD), N2 adsorption-desorption at -196 ºC, morphological analysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and Energy-Dispersive X-ray Spectrometry (EDX). The photolysis, adsorption, and catalytic behavior of the TiO2/catalysts were studied for the degradation of triclosan (TCS), 2,6-dichlorophenol (2,6-DCP), and bisphenol A (BPA). All synthesized catalysts surpassed the efficacy of commercial anatase, with TiO2/Al-PILC exhibiting superior performance in comparison to TiO2/Mt. Photodegradation was most effective under UV radiation, with TCS demonstrating the highest degradation (approximately 70%). Notably, Al-PILC samples, particularly those synthesized from saline slags, displayed enhanced properties. Among them, TiO2/Al-PILCAE exhibited the highest degradation rates under both UV and visible light, underlining the remarkable potential of saline slags as precursors for Al-PILC synthesis. This study provides valuable insights into the design and development of efficient catalysts for water treatment applications, paving the way for sustainable and effective solutions in the realm of environmental remediation.

GO/Bi2O2CO3/NiWO4 with Z-scheme heterojunction: Efficiently enhanced degradation of organic pollutants under visible light and DFT studies

A ternary composite of GO/Bi2O2CO3/NiWO4 (GBCNWO) was prepared via an in-situ of Bi2O2CO3 onto the surface of NiWO4 and Bi2O2CO3/ NiWO4 being warped by GO, which was thereafter untilled as catalyst in photodegradation of organic pollutants. The microstructure, and optical properties of all the prepared samples were characterized using various techniques such as XRD, FT-IR, SEM, TEM, TG-DTG, XPS, UV-Vis, ESR, and N2-adsorption. Amongst the studied samples, GBCNWO possessed the largest specific surface area, which would efficiently afford much more spaces for the exposing of active sites. Results of UV–vis and XPS suggested that GBCNWO was more efficient for the adsorption and conversion of visible light, and photocurrent conduction through graphite carbon ring could lessen the recombination rate of photoelectrons and holes. Also, the minor arc radius of GBCNWO unveiled its lowest photoresistors among the composites, indicating that the GBCNWO structured with GO, Bi2O2CO3 and NiWO4 has synergistic catalysis in the photodegradation. Importantly, 95.15 % of degradation rate was observed under the optimized conditions (pH=7, catalyst weight of 30 mg, 40 mg/L of MB, 25 °C). Additionally, the degradation rate of various substrates followed the order: MB (99.34 %) > ciprofloxacin (97.28 %) > RHB (97.01 %) > indole (27.47 %) > phenol (9.47 %). The quenching experiment and ESR test suggested that three kinds of active species (•OH, •O2− and h+) can be photogenerated during visible light radiation. Among them, •O2− was confirmed as the key species during the photocatalytic process, which could be adduced that the existence of oxygen vacancies made the receiving photoelectrons to reduce O2, forming the superoxide radical. Finally, a Z-scheme mechanism about the production of active radicals was proposed, which was also validated by DFT calculations.

Sonochemical assembly of dual-sized 2D/2D BiYO3/BiOBr Z-scheme heterojunction for efficient photodegradation of organic pollutants

Possessing active sites, tunable band gaps and short charge transfer paths, 2D/2D heterojunctions with face-to-face contact are considered to be one kind of promising photocatalysts. Herein, typical 2D/2D structured BiYO3/BiOBr photocatalysts have been fabricated via an electrostatic self-assembly route. When used to degrade Congo red, the heterogeneous composite with the mass ratio of BiYO3 to BiOBr as 1:1 exhibits the highest photocatalytic degradation efficiency and kinetic rate respectively of 90.14 % and 0.0108 min−1. In addition, it demonstrates excellent performance in degrading other organic pollutants, as the removal efficiencies can attain 97.25 % (Rhodamine B), 96.03 % (malachite green) and 99.05 % (butyl xanthate), respectively. Electrochemical and photoluminescence results indicate that BiYO3 and BiOBr can combine well to form a heterojunction structure to inhibit the recombination of photogenerated electron-hole pairs and improve the transport efficiency. The results of energy band structure analysis, trapping experiment and electron spin resonance (ESR) confirm the formation of Z-scheme heterojunction between BiYO3 and BiOB rather than type II ones.

Bismuth‐based metal‐organic frameworks and derivatives for photocatalytic applications in energy and environment: Advances and challenges

AbstractPhotocatalysis is an environmentally friendly technology for the utilizations of solar energy and has garnered significant attention in both scientific and industrial sectors. Developing cost‐effective semiconductive materials is the core issue in photocatalysis. Bismuth‐based metal‐organic frameworks (Bi‐MOFs) have emerged as attractive candidates in various photocatalytic applications, and Bi‐MOFs derivatives further expand and consolidate their promising potential in the realm of photocatalysis. Various modification strategies including in‐situ tailoring or external doping, as well as meticulous design and selection of metal nodes and organic linkers allow for fine control over the surface multifunctionality in Bi‐MOF‐based and derived photocatalytic composites with adjustable energy band structures and enhanced photocatalytic performance. In this review, the recent progress in the synthesis of diverse Bi‐MOFs‐based materials, Bi‐MOFs derivatives, and their Bi‐containing semiconductive composites were systemically analyzed and reviewed. The state‐of‐the‐art research progresses in the applications of Bi‐MOFs and derivatives, as well as composites in photocatalytic water splitting for hydrogen production, photodegradation of organic pollutants, and photocatalytic carbon dioxide reduction are comprehensively summarized. The relationships between structures, properties, and photocatalytic performance of Bi‐based semiconductive composites are discussed in detail. In addition, the perspectives and future challenges on Bi‐MOFs‐based and derived materials for photocatalytic applications are also offered.

Nghiên cứu tổng hợp vật liệu composite SiO2/g-C3N4 cho quá trình quang xúc tác phân hủy rhodamine B

In this study, a visible-light-driven SiO2/g–C3N4 composite was prepared by heating a mixture of SiO2 and urea. The products were characterized by X-ray diffraction (XRD), infrared spectra (IR), scanning electron microscopy (SEM), and ultraviolet–visible diffuse reflectance spectroscopy (UV-Vis DRS). Results indicate that the composite only contained SiO2 and g-C3N4, and the SiO2/g–C3N4 composite had higher photocatalytic activities in the degradation of rhodamine B (82.2%) compared to the pristine g-C3N4 (43.9%) under visible light. The SiO2/g–C3N4 composite is a promising new material for the photodegradation of organic pollutants in wastewater due to its high photocatalytic performance, low cost, and convenient collection for reuse.