Degradation Of Methylene Blue Dye Research Articles

Green Synthesis of Reduced Graphene Oxide Using the Tinospora cordifolia Plant Extract: Exploring Its Potential for Methylene Blue Dye Degradation and Antibacterial Activity.

Graphene has attracted significant attention recently due to its unique mechanical, electrical, thermal, and optical properties. The present study focuses on synthesizing green rGO using the Tinospora cordifolia plant extract by mixing it in a suspension of graphene oxide. The plant extract of T. cordifolia acts as a reducing agent and is cost-effective, renewable, and eco-friendly. Green-synthesized rGO (G-rGO) was characterized using FTIR, HR-SEM, EDX, and HR-XRD analyses. G-rGO consists of nanosheets with an average width of approximately 30 nm. G-rGO has a range of hydrodynamic radius (270-470) nm and an average ζ potential of -29.9 mV. Further, G-rGO was used as a nanoadsorbent for optimal exclusion of methylene blue (MB) dye using the response surface methodology (RSM). Adsorption results confirmed 94.85% MB dye removal with 58.81 mg g-1 adsorption capacity at optimum conditions. The G-rGO's antibacterial activity was also tested against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria, finding the exhibited zone of inhibition of 10, 11, and 15 mm and 10, 13, and 17 mm at 20, 40, and 80 μg mL-1 concentrations of G-rGO, respectively.

Synthesis and characterization of alpha and beta cobalt hydroxide nanostructures for photocatalytic dye degradation and supercapacitor applications

Alpha and beta cobalt hydroxide nanostructures were synthesized by hydrothermal method and characterized using X-ray diffraction and electron microscopy. The turbostatic alpha-Co(OH)2 has large interlayer spacing compared to the beta-Co(OH)2 and is less explored in the literature. Both nanostructures were efficient in degrading methylene blue dye in the presence of visible light. Under identical conditions, the rate constant of photocatalytic dye degradation in the presence of alpha and beta cobalt hydroxide was calculated as 60.22 × 10−3 min−1 and 19.05 × 10−3 min−1, respectively, which is highest when compared to the previous reports. The superior activity of alpha-Co(OH)2 when compared to beta-Co(OH)2 is also demonstrated in this work. Additionally, a Csp value of 137 F/g and 2.4 F/g, respectively, at a current density of 1 A/g, was obtained from the GCD analysis of devices made using alpha-Co(OH)2 and beta-Co(OH)2. A higher cyclic stability and power density were observed for alpha-Co(OH)2 when compared to beta-Co(OH)2. The findings suggest that alpha and beta cobalt hydroxide nanostructures hold promise as effective catalysts for dye degradation and potential materials for high-performance supercapacitors. Further investigations into the unique properties of the relatively superior alpha-Co(OH)2 could lead to advancements in environmental remediation and energy storage technologies.

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

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

Gap type effect on photocatalytic degradation using newly hydrotalcite nanoposite precursor synthesized by hydrothermal method

<p>A novel technique involving hydrothermal synthesis was employed to prepare nanocomposite precursors of lamellar double hydroxide based basic mixed oxides. This method extended ongoing research on iron-impregnated hydrotalcite-supported nanomaterials. The iron-based Fe/MgAl-h nanocomposite was prepared via dry impregnation, introducing a known % by weight of Fe (NO3)3.9H2O metal salt into the hydrothermally synthesized MgAl-h structure. For comparative analysis, the photocatalytic performance of Fe/MgAl-h was compared with the coprecipitation-synthesized Fe/MgAl-c after calcination at 400°C, using various characterization techniques. Structural examination revealed a double-layered hydroxyl structure and the presence of iron oxide phase Fe2O3 in Fe/MgAl-h400. Optical assessments indicated an indirect band gap energy of 1.89 eV for solid Fe/MgAl-h400, which is suitable for visible light absorption. Photocatalytic experiments for methylene blue (MB) dye degradation in aqueous solution were performed under artificial irradiation with a tungsten lamp as the visible light source, mirroring the conditions of Fe/MgAl-c400. Using 50 mg/L MB concentration and 0.5 g/L catalyst quantity, increased MB removal efficiency with time was observed. A comparative study of hydrothermal and coprecipitation synthesis methods showed decreased photodegradation for the hydrothermally prepared solid. Fe/MgAl-h400 and Fe/MgAl-c400 exhibited reaction efficiencies of approximately 46% and 67%, respectively, possibly attributed to their distinct indirect and direct band gap characteristics. Moreover, a wider band gap in a semiconductor material offers several advantages for the degradation of dyes.</p>

Temperature-controlled morphology and enhanced functionalities of hydrothermally synthesized SrFe2O4 nanostructures for multifaceted applications

In this study, we investigate the effect of synthesis temperature on the morphology and properties of spinel strontium ferrite (SrFe2O4) nanostructures, synthesized using a surfactant-free hydrothermal method. We demonstrate that by varying the temperature from 85 °C to 160 °C, we can control the morphology of SrFe2O4, transitioning from nanoribbons to dendritic structures, and finally to hexagonal nanoplatelets. These morphological changes correspond to significant enhancements in both magnetic and photocatalytic performance. The saturation magnetization (Ms) notably increases by up to 70 % at higher synthesis temperatures. Additionally, these nanostructures show improved efficiency in photocatalytic degradation of methylene blue dye, indicating their potential for environmental remediation. The dielectric properties of the various morphologies were also characterized, suggesting applications in electronics and energy storage. This study establishes a clear link between synthesis conditions, resulting structures, and functional performance in SrFe2O4 nanostructures, contributing to the development of advanced materials.

Gas sensing response and photocatalytic efficiency of pH tuned NiV2O6 nanorods

Nickel-vanadium oxide nanocomposite was prepared using the hydrothermal method under different pH values (2, 4, and 6), and its gas sensing response and photocatalytic performance were evaluated. The prepared nanocomposite exhibits an anorthic crystalline structure of NiV2O6. Morphology, size, and optical properties depend on the pH value maintained during the synthesis. The NiV2O6 nanocomposite synthesized under a pH value of 2 has a nanorod structure. The gas sensing response of the NiV2O6 nanocomposite was investigated by measuring the resistance change of the samples in the presence of ammonia and ethanol gases, each with different ppm levels. Photocatalytic degradation efficiency was examined by degrading methylene blue dye under the illumination of halogen light. Scavenger studies were also carried out to identify the radical that plays an important role in the dye degradation process. A maximum degradation of 90 % was found for NiV2O6 nanorods prepared under a pH value of 2.

Deciphering the therapeutic, larvicidal, and chemical pollutant degrading properties of leaves-mediated silver nanoparticles obtained from Alpinia purpurata

The aim of the study was to synthesize silver nanoparticles (AgNPs) from Alpinia purpurata leaves and evaluate their cytotoxic, antimicrobial, antibiofilm, dye degradation, and larvicidal potentials. The synthesized AgNPs were characterized using ultraviolet-visible spectroscopy, Fourier transform infrared, and high-resolution transmission electron microscopy, which confirmed AgNPs synthesis and revealed nanoparticle size (10 to 30 nm) and the presence of silver. Cytotoxicity tests showed IC50 values of 4.59 ± 0.6 µg/mL in A549 cells and 3.48 ± 0.4 µg/mL in PA1 cells, inducing apoptosis and DNA fragmentation. Flow cytometry revealed cell cycle arrest at G0-G1 phase. AgNPs exhibited significant antimicrobial activity, with maximum inhibition zones against K. pneumoniae (23 ± 2 mm) and F. oxysporum (17 ± 2 mm), and minimum inhibitory concentration (MIC) values ranging from 12.5 ± 0.25 to 75 ± 2.5 µg/mL. They also reduced bacterial and fungal biomass and showed antibiofilm effects. Photocatalytic activity degraded methylene blue dye by 88.4 ± 1.4% in 60 minutes. Larvicidal activity resulted in 100% mortality of A. aegypti larvae after 48 hours exposure to AgNPs (10 mg/L), additionally reducing chemical oxygen demand (55.1 ± 2.1% to 63.8 ± 1.5%) and microbial load in wastewater (2.5 to 10 ppm).

Green synthesis of zinc oxide nanoparticles using Albizia procera leaf extract: Degradation of methylene blue dye via Advanced Oxidation Process and Box–Behnken Design

Green synthesis of zinc oxide nanoparticles using Albizia procera leaf extract: Degradation of methylene blue dye via Advanced Oxidation Process and Box–Behnken Design

Facile fabrication of amorphous Al/Fe based metal-organic framework as effective heterogeneous fenton catalyst for environmental remediation.

This study presents a facile preparation and durable amorphous Fe and Al-based MOF nanoplate (AlFe-BTC MOFs) catalyst with notable stability in Fenton reactions. Rigorous characterization using XRD, HR-TEM, and BET confirms the amorphous nature of the synthesized AlFe-BTC MOFs, revealing mesopores (3.4nm diameter), a substantial surface area (232 m2/g), and a pore volume of 0.69cc/g. XPS analysis delineates distinct Al2p and Fe2p binding energy values, signifying specific chemical bonding. FE-SEM elemental mapping elucidates the distinctive distribution of Fe and Al within the framework of AlFe-BTC MOFs. In catalytic activity testing, the amorphous AlFe-BTC MOFs exhibited outstanding performance, achieving complete degradation of Methylene blue (MB) dye and 78% TOC removal over 45min of treatment under mild reaction conditions. The catalyst's durability was assessed, revealing about 75% TOC removal and complete dye decomposition over five successive recycles, with less than 1mg/L of Fe and Al leaching. UV-Vis spectra revealed the destruction of MB dye over multiple recycling studies. Based on this finding, the amorphous AlFe-BTC MOF nanoplates emerge as a promising solution for efficient dye removal from industrial wastewater, underscoring their potential in advanced environmental remediation processes.

Enhanced photocatalytic efficiency of sol-gel derived ZnS-rGO binary nanocomposite

A facile chemical route of synthesis of ZnS-rGO binary nanocomposites is reported here. The efficacy of such nanocomposites as a photocatalyst in degrading the common pollutant dye such as Methylene blue (MB), has been thoroughly investigated and the underlying mechanism is also presented. The standard characterization methods were applied to understand the structure, bonding, morphology, optical and elemental compositions. The results indicated that the ZnS nanoparticles were well dispersed into the rGO nanosheets which due to their 2D sheet structure, served as a favourable template for growth and control of morphology. Increase in rGO amount showed a direct impact on particle size confirmed by XRD and Raman both. The synthesized nanocomposites were utilized as photocatalyst for the degradation of MB dyes under UV irradiation. The optimal combination of ZnS and rGO (in the ratio of 3:2) exhibited enhanced photocatalytic activity. A higher rate constant of 7.01×10−3 min−1, and an approximate degradation efficiency of 75% were obtained after 90 min of degradation. The improvement in photocatalytic activity can be attributed to the enhancement in charge separation, suppressed recombination of electron–hole (e−–h+) carriers, and a possible longer electron lifetime due to the presence of higher amount of rGO. Here, rGO assisted the suppression of charge recombination process in ZnS-rGO and ignited hydroxyl radicals and super-oxide ions which further accelerated the degradation rate of dye. Based on the nature of the dye and its concentration, a significant amount of rGO was needed to maximize the photocatalytic efficiency of ZnS-rGO binary nanocomposites. In addition, the dark current variation with applied bias was explored and it depicted a reduction in dark current with optimized amount of rGO in nanocomposite. The nanocomposites have a strong potential to be utilized in water purification and nano-detectors.

Intensification of organic pollutant degradation under visible light irradiation using ZnO nanostructured photocatalysts doped with praseodymium

Zinc oxide nanostructures doped with praseodymium (ZnO:Pr) at varying Pr content (0.05 % to 1.0 % w/w) were synthesized using the electrospinning-calcination technique. Comprehensive morphological and structural characterizations were conducted through SEM, XRD, and XPS analyses. In addition, diffuse reflectance and photoluminescence spectroscopy measurements were performed to assess the optical properties of materials. The produced photocatalysts (ZnO:Pr) were then employed for the degradation of methylene blue dye and oxytetracycline under visible-light irradiation. ZnO:Pr(0.1 %) demonstrated the best photocatalytic performance against methylene blue showing a pseudo-first-order rate constant of k = 3.630 × 10-2 min−1. Investigation of oxytetracycline photodegradation with ZnO:Pr(0.1 %) revealed a pseudo-second-order rate constant of ks = 1.165 × 10-1 L mg−1 min−1, resulting in a reaction half-life (τ½) of approximately 1 min under optimal conditions. Total organic carbon and mass spectrometry analyses highlighted mineralization and identified the main reaction intermediates, respectively, for the oxytetracycline photodegradation. The photodegradation mechanism of oxytetracycline was proposed by the photocatalytic degradation measurements in the presence of scavengers such as hydroquinone and isopropanol. These nanostructures exhibited robust photocatalytic activity over multiple cycles, demonstrating excellent stability. This study underlines the promising potential of ZnO:Pr(0.1 %) as an efficient photocatalyst able to intensify the photodegradation of organic pollutants.

Preparation and evaluation of magnetic iron oxide-MgCeAl lamellar composite-TiO2 in the photocatalytic degradation of methylene blue dye

A new photocatalyst prepared from ternary lamellar double hydroxides (Mg, Ce, Al) by coprecipitation method and impregnated with TiO2 and magnetic properties was successfully synthesized. Different molar ratios between the trivalent cations were used, varying the proportion of Ce3+ in the Ce3+/(Ce3++Al3+) ratio. The synergistic effect between Ce3+ and TiO2 led to a significant increase in the photocatalytic and kinetic activity of MgCeAl-TiO2 for the photodegradation of the dye Methylene Blue (MB) at a concentration of 20 mg L−1, using UV–visible radiation (filter cut-off for λ > 300 nm). The materials studied were characterized by the techniques of IR Spectroscopy (FT-IR), Raman Spectroscopy, X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), Scanning Electron Microscope (SEM), determination of Zeta Potential and Differential Pulse Voltammetry (DPV). The synthesized photocatalyst that showed the highest efficiency was the one with a composition of Ce3+ = 5 % and Al3+ = 95 %, besides having 5 % of its weight composed of magnetic iron oxide (5Fe/MgCe5Al-TiO2), presenting high photocatalytic activity, completely degrading (∼100 %) the dye in the time of 90 minutes.

Effortless Fabrication of Bi2O3‐Co3O4 Nanocomposite Catalyst: Harnessing Photocatalytic Power for Efficient Cationic Dye Degradation

AbstractA cost‐effective and simple co‐precipitation approach was used to create an efficient photocatalyst Co3O4‐Bi2O3 with identical stoichiometry (1 : 1 of both Co3O4 and Bi2O3). XRD, FTIR, TEM, SEM‐EDS, XPS, UV‐DRS, PL, BET, and TGA were used to characterize the produced material‘s structural and optical properties. The presence of a single phase spinel structure with a distinctive plane (311) was verified by the XRD peak of 2 at 36.9° for Co3O4‐Bi2O3. The SEM pictures revealed clustered consolidated spheres, suggesting particle homogeneity and high interconnectedness. The HR‐TEM and SAED pictures revealed an average crystallite size of 28 nm for the Co3O4‐Bi2O3 heterojunction. The UV‐DRS spectral data demonstrated a 2.1 eV reduction in band gap energy for Co3O4‐Bi2O3 (whereas Co3O4 is 2.4 eV and Bi2O3 is 2.7 eV). Under solar light irradiation, pristine Co3O4, Bi2O3, and Co3O4‐Bi2O3 composites were investigated for photocatalytic degradation of Methylene Blue (MB) and Malachite green (MG) dyes. By adjusting factors such as pH, starting dye concentration, catalyst dosage, and agitation duration, the optimal efficiency was determined. The acquired results showed Co3O4‐Bi2O3 ′s superior activity over both precursors. The composite obtained maximal degradation of 98 % (at pH=11) and 97 % (at pH=9) for MB and MG, respectively. The enhanced photo degradation activity of Co3O4‐Bi2O3 can be due to larger visible light absorption, increased surface area, and decreased h+/e− recombination. The reactive species trapping study was performed to determine the importance of superoxide and hydroxyl radicals during photo degradation. Dye degradation was governed by a pseudo‐first‐order kinetic model. The reusability and stability of Co3O4‐Bi2O3 were confirmed by utilizing the same material for five consecutive runs with both MB and MG dyes. Mass spectra analysis provided insights into the successful degradation of dyes, elucidating intermediate products. The synthesized Co3O4‐Bi2O3 nanocomposite offers unrivalled advantages in terms of structural and optical properties, superior photocatalytic activity, and remarkable stability, making it a promising candidate for efficient dye degradation applications without the formation of toxic by‐products.

Photocatalytic Degradation of Methylene Blue and Methyl Orange Dye by Using the Core-Shell Structure of Fe3O4@ZnS Nanoparticles

A straightforward and highly efficient method was developed for the synthesis of Fe3O4@ZnS core-shell nanoparticles (NPs). These synthesized materials were subsequently utilized for the photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes. The structural characteristics of the prepared sample were meticulously investigated through X-ray diffraction (XRD) and field-effect scanning electron microscopy (FESEM). The XRD analysis confirmed the crystalline phase formation in the Fe3O4 nanoparticles, while a study in the Vibrating Sample Magnetometer (VSM) mode emphasized their strong ferromagnetic behavior. The degradation of dyes was comprehensively studied using UV-Vis analyses, taking into account factors such as pH and initial dye concentration in the decolorization process. The synthesized Fe3O4@ZnS core-shell nanostructure underwent thorough characterization using XRD, UV-Vis spectroscopy, SEM, Fourier-transform infrared spectroscopy (FT-IR), and VSM mode in PPMS. Furthermore, the reusability of the catalyst was explored, yielding promising results. The findings demonstrated the efficient photocatalytic degradation of MB and MO dyes under UV-visible irradiation, achieving significant results within 30-minute intervals.

ZnO heterojunction photocatalysts prepared via facile green synthesis process attaining improved photocatalytic function for degradation of methylene blue dye

ZnO heterojunction photocatalysts prepared via facile green synthesis process attaining improved photocatalytic function for degradation of methylene blue dye

Photocatalytic Degradation of Methylene Blue Dye by Using Different Nanoparticles

Zinc sulfide nanoparticles (NPs) were produced through a straightforward and cost-efficient chemical co-precipitation technique, intended for use in the photocatalytic decomposition of methylene blue (MB) dye, both under ultraviolet and visible light exposure. To evaluate the synthesized nanoparticles, various analytical tools including ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffractometry (XRD) were employed. The XRD analysis confirmed the cubic symmetry of the synthesized NPs. SEM analysis revealed that the nanoparticles tend to aggregate, forming clusters of nanoparticles. TEM analysis illustrated that the ZnS nanoparticles exhibit a spherical morphology with uniform size distribution. Additionally, Fourier-transform infrared (FTIR) analysis exhibited a vibrational peak at 616 cm-1. The degradation of methyl blue was investigated using a UV-Vis spectrophotometer as part of the study.

Boosting photocatalytic activity of β-PbO nanoparticles through metal doping

The current work focuses on the fabrication of pristine and metals (Co, Cu, Ni, Li, and Sn) doped β-PbO phase nanoparticles by cost-effective precipitation method. The properties of the produced nanoparticles were investigated using a variety of characterization techniques. The produced compound was a highly pure β-PbO phase, according to the XRD data. From the UV–vis DRS the obtained bandgap of pristine β-PbO, Co, Cu, Ni, Li, and Sn doped β-PbO was 2.68 eV, 1.88 eV, 2.01 eV, 2.65 eV, 2.64 eV, and 2.70 eV, respectively. The doped samples with the lowest photoluminescence (PL) intensities show the reduced photogenerated electron–hole pair recombination, which increased the photocatalytic activity of β-PbO nanoparticles. The study of the surface morphology by SEM reveals the irregular distribution of the particles. In both pristine and doped nanoparticles, EDX verifies the existence of the expected elements. In comparison to pristine β-PbO, all doped β-PbO nanoparticles have enhanced photocatalytic activity for the degradation of methylene blue (MB) dye under the irradiation of visible light. Among the doped nanoparticles, Cu and Co-doped β-PbO demonstrated particularly high performance. After 80 min of irradiation, Cu and Co-doped β-PbO showed 99.45% and 99.39% degradation rates of MB dye, compared to only 75.13% for pure β-PbO. Hence, the photocatalytic activity of pure β-PbO is boosted through metals doping due to bandgap narrowing, generation of impurity states, increased specific surface area, higher carrier concentration, reduced carriers recombination, the action of dopant ions, and microstructural changes.

Fabrication and synergistically enhanced photocatalytic activity of ternary kaolinite, TiO2, and Al2O3 (K65T30A5) nanocomposite for visible-light-induced degradation of methylene blue and remazol red dye

The ternary photocatalyst ((Al2Si2O5 (OH)4/TiO2/Al2O3) composites (where w/w = 65, 30, and 5 wt%) denoted K65T30A5 were successfully synthesized and examined for their efficiency in removing cationic (Methylene Blue, MB) and anionic (Remazol Red, RR) dye from aqueous medium under visible-light irradiation. A series of nanocomposites with varied wt% of kaolinite, TiO2, and Al2O3 were prepared through sonication followed by calcination at 600 °C. X-ray diffraction (XRD) analysis confirmed the crystallinity of the synthesized materials and established their average crystal size to be 83.87 nm. The morphological structure, composite molecule, and surface properties of the resulting K65T30A5 were characterized using FTIR, FE-SEM, and EDS analyses to confirm the successful fabrication of the nanocomposite. FTIR and EDS elemental mapping analyses confirmed the presence of Al, Si, Ti, and O elements in the nanocomposites. The composites exhibited photocatalytic behaviour across the UV–visible spectra, with values varying from the ultraviolet to the visible region with a sharp increase in reflectance at 510 nm. Near-complete degradation of MB (97.66 %) was achieved within 90 min at pH 9 and a 10 mg/L dye concentration, while RR removal reached 90.66 % within 120 min at pH 3.5 and the same dye concentration under visible light irradiation. The catalyst exhibited robust stability, retaining its efficiency by removing 85.09 % of MB and 80.21 % of RR dye after three reuse cycles. The composite catalyst discussed in this study emerges as a promising material for straightforward fabrication techniques, featuring a high percentage of kaolinite and proving to be a cost-effective solution for large-scale water and wastewater treatment processes.

Two-stage hydrothermal process driven visible light sensitive photocatalytic m-ZnWO4/m-WO3 heterojunction composite materials

The current study reports on the facile two-step hydrothermal synthesis of heterojunction m-ZnWO4/m-WO3 composite powders for visible light sensitive photocatalytic applications. The ZnWO4 particles start crystallizing on the surface of the WO3 powder in the second stage of the reaction in a basic medium. The phases of the composite powders were confirmed using x-ray diffraction analysis. The monoclinic cubic shaped WO3 and rod shaped ZnWO4 morphologies were disclosed from the field emission scanning electron microscope images. Strong interfacial adhesion between ZnWO4 and WO3 was unveiled from the high-resolution transmission electron microscopy study. The optimized composite 5ZW exhibits a calculated bandgap of 2.58 eV, positioning it within the visible light wavelength range (λ = 400–700 nm). Furthermore, there is a notable enhancement in the average lifetime of the electron–hole pair recombination rate, which is extended to 30.3 ns. The composite 5ZW demonstrated 96% methylene blue dye degradation efficiency within 420 min under visible light irradiation at pH 12. Due to the optimal phase fraction and strong interfacial adhesion between ZnWO4 and WO3, the heterojunction scheme seemed to be highly efficient in the 5ZW composite. Hence, it is believed that a two-step hydrothermal method can be a proficient route to prepare heterojunction composites m-ZnWO4/m-WO3 in alkali conditions with visible light active photodegradation efficiency.

Improving Photocatalytic Performance through Incorporation of Various Cations in A-site of Double Perovskite Material (Cs0.50MA0.50)2SnI6 for Degradation of Methylene Blue Dye Pollutant under Visible Light Irradiation

In this article, undoped double perovskite materials like caesium tin iodide (Cs2SnI6), methyl ammonium tin iodide [MA2SnI6: MA denotes CH3NH3+] and mixed double perovskite material [(Cs0.50MA0.50)2SnI6] were synthesized using a wet chemical methodology. The crystal structure confirmation, optical properties, thermal properties, surface morphology and presence of elemental composition of the prepared samples using XRD, UV, TGA and FESEM-EDAX analyses were thoroughly investigated. The synthesized materials were employed as photocatalysts to degrade methylene blue dye within 120 min under visible light. An increase in the optical properties of the synthesized double perovskite materials was confirmed by ultraviolet (UV) analysis, which showed that the introduction of various cations into the perovskite material at the A-site shifted the photoluminescence (PL) emission peak to the red. TGA results demonstrated that (Cs0.50MA0.50)2SnI6 has greater thermal stability, which was confirmed by the presence of 43% of sample despite the temperature reaching almost 870 ºC. Doped double perovskite material (Cs0.50MA0.50)2SnI6 exhibited increased photocatalytic activity, with methylene blue dye degradation efficiency attaining 89% after 120 min of visible light irradiation, which is greater than pure double perovskite materials. The photocatalytic degradation of methylene blue dye is mostly facilitated by hydroxyl radicals and holes, according to a radical trapping experiment that we conducted by employing different scavengers. The results of the current work showed that doped double perovskite materials [(Cs0.50MA0.50)2SnI6] exhibit high thermal stability as well as higher photocatalytic activity than pure double perovskite materials. A possible photocatalytic reaction process is also diagrammatically using the band positions of double perovskite materials found using Mott-Schottky plots , which confirms that the synthesized double perovskite material has an N-type semiconductor nature.