Dye Degradation Efficiency Research Articles

Membrane-free Electrolysis Production of Hydrogen Peroxide on Low-Cost Metal-Free Electrocatalysts for Dye Degradation.

The efficient production of hydrogen peroxide (H2O2) solution was achieved by combining cathodic two-electron oxygen reduction (2e- ORR) and anodic two-electron water oxidation (2e- WOR) in two half-reaction cells. h-BN loaded on carbon fibers (h-BN@C) is prepared and employed as an anode material to catalyze 2e- WOR, while sulfonated commercial BP-2000 carbons (BP-2000-SO3H) were prepared as the cathode materials for 2e- ORR. In a 2 M KHCO3 solution, an overall Faradaic efficiency of 97% and a total H2O2 production rate of 1872 mmol g-1 h-1 over metal-free electrodes were accomplished in a membrane-free flow cell. The dilute H2O2 solution could be directly used to degrade cationic Rhodamine B or methyl orange and anionic methylene blue dyes in water. This work proved low-cost production of dilute H2O2 solution in simple membrane-free flow cells with single electrolyte and on-site utilization for efficient dye degradation.

Visible-light photocatalytic performance of SrTiO3 nanoparticles modified with cobalt.

In this article, an experimental study on the photocatalytic performance of SrTi1-yCoyO3 nanoparticles (with y = 0.0, 0.03, 0.06, and 0.09) synthesized by the Pechini-type sol-gel method is presented. The crystalline structure analysis revealed that all the samples exhibited the cubic perovskite phase of SrTiO3. In particular, the SrTi0.91Co0.09O3 sample was found to consist of rough spherical-like particles with an average size of 26 ± 0.5 nm. Cobalt ions with 2+ and 3+ oxidation states are responsible for modifying the electronic band structure of the semiconductor and a narrowing of optical band gap from 3.1 to 1.08 eV. The resulting Co-doped SrTiO3 nanoparticles exhibited photocatalytic activity under visible light due to their enhanced light absorption, effective charge transport and effective surface chemisorption. In particular, the SrTi0.91Co0.09O3 sample exhibited the highest photocatalytic activity with 91% degradation efficiency of methylene blue dye within 120 min of simulated solar irradiation.

Synthesis of zinc oxide semiconductor nanoparticles using natural extract: a systematic evaluation of cationic dye photodegradation influenced by extract concentration, catalyst dose, and pH.

This work obtained zinc oxide nanoparticles (ZnO NPs) using organic components extracted from Waltheria americana at different concentrations. ZnO materials were subsequently applied in the photodegradation of two cationic dyes, Rhodamine B (RB) and methylene blue (MB), at different doses of catalyst and pH. The crystallinity and hexagonal Wurtzite structure of ZnO were established through XRD analysis. The Zn-O bond in the ZnO NPs was confirmed in the FTIR, with the characteristic signals observed in the fingerprint region at ~ 400cm-1. SEM and TEM revealed the formation of quasi-spherical particles with an average size ranging from 2 to 12nm, depending on extract concentrations during synthesis. UV-Vis studies indicated the optical bandgap of ZnO, with values below 3eV, also dependent on extract concentration. PL analysis revealed the recombination of free excitons and defects in ZnO. Photocatalytic studies of ZnO materials demonstrated excellent degradation efficiency of RB and MB dyes, which was influenced by the extract concentration of NPs, while the degradation of MB was enhanced with a 1:1 dye-to-catalyst ratio under acidic conditions. In contrast, due to RB more complex structure, an increased ratio of 1:1 to 1:3 and acidic pH conditions improved its degradation. Green-synthesized ZnO NPs using photocatalysis techniques exhibit significant potential as eco-friendly alternatives for removing contaminants from water.

Optimisation, Synthesis, and Characterisation of ZnO Nanoparticles Using Leonotis ocymifolia (L. ocymifolia) Leaf Extracts for Antibacterial and Photodegradation Applications

This work presents a green synthesis route, which utilises extracts from an indigenous plant in South Africa, eastern and southern Africa that is understudied and underutilised, for preparing zinc oxide nanoparticles (ZnO NPs). This study involved optimisation of the green synthesis method using Leonotis ocymifolia (L.O.) extracts and performing comparative studies on the effects of using different zinc (Zn) salt precursors; zinc sulphate heptahydrate (Z001) and zinc acetate dihydrate (Z002) to synthesise the ZnO NPs. The comparative studies also compared the L.O-mediated ZnO NPs and chemical-mediated ZnO NPs (Z003). The as-prepared ZnO NPs were tested for their effectiveness in the photodegradation of methylene blue (MB) dye. Furthermore, antibacterial studies were conducted using the agar well diffusion method on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. The structural, morphological, and optical characteristics of the synthesised ZnO NPs were analysed using XRD, FTIR, SEM, EDS, DRS, and BET techniques. The XRD results indicated that the L.O-mediated ZnO NPs had smaller crystallite sizes (18.24–19.32 nm) than their chemically synthesised counterparts (21.50 nm). FTIR confirmed the presence of biomolecules on the surface of the L.O-mediated NPs, and DRS analysis revealed bandgap energies between 3.07 and 3.18 eV. The EDS results confirmed the chemical composition of the synthesised ZnO NPs, which were made up of Zn and O atoms. Photocatalytic studies demonstrated that the L.O-mediated ZnO NPs (Z001) exhibited a superior degradation efficiency of the MB dye (89.81%) compared to chemically synthesised ZnO NPs (56.13%) under ultraviolet (UV) light for 240 min. Antibacterial tests showed that L.O-mediated ZnO NPs were more effective against S. aureus than E. coli. The enhanced photocatalytic and antibacterial properties of L.O-mediated ZnO NPs highlight their potential for environmental remediation and antimicrobial applications, thus supporting sustainable development goals.

Physical and enhanced photocatalytic MO dye degradation behaviour of Zn doped β-Ga2O3 microrods

This work explored the effects of Zn doping on the structural, micrographic, optical and photocatalytic behaviour of gallium oxide (β-Ga2O3) microrods. The X-ray diffractogram (XRD) and Raman spectral analyses confirmed the monoclinic structure of β-Ga2O3, with a shift to lower angles in the XRD pattern indicating Zn incorporation into the Ga2O3 lattice. The Scanning electron microscopy (SEM) images revealed a rod-like shape, with the diameter decreasing from 604 nm to 573 nm with Zn doping. Further analysis using TEM, HR-TEM, SAED, EDX, and elemental mapping confirmed the shape, crystallinity, crystal structure, and elemental distribution. The interplanar spacings were measured as 0.4 and 0.2 nm, corresponding to the (002) and (−311) planes of β-Ga2O3. UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS) showed a slight shift in the absorption edge, while photoluminescence (PL) analysis demonstrated strong UV and weak visible light emission. Photocatalytic results revealed a high efficiency of dye degradation,(i.e) 98 % (20 ppm) and 89 % (30 ppm) against methyl orange (MO) dye aqueous solution over 150 min, with a rate constant of 0.02/min and 0.01/min, respectively for 1.5 wt% Zn doping. This suggests that the Zn-doped material holds promise as a photocatalyst for wastewater treatment applications.

Designing an eco-friendly Co/MnS/S-g-C3N4 nanocomposites: revolutionizing photocatalytic dye degradation and antibacterial efficiency

Designing an eco-friendly Co/MnS/S-g-C3N4 nanocomposites: revolutionizing photocatalytic dye degradation and antibacterial efficiency

Low cost fabrication of continuous flow optofluidic microreactor for efficient dye degradation using graphene QDs@MOF (Ti) photocatalyst

The optofluidic microreactor, a convergence of optics and microfluidics, offers advanced functionalities that can be pivotal in the rapid assessment of nanocatalysts for tackling environmental contamination issues. This article presents an efficient approach for degrading Methylene blue (MB) dye, commonly used in the textile industry, within a cost-effective polydimethylsiloxane (PDMS) based continuous flow optofluidic microreactor. This microreactor combines graphene quantum dots (QDs) and NH2-MIL-125 (MOF(Ti)) as a highly effective photocatalyst coating within its microchannels. By directly incorporating graphene QDs@MOF(Ti) into the microchannels, the photocatalytic medium is brought into close proximity with the flowing MB dye solutions, thereby reducing the necessary interaction time and enhancing purification efficiency. Furthermore, the findings demonstrate an impressive degradation efficiency of ∼99% for MB dye at a flow rate of 50 μL min−1 under visible light irradiation, achieved in a single pass. Additionally, the microfluidic reactor exhibits prolonged stability of the photocatalyst, enabling its reuse without significant efficiency loss. In addition, a comparative analysis highlights the advantages of microreactor-based photocatalysis over traditional methods. These advancements in the features of the graphene QDs@MOF(Ti) nanocomposite substantiate their demonstrated superiority in degradation efficiency.

Fe/Mo bimetallic synergy system for ultra-highly efficient degradation of Rhodamine B

The traditional Fenton process, which depends on the use of Fe2+/H2O2, is constrained by the consumption of ferrous ions and the requirement for large amounts of H2O2. However, the assembly of bimetallic synergy systems with adjustable valence metal cations and enhanced dispersion of active sites has been evidenced to address these limitations. In this work, the Fe/Mo bimetallic synergy system in FexMo-CN materials is explored, utilized for the degradation of dyes with the assistance of H2O2. The cooperative effect of Fe/Mo bimetallic and the highly dispersed FeMoO4 as active sites make materials to achieve ultra-highly efficient degradation of dyes, approximately 100 % Rhodamine B (RhB) degradation within 6 min. And the corresponding degradation rate constant is 1.3471 min−1. Additionally, FexMo-CN materials exhibit excellent stability and versatility in solutions containing various cations, anions, or other dyes. Quenching experiments and EPR tests demonstrate that singlet oxygen (1O2) serves as the main reactive oxygen species (ROS) to degrade RhB. And the mechanism of generated 1O2 is revealed. The degradation path and mechanism of RhB are analyzed and the toxicology of intermediate products are calculated in detail. This work presents a novel approach for enhancing efficiency in Fenton-like reactions within the field of environmental remediation.

Visible Light Active 0.95KNbO3‐0.05Ba(Nb1/2Sc1/2)O3 Ferroelectric for Enhanced Photocatalytic Activity

AbstractThis study reports a visible light active Ba/Sc co‐doped potassium niobate (KNbO3) ferroelectric material for enhanced photocatalytic applications. Through 5% Ba and Sc co‐doping in KNbO3 (i.e., 0.95KNbO3‐0.05Ba(Nb1/2Sc1/2)O3), the electronic band gap (Eg) is narrowed down to the visible range of the solar spectrum. The prepared samples are systematically examined by using X‐ray diffraction and Raman spectroscopy, which confirms the successful incorporation of Ba and Sc ions into the KNbO3 lattice. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis reveal particle morphology and chemical homogeneity of prepared samples. The UV–vis spectroscopy and ferroelectric PE‐loop demonstrate enhanced optical absorption compared to host KNbO3 while retaining ferroelectric behavior. The photoelectrochemical (PEC) measurements under visible light irradiation demonstrate a notable enhancement in the photocurrent for 0.95KNbO3‐0.05Ba(Nb1/2Sc1/2)O3 (hereafter denoted by 5KBSNO) compared to undoped KNbO3. Additionally, the 5KBSNO sample displays enhanced RhB dye degradation efficiency, reaching ≈50% compared to parent KNbO3 (≈30%) under light irradiation. First‐principles density functional theory (DFT) calculations are employed to understand the mechanism responsible for the reduced band gap. This study presents a promising material for developing advanced ferroelectric photocatalysts with tailored band structures for efficient solar energy harvesting for energy conversion and contamination remediation applications.

Eco-Friendly Photocatalytic Treatment of Dyes with Ag Nanoparticles Obtained through Sustainable Process Involving Spirulina platensis

The development of efficient photocatalysts is crucial in addressing water pollution concerns, specifically in the removal of organic dyes from wastewater. In this context, the use of silver nanoparticles (Ag NPs) might represent a method to achieve high dye degradation efficiencies. On the other hand, the classical Ag NP production process involves several reactants and operating conditions, which make it poorly sustainable. In the present work, Ag NPs were synthesized according to a new sustainable process involving the use of natural extracts of Spirulina platensis and milder operating conditions. The material was also calcined to determine the influence of organic content on the properties of Ag NPs. The X-ray diffraction (XRD) analysis displayed the AgCl and Ag phases with a crystalline size of 11.79 nm before calcination. After calcination, only the Ag phase was present with an increased crystalline size of 24.60 nm. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the capping role of the metabolites from the extract. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the spherical or quasi-spherical morphologies with agglomeration due to the calcination. Energy-dispersive X-ray spectroscopy (EDX) and Thermogravimetric (TGA) analyses further confirmed the involvement of metabolites in the synthesis of Ag NPs. The optical changes in the products were observed in a UV-Vis analysis. The Ag NPs were tested for their photocatalytic activity against the laboratory dye brilliant blue r in visible light in various conditions. The highest degradation efficiency of 81.9%, with a kapp value of 0.00595 min−1, was observed in alkaline medium after 90 min of light irradiation.

Rapid Degradation Of Dye Effluents With A SnS Catalyst: A Sustainable Approach Using Natural Light Under Ambient Conditions.

Dye degradation presents a persistent challenge in addressing water pollution. While several methods, including adsorption, biodegradation, and advanced oxidation processes, have been extensively explored, photocatalysis remains one of the most effective techniques. Conventional photocatalytic dye degradation processes often rely on expensive light sources and are time-intensive. Herein, we synthesized a SnS catalyst using solvated metal atom dispersion (SMAD) method, using Sn foil and sulfur powder. The catalyst exhibited remarkable performance, achieving complete degradation of methylene blue within 2 minutes under ambient room light, without the need for any external light source. Similar degradation efficiency was achieved for methyl orange. To evaluate the role of light for the degradation, control experiments were conducted in the dark using methylene blue as a model dye. Although the degradation rate was slightly reduced, the catalyst still facilitated dye degradation in the absence of light. Additionally, the catalytic performance was tested with four other dyes under natural light, all of which yielded promising results, demonstrating the versatility and effectiveness of the SnS catalyst in dye degradation. This work highlights the potential of the SnS catalyst for efficient and rapid dye degradation under both light and dark conditions, offering an energy-efficient solution for wastewater treatment.

Molten-salt-chemistry-assisted synthesis of heterostructured g-C3N4/BiOI nanocomposites with enhanced sunlight absorption properties for efficient solar-to-chemical energy conversion

The g-C3N4 nanosheets coupled BiOI (g-C3N4/BiOI) nanocomposites with unique heterojunction structure and excellent wide-spectrum sunlight absorption properties have been developed via molten-salt-chemistry-assisted strategy. The heterostructured g-C3N4/BiOI shows enhanced solar to the thermal effect, improved electron mobility and carrier lifetime for efficient photocatalytic dye degradation. The engineered g-C3N4/BiOI catalyst exhibits outstanding photocatalytic activity for methyl orange (MO) removal with 100 % degradation conversion and excellent stability under solar light irradiation, which is respectively 2.69 and 1.27 times higher than those of g-C3N4 and BiOI counterparts. The broad scope toward other dyes degraded by g-C3N4/BiOI and the generality of the molten-salt-chemistry-assisted strategy for synthesizing g-C3N4/BiOCl and g-C3N4/BiOBr with considerable photodegradation efficiency are proved. The analysis of kinetic behaviors, electron spin resonance, and nanosecond transient absorption spectra for structure-activity relationship, key intermediate of •O2− species, and excited state lifetime of g-C3N4/BiOI heterojunction material in the photocatalytic MO degradation processes are also demonstrated.

Photocatalytic activity of molybdenum-doped LOS- zeolite for efficient dye degradation and hydrogen production

This research investigates the synthesis and application of Losod-zeolite (LOS-Z), a crystalline hydrated sodium aluminosilicate (Na12Al12Si12O48.xH2O) as a potential photocatalyst for dye degradation and H2 production from dye-degraded water. The photocatalytic properties are enhanced by impregnating molybdenum (Mo) into LOS-Z (Mo@LOS-Z). XRD, FTIR, SEM, EDX, and elemental mapping were used to study the physicochemical properties of synthesized materials while UV–vis and PL were employed to explore the optoelectronic properties. The photocatalytic activities for dye degradation and H2 production were evaluated using methylene blue (MB) under visible light irradiation. An enhancement in the efficiency of dye degradation (56%–82%) and H2 production rate was demonstrated due to the competitive photocatalytic performance of 10% Mo@LOS-Z compared to the pristine LOS-Z and CFA-BFA blend. It exhibited 2.5 times higher (∼1200 μmol g−1h−1) H2 production than the LOS-Z (∼480 μmol g−1h−1) due to the synergistic effects of narrowed band gap and recombination rate. This study could pave the way forward into the synthesis of waste-derived photocatalysts for efficient dye degradation and H2 production.

Photo-Fenton-like activity of Fe/ZnO structure applied as a heterogeneous catalyst for the methylene blue dye removal in aqueous matrices

This work developed efficient heterogeneous catalysts for the methylene blue (MB) dye degradation under photo-Fenton-like conditions. The material was modified to incorporate Fe(III) into ZnO, creating Fe/ZnO strucuture, and applied as heterogeneous catalysts at various pH levels. SEM analysis revealed an agglomerated and plate-like morphology of the synthesized catalysts. The enhanced structure facilitated a removal efficiency of 96.2% for MB dye when employing the photo-Fenton-based process using 5.0% Fe/ZnO catalyst. The high removal efficiency is attributed to the synergy between ≡Fe(III) and ≡Zn(II), which promotes the generation of photoradical species through the Fenton effect. Real water matrices served as a source of MB dye contamination, exhibiting minimal interference and achieving ∼100 % of removal. Scavenger studies indicate that •OH and e⁻ are the primary contributors to the high MB dye degradation efficiency. Additionally, the by-products formed after photo-Fenton process exhibit minimal toxicity towards Lactuca sativa L. No Fe(II) ions were leached at the end of the process. Eight cycles of degradation did not cause significant spectral changes in the FTIR analysis, as well as in the XRD patterns, indicating the material efficient and stable structure.

Studies of pure TiO2 and CdSe doped TiO2 nanocomposites from structural, optical, electrochemical, and photocatalytic perspectives

A low temperature hydrothermal method is employed in this study to synthesize CdSe doped TiO2 nanocomposites. Further characterization and studies of the synthesized particles were carried out. As part of this study, the sample was examined by X-ray diffraction to determine its structure, crystallite size, strain, and crystallinity. Molecules were analyzed by energy dispersive X-ray spectroscopy to determine their chemical composition. By using fourier transform infrared spectroscopy spectroscopy, we were able to observe the presence of functional groups as well as the types of bonds. By analyzing the scanning electron microscopy spectra, we were able to determine the particle size while by analyzing the photoluminescence spectra, we could determine the bandgap energy. To determine the nature of materials and their effective photocatalytic behavior, optical bandgap energies were observed in the ultra-violet visible spectrum of synthesized particles. For determining the charge transfer mechanism and specific capacitance, electrochemical studies were conducted using electrochemical impedance spectroscopy and cyclic voltammetry analysis. The degradation of malachite green and Rhodamine-B dyes with CdSe doped TiO2 nanocomposites in the visible region was studied for photocatalytic activity, degradation efficiency, and rate constant. According to the results, doped nanoparticles increased the efficiency of RhB dye degradation by ~ 4% and MG dye degradation by ~ 20% over pure nanoparticles.

A Spin‐Polarized Electron‐Induced MXene‐KBi0.9Co0.1Fe2O5 Photocatalyst for Enhanced Dye Degradation

In photocatalysts aimed to degrade environmental pollutants, photons are generally used as primary stimuli to generate electron–hole pairs to target the chemical bonds to disintegrate. Recently, electron spin has been reported as an essential degree of freedom to improve the performance of photocatalysts. In this work, spin‐polarized electrons and holes are introduced into a brownmillerite KBi0.9Co0.1Fe2O5 semiconductor and a two‐dimensional (2D) MXene composite system by application of an external magnetic field. The spin polarization properties are monitored by measuring the magnetoresistance effect of the MXene‐KBCFO device, which is related to the carrier transfer efficiency. Remarkably, the photocatalytic performance of MXene‐KBCFO is significantly enhanced by the simultaneous application of an external magnetic field and illumination due to the increased number of spin‐polarized photoexcited carriers caused by the synergy effect of the 2D MXene heterostructure together with the ferromagnetic spin ordering. This results in increased reaction hotspots, effective built‐in electric field, extended carrier lifetime, and reduced charge recombination owing to parallel alignment of electron spin orientation. The results show that the efficiency and stability of photocatalytic dye degradation can be effectively enhanced by manipulating the spin‐polarized electrons in the MXene‐based oxide‐perovskite heterostructure photocatalyst.

Micro-nano bubbles in action: AC/TiO2 hybrid photocatalysts for efficient organic pollutant degradation and antibacterial activity

Developing highly active and sustainable photocatalysts is crucial for environmental remediation. This work focuses on the enhanced photocatalytic degradation efficiency of synthetic dyes using TiO2-coated AC hybrid photocatalysts under MNB aeration. The TiO2-coated AC hybrid photocatalyst (HP) was synthesized via a sol-gel method and characterized using XRD, FTIR, SEM, EDS, HR-TEM, and DRS. The study investigated the photocatalytic degradation of three dyes indigo carmine (IC), reactive black 5 (RB5), and methylene blue (MB) in wastewater, with initial dye concentrations ranging from 10 to 100 μM. Under UVA irradiation, the hybrid photocatalyst with MNB aeration (HP + UVA + MNB) achieved the highest degradation efficiencies of 69.09%, 60.06%, and 55.19% for IC, MB, and RB5, respectively. Further analysis showed that the chromophores and complex structures of these dyes were broken into intermediate products. The Langmuir-Hinshelwood kinetic model was used to describe the reaction mechanisms. The HP + UVA + MNB system demonstrated superior photocatalytic degradation activity, making it suitable for operational and environmental applications in dye wastewater treatment. Additionally, the antibacterial properties of AC and HP were tested at 100 μg/mL, showing effectiveness against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli.

Copper-PANI-graphite HB2 composite for eco-friendly efficient degradation of textile dyes: Advancements in wastewater treatment enhanced by solar radiation

This research aimed to assess the potential of Cu50PANI@UG composite for sunlight drive photocatalytic dye degradation, targeting specifically Thymol Blue (TB) and Black NT (BNT) dyes and their mixture (DM). The Cu50PANI@UG composite was successfully synthesized via electropolymerization in acetonitrile/sulfuric acid mixture under atmospheric conditions. Photocatalytic experiments were conducted by exposing aqueous dye solutions to sunlight. N,N-dimethyl-p-nitrosoaniline (RNO) served as a molecular probe for detecting hydroxyl radicals (•OH). Additionally, experiments capturing free radicals were performed to identify active components, with a concomitant proposal of plausible degradation reaction mechanism for the Photo-Fenton-Like degradation into the Cu50PANI@UG composite + H2O2 + hv reaction system. Various operating parameters affecting dye degradation were evaluated, including catalyst dosage (from 0.27 to 0.67 g L−1), H2O2 concentration (from 16 to 64 mM), pH (from 3.0 to 9.0), and dye concentration (from 25 to 100 mg L−1). Optimization of key parameters such as pH, catalyst dosage, and H2O2 concentration was conducted. The highest degradation efficiency, ca. 100% of DM dye, was achieved within 35 min under optimized conditions, using Cu50PANI@UG composite as a catalytic precursor. These conditions were determined as follows: Catalyst dosage = 0.67 g L−1, pH = 3.0–6.0, H2O2 = 32–64 mM, and irradiation time of 35 min. The degradation percentage under the Response Surface Methodology (RSM) was utilized as a statistical tool to correlate influential parameters. Four consecutive reusability trials were performed to assess catalyst stability.

Green-synthesized BiFeO3 nanoparticles for efficient photocatalytic degradation of organic dyes, antibiotic and catalytic reduction of 4-nitrophenol

Green-synthesized nanoparticles have recently emerged as promising catalysts for the removal of toxic dyes from water bodies. In this article, Bismuth ferrite (BiFeO3) nanoparticles were synthesized by a simple and low-cost method using Couroupita guianensis plant leaf extract. The particles were used as photocatalysts for degrading RhB, MO dyes, and TC antibiotics, as well as for reducing toxic 4-NP to useful 4-AP. The synthesized nanoparticles were characterized using several state-of-the-art tools. The formation of perovskite structure and the presence of biomolecules on the surface of BiFeO3 nanoparticles was confirmed by FTIR analysis. Raman spectrum revealed a rhombohedral structure of BiFeO3 nanoparticles, corroborating the XRD analysis. FESEM micrograph demonstrated irregularly shaped agglomerated nanoparticles. The average hydrodynamic diameter was estimated to be 51 nm using the DLS technique. The optical energy bandgap of the bismuth ferrite was estimated using Tauc’s relation for direct bandgap semiconductors. SQUID measurements revealed that these nanoparticles exhibit a weak ferromagnetic ordering. Furthermore, these nanomaterials degraded the cationic and anionic dyes effectively because of the formation of hydroxyl radicals, confirmed by the scavenger test. The photocatalytic degradation pathway of RhB dye was investigated through LC-MS analysis, and the intermediate degradation products were identified. The prepared material also exhibited excellent catalytic efficiency in a short duration of time. This study proclaims that these nanoparticles can be used as potential catalysts for the purification of water.

Biosynthesized Gold Nanocatalyst Using Ginkgo Biloba Fruit Extract for Efficient Catalytic Degradation of Azo Dyes

AbstractGold nanoparticles (AuNPs) are increasingly utilized for their opto‐electrical properties in various high‐tech applications, including electronic conductors, sensory probes, and drug delivery systems. However, their widespread application is limited by their tendency to agglomerate. In this study, AuNPs were synthesized using a cleaner approach and stabilized with Ginkgo biloba fruit extract (GBFE), avoiding toxic agents. The synthesis parameters were optimized using a one‐variable‐at‐a‐time technique, resulting in primarily spherical/oval particles with high crystallinity (d‐spacing=0.204–0.231 nm), nano‐scale size (10.3±2.9 nm), and remarkable stability (zeta potential of −20.06 mV). The synthesis mechanism involved a redox reaction between phytochemicals and metal cations, leading to the generation and stabilization of AuNPs. The AuNPs exhibited catalytic activity in reducing two azo compounds, i. e., reactive yellow 179 (RY179) and reactive orange 5 (RO5) as the models, achieving a degradation rate of over 98 % within 15 minutes. The kinetic rate constants (k) for RY179 and RO5 were calculated as 0.2771 min−1 and 0.2297 min−1, respectively. The AuNPs alone could not degrade azo dyes since NaBH4 was required to provide a source of electrons for transferring to the dye molecules. This eco‐friendly synthesis method demonstrates the potential for synthesizing catalytically active AuNPs for various industrial applications, including wastewater treatment.