Photocatalysts For Applications Research Articles

Immobilized Eosin Y on Modified Silica Nanoparticles and their Applications in Organic Synthesis

AbstractThe development of novel photocatalytic systems is crucial for advancing sustainable chemical processes in organic synthesis. In this study, we report the preparation, characterization, and application of a heterogeneous photocatalyst based on Eosin Y (EY) covalently immobilized on silica nanoparticles (SNPs). The SNPs‐EY photocatalyst was thoroughly characterized using various techniques, including SEM, TEM, X‐ray diffraction, UV‐vis diffuse reflectance spectroscopy, solid‐state fluorescence spectroscopy, XPS, FT‐IR, TGA, and DLS. These analyses confirmed the successful immobilization of EY on SNPs and demonstrated the uniformity and favourable photophysical properties of the resulting hybrid material. The photocatalytic performance of SNPs‐EY was evaluated in a series of model reactions, including aza‐Henry reaction (cross‐dehydrogenative coupling), reduction of nitrocompounds, and photooxidation of dimethylanthracene. The reaction results demonstrated that SNPs‐EY is an effective and recyclable photocatalyst, offering yields comparable to or higher than those of homogeneous systems, while providing the advantages of easy separation and reuse. This study highlights the potential of SNPs‐EY as a versatile photocatalyst for various organic transformations, promoting the advancement of green and sustainable chemistry.

Photocatalytic Degradation of PCB 153 Using Fe3O4@SiO2@TiO2‐Co Core‐Shell Nanocomposite

AbstractThis study investigates the photocatalytic degradation of PCB 153 using Fe3O4@SiO2@TiO2‐Co core‐shell nanocomposites under LED irradiation. The unique core‐shell structure, incorporating a magnetic Fe3O4 core, a protective SiO2 layer, and a photoactive TiO2 shell doped with Co, enhances light absorption, charge separation, and stability. The effects of various parameters, including catalyst dosage, initial pollutant concentration, solution pH, H2O2 concentration, reaction time, and cosolvent type, were investigated to optimize the degradation process. The results demonstrated the high efficiency of the Fe3O4@SiO2@TiO2‐Co nanocomposite in degrading PCB 153, with a maximum degradation efficiency of 95.2% under optimal conditions. The magnetic properties of the Fe3O4 core enable easy separation and recovery of the catalyst, making it a sustainable and cost‐effective solution. This study provides valuable insights into the design and application of advanced photocatalysts for environmental remediation.

Schottky junctions integrated with S-scheme heterojunctions in recyclable loaded ZnIn2S4/UiO-66/calcined graphite felt photocatalysts with enhanced carrier separation for photocatalytic degradation

Photocatalytic technology holds significant potential in the purification of antibiotic wastewater. However, efficient carrier separation and convenient recyclability are crucial for the practical application of photocatalysts. Herein, a loaded ZnIn2S4/UiO-66/calcined graphite felt (ZU/C-GF) composite photocatalyst was demonstrated to achieve efficient and stable removal of tetracycline hydrochloride (TCH) from water. Detailed characterization and theoretical calculations suggested that ZnIn2S4 could form a Schottky junction with C-GF and an S-scheme heterojunction with UiO-66. The internal electric field (IEF) at the interface could promote the migration of photoelectrons, while the Schottky barrier could inhibit electron backflow. This synergistic strategy maximized the separation of photogenerated electrons and holes, thereby enhancing the photocatalytic performance. The optimal composite material exhibited the highest removal efficiency (97.0 %) and reaction rate (0.02312 min−1) while maintaining comparable degradation performance under solar irradiation. Additionally, this C-GF-based immobilization scheme allowed for rapid recovery and reuse of the photocatalyst, effectively addressing the challenge of recycling. ZU-10/C-CF demonstrated stable reusability after five consecutive cycles, revealing its significant potential for practical applications. This work presents novel insights for coupling Schottky junctions and S-scheme heterojunctions, and describes a more convenient approach for the continuous and stable treatment of antibiotic wastewater.

Facile construction of multifunctional Cu2O@ZnIn2S4 heterojunction with accelerated charge transfer for efficient photocatalytic treatment of tetracycline (TC) under visible light irradiation, DFT calculations

The extensive applicability and remarkable stability of nano-semiconductor photocatalysts are of paramount importance for advancing the field of efficient water treatment. This study presents, Cu2O@ZnIn2S4 photocatalytic materials with type II heterostructure were prepared by indium zinc sulfide capping technology to degrade tetracycline. Characterization results indicated that the degradation rate of tetracycline hydrochloride (TC) could achieve 99.2 % under simulated aqueous environmental conditions, maintaining a degradation rate exceeding 85 % after five cyclic stability tests. Concurrently, the constructed type-II heterojunction effectively enhanced the transient photo responsiveness of the catalyst, facilitating the rapid transfer of photogenerated electrons. Furthermore, the structural configuration of the parceled ZnIn2S4 lamellae acted as a photon trap, minimizing the reflection of incident light and augmenting light utilization efficiency. The inherent electric field of the heterojunction significantly facilitated the degradation of TC, while the nanosheet architecture and surface porosity of the catalyst contributed to enhanced mass transfer capabilities, as corroborated by density-functional theory calculations and band gap analysis. This study utilized Cu2O@ZnIn2S4 as an efficient photocatalyst for water treatment, thereby offering a viable approach for practical applications of the catalyst.

Visible-light driven S-scheme Bi2WO6/graphitic carbon nitride heterojunction for efficient simultaneous removal of TC and Cr(VI)

The application of photocatalysts in water governance has attracted extensive attention, and past research efforts often focused on single pollutant removal. Simultaneous removal of multiple pollutants from wastewater by a single processing unit is highly desirable, realistic, and challenging. The use of band-matched semiconductors to form heterojunctions is an important way to achieve this technology. In this work, we have designed a Bi2WO6/g-C3N4 heterojunction via an in-situ growth method. The in-suit XPS was used to verify the electron transfer pathway which conforms to the S-scheme mechanism. Under visible light irradiation, the removal rates of Cr(VI) and TC are 97.7 % and 96.0 % respectively. In addition to the excellent photocatalytic performance, the catalyst showed a high degree of stability during the five cycles. The formation mechanism of S-scheme heterojunction is discussed based on DFT calculation and physicochemical characterization. Liquid chromatography-mass spectrometry (LC-MS) and Quantitative Structure-Activity Relationship (QSAR) were used to analyze and predict the degradation pathways, intermediates, and toxicity. The efficient performance of the photocatalyst is attributed to the more efficient photogenerated charge transfer efficiency brought about by the formation of the built-in electric field, and the improvement of the photogenerated carrier recombination rate to provide more reactive sites with a large specific surface area. We provide a practicable strategy for the efficient treatment of inorganic and organic co-pollutants in environmental water by constructing an S-scheme heterojunction photocatalyst.

Biogenic fabrication of α-h Phase 2D-MoO3 nanomaterials: Comprehensive analysis of physicochemical and impedance properties for biological and photocatalytic applications

The design of high aspect ratio nanomaterials for environmental remedies is gaining attention, mainly through eco-friendly approaches. This study presents the first-ever report on the green preparation of molybdenum oxide nanoparticles (MoO3 NPs) using a leaf extract derived from Eucalyptus. XRD and Rietveld refinement analysis confirmed the effect of calcination temperature in obtaining the α- and h- phases of MoO3 NPs. The FTIR analysis revealed the functional group characteristics of MoO3 NPs. By the influence of Eucalyptus extract mediation, FE-SEM images showed the hexagonal shape of MoO3 NPs with well-organized 2D rod-like structures mediated by the Eucalyptus extract. The h-MoO3 nanocrystalline materials with a higher concentration (100 mg/µL) demonstrated exceptional antioxidant and antibacterial characteristics against multi-drug-resistant bacteria, specifically S. aureus and E. coli. The photocatalytic activity for the dye degradation process was investigated with measurement of MoO3 NPs point-of-zero charges against different pH (1.8, 3.8, and 5.8) and (3.7, 5.7, and 7.7) of Rhodamine B and Brilliant Blue dye solution. The precise point of zero-charge of MoO3 NPs degraded 99.08% of Rhodamine B dye within 90 min, with a 4.98 × 10−2 min−1 degradation rate. The cost-effective and environmentally friendly method for the production of 2D MoO3 nanocrystalline rods demonstrates excellent catalytic performance and introduces a novel framework for advancing photocatalyst applications.

Preparation and degradation efficiency of CeO2 and CdS composite photocatalysts

Cerium dioxide (CeO2) is an extremely versatile rare-earth oxide, which is chemically stable, nontoxic, and simple to prepare, making it of great interest in the field of photocatalysis. However, cerium dioxide has a low forbidden band width, its utilization of sunlight is not high, and the However, cerium dioxide has a low forbidden band width, its utilization of sunlight is not high, and the photogenerated carriers are very easy to compound. These problems lead to the low photocatalytic efficiency of cerium dioxide, which greatly limits the practical application of cerium dioxide photogeneration. These problems lead to the low photocatalytic efficiency of cerium dioxide, which greatly limits the practical application of cerium dioxide photocatalysts. morphologies was prepared by hydrothermal method using cerium nitrate as raw material, and then compounded with CdS to form a composite photocatalyst. The effect of morphology on the degradation efficiency of CeO2 and the change of the degradation efficiency of CeO2 with different morphologies after The effect of morphology on the degradation efficiency of CeO2 and the change of the degradation efficiency of CeO2 with different morphologies after compounding with CdS were investigated.

Construction of Bi2MoO6 sheets/NH2-UiO-66(Zr) heterojunction photocatalysts toward enhanced degradation of tetracycline under visible light

The application of photocatalysts in environmental field has emerged as a prominent research topic. Nevertheless, the efficiency of photocatalysts is reduced as the recombination of photogenerated chargers significantly, restricting their extensive use in this domain. In the present study, photocatalysts composed of bismuth molybdate/NH2-UiO-66(Zr) (Bi2MoO6/NH2-UiO-66(Zr)) featuring Z-scheme heterojunctions were effectively synthesized using a two-step hydrothermal technique. These photocatalysts exhibit remarkable photocatalytic degradation under visible light conditions. Notably, the broad planar configuration of Bi2MoO6 sheets improves the separation of the photogenerated charge carriers. NH2-UiO-66(Zr) layered atop Bi2MoO6 sheets enhances the availability of catalytically active sites, reduces charge recombination, and promotes charge transfer through the interface. The kinetic rate constant for Bi2MoO6/NH2-UiO-66(Zr) is around 0.00329 L mg−1 min−1, indicating the increase of 3.78 and 41.13 times compared with pure Bi2MoO6 and NH2-UiO-66(Zr), respectively. The efficiency for photocatalytic degradation of tetracycline using Bi2MoO6/NH2-UiO-66(Zr) reaches 81.72 % under visible light. Importantly, this efficiency exhibits a reduction of 10 % after five recycling cycles, demonstrating notable stability. The photocatalytic mechanism involved in tetracycline degradation was uncovered through trapping experiments and EPR, indicating that it is predominantly facilitated by the active oxidation of ·O2- and ·OH. The intermediates of the photocatalytic process as well as the possible degradation pathways were discussed. The creation of Bi2MoO6 sheets/NH2-UiO-66(Zr) heterojunction photocatalysts provides a fresh approach to the development of novel catalysts, which may lead to significant advancements in environmental remediation efforts.

Synthesis of SrTiO3 nanoparticles for photocatalytic applications

Due to the heightened emphasis on environmental protection and the escalating demand for renewable energy sources, the potential applications of strontium titanate (SrTiO3) nanoparticles in photocatalysis have shown remarkable promise. With rapid advancements in technological capabilities, the standards for SrTiO3 photocatalytic materials have soared. Researchers have relentlessly delved into and innovated techniques for preparing strontium titanate powders, striving to yield nanocrystalline SrTiO3 that exhibits specific morphologies, high purity, superior dispersibility, and exceptional photocatalytic efficiency, while continually refining the properties of these powders. The paper encapsulates the advancements in preparation methodologies and photocatalytic attributes of perovskite SrTiO3 nanoparticles, encompassing diverse synthetic routes such as hydrothermal synthesis, sol-gel process, chemical precipitation, solid-state reaction, sonochemical technique, and composite modification strategies. The characteristics, merits, demerits, and prevailing challenges associated with each synthesis technique are thoroughly and analyzed. Ultimately, this review serves as a valuable reference and foundation for the synthesis, modification, and application of SrTiO3 nanoparticle photocatalysts, fostering their development and practical implementation in environmental remediation and renewable energy technologies.

A novel Ag/Bi/Bi2O2CO3 photocatalyst effectively removes antibiotic-resistant bacteria and tetracycline from water under visible light irradiation

Currently, achieving dual applications of Bi2O2CO3-based photocatalysts in photocatalytic degradation and sterilization under visible-light conditions is challenging. In this study, a novel Ag/Bi/Bi2O2CO3 visible-light photocatalyst with bimetallic doping and rich oxygen vacancies was successfully synthesized using a one-pot hydrothermal crystallization method. The existence of oxygen vacancies was verified by X-ray photoelectron spectroscopy (XPS) and Electron spin resonance (ESR) analysis. The experimental results showed that Ag/Bi/Bi2O2CO3 killed ∼100% (log 7) of antibiotic-resistant Escherichia coli (AR-E. coli) within 60 min and degraded 83.81% of tetracycline (TC) within 180 min under visible light irradiation. Moreover, Ag/Bi/Bi2O2CO3 can still remove 61.07% of TC in water after 5 cycles, showing excellent photocatalytic cycle stability and reusability. The possible degradation pathway of TC was determined by liquid chromatography-mass spectrometry. It was found that the main active substances in the photocatalytic disinfection of AR-E. coli were 1O2, h+, and ·OH, while 1O2 was the dominant active species in the photocatalytic degradation of TC. This study presents a promising Bi2O2CO3-based visible light photocatalyst for treating both antibiotics (TC) and antibiotic-resistant bacteria (AR-E. coli) in water.

Engineering Dual-Defective 0D/2D VN-CNQDs/VBi-Bi4O5Br2 S-Scheme Heterostructure for Boosting CO2 Photoreduction in Air.

The direct photocatalytic reduction of CO2 in air is the future trend of photocatalyst application. Herein, the 0D carbon nitride quantum dots with nitrogen vacancies (VN-CNQDs) and 2D bismuth-deficient Bi4O5Br2 (VBi-Bi4O5Br2) are integrated by hydrothermal method. The S-scheme heterostructure of VN-CNQDs/VBi-Bi4O5Br2 composite promotes the separation rate of photogenerated carriers and enhances the redox capacity. The dual defects provide a large number of adsorption and catalytic sites that enhance the ability to capture and reduce CO2. The synergistic effect of S-scheme heterostructure and defect engineering enables the efficiency of CO2 photoreduction to CO with VN-CNQDs/VBi-Bi4O5Br2 to reach 16.89µmolg-1h-1 in air and 55.69µmolg-1h-1 in VCO2: VAir = 3:1 condition, which is 17 and 21 times higher than that of Bi4O5Br2, respectively. The dual-defective VN-CNQDs/VBi-Bi4O5Br2 exhibits more lower energy barrier for forming *CO2, *COOH, and *CO and is easier to release CO gas. And it exhibits excellent cycling stability for photocatalytic CO2 reduction to CO. The photocatalytic reduction mechanism of CO2 to CO in the VN-CNQDs/VBi-Bi4O5Br2 S-scheme heterostructure is further analyzed. This work provides new perspectives for the design of the photocatalysts with defect engineering for efficient photoconversion at low CO2 concentrations.

Effect of oxygen vacancies on enhancing the photo-catalytic activity, photo-luminescence and electronic structure properties of nanostructured Y-doped CeO2

The exceptional characteristics of CeO2 and Ce1-xYxO2 (x = 0.03, 0.05 and 0.07) nanoparticles were reported in the manuscript supporting that Y3+replaces Ce3+/Ce4+leads to oxygen vacancies formation. The results of XRD measurements revealed FCC structure of decreased crystallite size of CeO2 with improved crystallinity. To investigate the surface morphology, HRTEM and SAED patterns were performed. EDX analyses were undertaken to discuss the elemental and compositional characteristics. The absorption spectra using UV–Vis–NIR spectroscopy were analyzed and red shifted absorbance was found to enhance with decreasing band gap values for increased Y doping. The Photoluminescence spectra depicted various emissions representing the development of various defects and oxygen vacancy with incorporation of Y content in the lattice with CCT values below 4000 K to be classified as warm yellow light for indoor applications. The development of oxygen vacancies in the CeO2 lattice was further supported by XPS measurements for core levels Ce 3d, O 1s and Y 3d. Furthermore, the XPS measurements also reported the valence states of elements, Ce with 3+ and 4+, Y with 3+ and O with 2- along with charged oxygen vacancies. The photo-catalytic analysis revealed that Y-doped CeO2 nanoparticles show better degradation using a variety of characterization. A degradation mechanism that illustrates the impact of oxygen vacancies created by Y-doping on the photo-degradation process has been proposed. The novelty of Y-doped CeO2 nanoparticles stems from their improved photo-catalytic activities, which are linked to structural changes and the formation of oxygen vacancies. This doping considerably affects the electrical structure, resulting in better light absorption and less electron-hole recombination. The detailed outcomes of present study suggested the use of Y-doped CeO2 nanoparticles in optoelectronics, spintronics devices and photo-catalyst applications.

In-Situ Oxidized MXene Dopes for Enhanced Sensitivity of PVDF Piezoelectric Nanogenerators in Morse Code Transmission and Photocatalysis Applications

The surface functionalization of MXenes with controlled termination groups alters various properties and expands its versatility. Here, we report a partially oxidized MXene-incorporated polyvinylidene difluoride (PVDF) fibrous piezo-nanogenerator mats termed as MOP performing functions of biomechanical energy harvesting, self-powered tactile sensing, and piezo-assisted photocatalyst application. In comparison with neat PVDF, MOP piezo nanogenerators (PENG) with 5 wt% dope (MOP(5)-PENG) show significant improvement in the output performance delivering an output voltage, current, and power density of 14.4 V, 1.6 μA, and 1.5 μW cm-2, respectively. The device reveals a high sensitivity of 3.7 V/KPa to tactile perceiving, which was applied for digital information transmission. The addition of oxidized MXene increases not only the β crystallinity of fibers but also their dielectric property which was attributed to the semi-conductive TiO2 formed during in-situ oxidation process. Moreover, the composite fibers can be employed as piezo-photocatalyst (PPC) for the degradation of Rhodamine B dye. The synergetic effect of light and piezoelectric action significantly improved the kinetics of degradation. A heterojunction formed between TiO2 and MXene further boosted the separation of photo-generated species and produced more active species for effective degradation up to 98%.

Z-scheme heterojunction TNCoPc/BiOBr nanomicrospheres for efficient photodegradation of tetracycline and rhodamine B: Degradation performance, intrinsic mechanism and degradation pathway studies

The natural ecosystem has been significantly jeopardized due to the misuse of organic dyes and antibiotics. To treat organic wastewater safely and efficiently, this study synthesized a binary composite photocatalyst TNCoPc/BiOBr, using a solvothermal method that involved loading cobalt tetranitro phthalocyanine onto BiOBr. The results of the catalytic performance tests indicated that the composites exhibited the capacity to degrade rhodamine B and tetracycline hydrochloride by 97.75 % and 78.37 %, respectively. Moreover, the composite exhibited good cyclic stability. Subsequent analytical characterization confirmed the formation of a Z-scheme heterojunction, resulting in a synergistic effect. This Z-scheme heterojunction facilitated the capacity of photocatalyst to achieve enhanced light absorption, augmented photogenerated carrier separation efficiency, and augmented redox capacity. Additionally, theoretical calculations were employed to further elucidate the catalytic mechanism and synergistic effects. The results demonstrate that the Co-N4 sites are the active center of the TNCoPc and verify the contribution of nitro substitution to the photogenerated electron transfer mechanism on TNCoPc. Furthermore, a systematic degradation pathway was predicted and deduced based on Fukui indices and liquid chromatography-mass spectrometry data. This study presents a paradigm for the application of composite photocatalysts containing substituted phthalocyanines in the degradation of organic wastewater.

Eco-friendly synthesis of CuO/Bi2O3 nanocomposite for efficient photocatalytic degradation of rhodamine B dye.

Plant-mediated synthesized materials are receiving more attention than conventional ones due to their wide availability, ease of access, simple preparation methods, environmental benign, and possess superior physicochemical properties. In this work, plant extract-mediated CuO, Bi2O3, and CuO/Bi2O3 nanocomposite samples were successfully synthesized using bamboo leaves extract as a capping agent. These materials were utilized for the photodegradation of Rhodamine B (RhB) dye, which served as a model organic dye pollutant. The physicochemical characterization techniques such as XRD, SEM-EDS, FTIR, and DRS-UV-vis spectrophotometry provide insight into the crystal structure, morphology, surface functional groups, and optical properties. These analyses confirm the effective formation of CuO, Bi2O3, and CuO/Bi2O3 materials. Surprisingly, upon calcination at 450°C for 4h, the color of the nanocomposite changed from pale green to gray greenish, providing evidence for the formation of the CuO in CuO/Bi2O3 nanocomposite. The photocatalytic optimization parameters such as pH (4), catalyst load (35mg), irradiation time (180min) and concentration of RhB (10 mg L-1) dye were investigated. By coupling CuO with Bi2O3 nanoparticles resulted in an improved photocatalytic property for the degradation of RhB dye under optimal conditions. As a result, CuO/Bi2O3 nanocomposite exhibited a significantly boosted photocatalytic degradation efficiency (95.6%) compared to pure CuO (40.2%) and Bi2O3 (80.5%) photocatalysts, with good reusability. For comparison purpose, the photocatalytic degradation of RhB dye using selected photocatalyst was evaluated under dark and sunlight systems. This eco-friendly approach holds great potential for synthesis new nanocomposite with modified properties, thereby enabling the practical application of high-efficiency photocatalysts. The plausible mechanism of the electrons and holes transfer was proposed.

Green synthesis of Ag/AgCl nanocomposites derived from Muntingia calabura L. leaves extract: antioxidant properties and catalytic activity in methylene blue degradation

ABSTRACT Ag/AgCl nanocomposites were synthesised using Muntingia calabura L. leaves extract for the first time and were used as antioxidants and catalysts in the degradation of methylene blue (MB). This study aimed to achieve the optimal conditions for synthesising Ag/AgCl nanocomposites using Muntingia calabura L. leaves extract and to examine their antioxidant and photocatalytic activities. Ag/AgCl nanocomposites were confirmed using UV-Vis spectroscopy, Fourier transform-infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and Zeta Potential analysis. Optimising various factors revealed that the optimum synthesis of Ag/AgCl nanocomposites involved mixing 3 mL of 2.5 mm AgNO3 with 7.5 mL of the extract and stirring continuously at 60°C for 100 min. The formed Ag/AgCl nanocomposites displayed mainly spherical shapes with some irregular forms, maintaining an average size of 69.04 nm and remaining stable for 6 months. In vitro studies on antioxidant activity using DPPH indicated that the Ag/AgCl nanocomposites exhibited outstanding free radical scavenging activity, with an IC50 of 62.76 mg/L. In addition, Ag/AgCl nanocomposites showed a strong photodegradation potential for MB, with a degradation percentage of up to 82.12% in 210 min. Hence, the results offer a promising approach for the environmentally friendly synthesis of Ag/AgCl nanocomposites using Muntingia calabura L. leaves extract, with significant applications in antioxidants and photocatalysts.

Application of TiO2 Photocatalyst for Improving Ozone Generation Efficiency

ABSTRACT With a strong oxidizing capability, ozone (O3) is widely used in industry. However, ozone generators on the market are expensive and require a lot of energy to operate, which remains the bottleneck for the wide applications. In this study, a novel and energy-efficient ozone generation system is developed via the combination of black-TiO2 photocatalyst and plasma system. Black-TiO2 catalyst is prepared by calcining commercial TiO2 catalyst at 550 °C under a nitrogen atmosphere to extend the absorption spectrum to visible light range to improve catalytic activity. The experimental results show that ozone generation efficiency can be greatly increased to 415 g O3/kWh via combined black-TiO2 catalyst and plasma with O2 as the feeding gas. This can be attributed to the fact that black-TiO2 catalyst with a smaller energy gap is more efficiently activated to form electron–hole pairs in plasma, which can enhance ozone generation. On the other hand, black-TiO2 catalyst can provide abundant active sites for active O atoms and O2 molecules to promote O3 generation. Black-TiO2 catalyst prepared in this study reveals good stability. Overall, combination of black-TiO2 catalyst with plasma reveals good ozone generation efficiency and has a good potential for practical applications.

Aza-BODIPY-Based Bifunctional Photocatalyst for Red-Light-Driven Asymmetric Hydroxylation of β‑Ketoesters

AbstractA novel bifunctional photocatalyst combining an aza-BODIPY and a chiral oxazoline has been developed. This photocatalyst enables the asymmetric hydroxylation of β‑ketoesters under an oxygen atmosphere and irradiation with 18-W red LEDs. This procedure offers a convenient and potentially general approach to obtain enantioenriched α-hydroxy-β-dicarbonyl products. The results reported in this manuscript demonstrate the promise of this new organic photocatalyst design and will help expand the application of BODIPY-based chiral photocatalysts.

Structural, optical, magnetic, and photocatalytic analysis of exclusive metal aluminates against Congo Red dye under UV light

The exclusive ZnAl2O4 (ZAO), CaAl2O4 (CAO), and MgAl2O4 (MAO) nanocrystallites were prepared by the citrate sol–gel route and further annealed at 600 °C for 2 h. XRD and Rietveld refinement were conducted to explore the crystal structure and to optimize the profile parameters. FTIR confirmed the vibrational peaks of relevant functional groups. The additional stretching and bending IR modes in MAO sample emphasized structural disorders like antisites/native defects. The UV-DRS spectra of these samples analyzed the direct bandgap in 2.76–4.29 eV range. HR-TEM micrographs characterize the well-developed nanosized grains. From VSM data, several magnetic parameters were collected for prepared aluminates and found MAO as best ferromagnetic material with the highest coercive field value (1235 Oe). PL spectra of metal aluminates suggest that the broad peak in violet-blue is attributed to the band edge emission, and finite peaks in higher wavelength regions have appeared due to the large density of surface traps and oxygen vacancies. The photocatalytic mechanism of ZAO, MAO & CAO nanopowder was elucidated on the Congo Red dye (10–70 ppm) solution after exposure to UV light. The highest value of rate constant (k = 0.0118 min−1) suggests that the MAO (0.3 g l−1) sample would be an efficient photocatalyst (98%) under UV light owing to its large surface area (125 m2 g−1) and suitable bandgap. The overall results advocate the practical applicability of aluminate photocatalysts in water treatment, spintronics, and photonics.

Enhancement of Photocatalytic Antimicrobial Performance via Generation and Diffusion of ROS

Review Enhancement of Photocatalytic Antimicrobial Performance via Generation and Diffusion of ROS Xiaojuan Bai 1,2,*, Yihan Cao 1, Bowen Zhu 1, Rujiao Liu 1, Jiaqian Dong 1, and Hua Yang 1 1 Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China 2 Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial and Ministry Co-construction Collaboration Innovation Center, Beijing University of Civil Engineering and Architecture, Beijing 100044, China * Correspondence: baixiaojuan@bucea.edu.cn Received: 8 June 2024; Revised: 8 August 2024; Accepted: 20 August 2024; Published: 20 September 2024 Abstract: The increasing prevalence of antibiotic-resistant infections globally emphasizes the urgent need for effective antimicrobial strategies. Photocatalysts, known for their efficiency, broad-spectrum activity, and environmental benefits, present a promising alternative. With the development of natural solar light driven photocatalysts, the antimicrobial and bactericidal range has been further extended. Photocatalytic materials can be activated by various light wavelengths to generate reactive oxygen species (ROS), which can effectively eliminate a wide range of pathogenic microorganisms including bacteria, fungi, and protozoa. However, the limited optical response range, suboptimal bandgap, and slow electron cycling limit the efficient generation of ROS, resulting in lower sterilization efficiency of photocatalytic antimicrobials. Additionally, the short half-life and limited migration distance of ROS restrict their antimicrobial activity. This review focuses on the process and mechanism of ROS generation in photocatalytic reactions, and highlighting the recent advances in the typical photocatalysts. We also explore strategies to enhance ROS diffusion and utilization, including morphology control, noble metal deposition, doping, co-catalyst loading, vacancy introduction, surface functionalization, and heterojunction construction. These strategies aim to increase the efficiency of ROS generation and prolong their activity, thereby enhancing the overall antimicrobial effectiveness. Thereafter, the review presents state-of-the-art applications of photocatalysts in water purification, medical coatings, and air disinfection. Furthermore, it explores key challenges and opportunities that may drive future innovations and advancements in photocatalytic antimicrobial applications, aiming to develop more effective and sustainable solutions.