Ultraviolet-visible Diffuse Reflectance Spectroscopy Research Articles

Unravelling the interaction of ethyl cinnamate in 2-hydroxypropyl and methyl-β-cyclodextrin by spectroscopic and theoretical evaluation for enhanced antibacterial activities

Essential oil components are the most common agents used to inhibit pathogens. Ethyl cinnamate (ECIN) is a hydrophobic essential oil component with well-known antibacterial properties but is poorly soluble in water, which limits its applications. In this study, inclusion complexes (ICs) were prepared by encapsulating ECIN in β-cyclodextrin (βCD), 2-hydroxypropyl-βCD, or methyl-βCD using an ultrasonication method to enhance water solubility and thermal and antibacterial properties. UV–Vis absorption and fluorescence spectral results indicated strong non-covalent interactions between ECIN and βCD derivatives in aqueous solution, and double reciprocal profiles revealed a guest:host stoichiometry of 1:1. Fourier-transform infrared and proton nuclear magnetic resonance spectroscopy investigations revealed that the phenyl ring of ECIN is located deeply in the CD nanocavities. X-ray diffraction, ultraviolet–visible diffuse reflectance spectroscopy, photoluminescence, and field emission scanning electron microscopy were performed to obtain crystalline, optical, and morphological information on solid ECIN-CDs. Thermogravimetric/differential thermal studies confirmed the improved stability of ECIN in solid CD-ICs by detecting an increase in the degradation temperature of ECIN from 50–140 °C to 310–410 °C. Further, the geometrical and frontier molecular orbital structures of the ECIN-CDs were theoretically evaluated using parametric method-3. Finally, antibacterial assays conducted against the foodborne pathogens Staphylococcus aureus and Escherichia coli revealed that encapsulated ECIN had a greater inhibitory effect, which suggested the devised nanocarriers promote the solubilization of essential oil components in aqueous solutions.

Annealing construction of in situ heterojunction for photocatalytic degradation of bisphenol A

Here, we report the synthesis of bismuth oxyiodide (BiOI) photocatalysts with oxygen vacancy defects by a one-pot solvothermal method followed by annealing in a nitrogen atmosphere. This method allows the oxygen vacancy concentration to be tuned and provides new insights into defect engineering of photocatalytic materials. We found that the Bi2O3/BiOI heterojunction formed after annealing at 400°C significantly improves the photocatalytic performance, which provides a new strategy for the optimal design of structures for efficient photocatalysts. Using a combination of characterization techniques such as X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), as well as density-functional theory (DFT) calculations, we have elucidated the photocatalytic mechanism of the Bi2O3/BiOI heterojunctions, highlighting their role in facilitating the photogenerated charge-carrier separation and transfer. The optimized A-B40 samples exhibited photocatalytic degradation efficiencies of up to 99.7% for bisphenol A (BPA), highlighting their potential for remediation of environmental pollutants. This study presents a method for the preparation of high-performance BiOI-based photocatalysts, which offers valuable theoretical and experimental prospects for the development of eco-friendly photocatalytic materials.

Enhanced Fenton-Photocatalytic Degradation of Rhodamine B over Cobalt Ferrite Nanoparticles Synthesized by a Polyvinylpyrrolidone-Assisted Grinding Method.

A simple grinding method using polyvinylpyrrolidone (PVP) as a capping agent is introduced to synthesize CoFe2O4 nanoparticles. The effects of calcination temperature (ranging from 450 to 850 °C) on the structural, morphological, physical, and optical properties of the materials are investigated using various techniques, including thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), N2 adsorption isotherm, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), and vibrating sample magnetometry (VSM). The presence of PVP significantly suppresses the agglomeration of the materials, resulting in a nanocrystalline size of 18 nm for a sample calcined at 650 °C, which is approximately 38% smaller than that of the sample synthesized without PVP. Among the materials studied, the sample calcined at 650 °C exhibits unique properties, including optimal average pore size, specific surface area, and band gap energy, contributing to its superior photocatalytic degradation of rhodamine B via the Fenton reaction. Systematic experiments are performed to investigate the effects of pH, catalyst dosage, dye, and H2O2 concentrations and competitive anions on the rhodamine B degradation. Additionally, the Fenton photodegradation of RhB on CoFe2O4 is well-fitted to the first-order kinetic model. The redox pairs of Co(III)/Co(II) and Fe(III)/Fe(II) in the CoFe2O4 spinel structure might facilitate the formation of Fenton radicals, contributing to the decomposition of RhB through a proposed four-step mechanism. Notably, the material exhibits a strong magnetic response and maintains its excellent performance over five cycles, demonstrating the high potential for reusability as a photocatalyst.

Synthesis and photocatalytic activity of Ag/AgCl for removal of BTX vapors under visible light: modeling by ANN

Abstract Among volatile organic compounds, benzene, toluene, and xylene (BTX) are the most harmful organic compounds and the removal of these harmful compounds is mandatory. In the current study, Ag/AgCl composite was successfully synthesized via deposition–precipitation along with the photoreduction method. The scanning electron microscopy, x-ray powder diffraction, photoluminescence spectroscopy, Fourier transform infrared spectra, and ultraviolet-visible diffuse reflectance spectroscopy were employed to characterize the synthesized products. The photocatalytic property of the products was investigated by evaluating on photodegradation of BTX vapors under the radiation of visible light. The results showed that Ag/AgCl exhibits enhanced visible-light photocatalytic activity compared with AgCl. The strong surface plasmon resonance of metal Ag nanoparticles anchored on the AgCl surface can be responsible for the enhanced visible-light photocatalytic activity of the Ag/AgCl. The influence of the basic operational parameters such as type of BTX, the concentration of BTX, photocatalyst shape, relative humidity, and radiation time on the removal efficiency of BTX was studied. The data obtained from removal tests were modeled by a three-layered feed-forward artificial neural network. The optimized ANN architecture was strong at predicting the removal efficiency of the BTX contaminants with R2 > 0.99 and a very low mean square error. The sensitivity analysis using Garson’s method displayed that all explored process parameters influence the photocatalytic removal of the BTX contaminants. The obtained ANN model is used to predict the photodegradation of BTX at different conditions.

Fabrication of BiVO4/Ag2CrO4 heterojunction composites modified with graphene oxide for enhanced photoelectrochemical and photocatalytic performance.

A novel GO/BiVO4/Ag2CrO4 heterojunction photocatalyst was prepared by depositing Ag2CrO4 on the highly active (040) facet of BiVO4, followed by incorporating graphene oxide (GO) through an in situ precipitation method. This synergistic modification of BiVO4 by Ag2CrO4 and GO results in excellent photocatalytic performance, with a degradation efficiency of 94.6% coupled with a maximum rate constant of 0.223 min-1, which is 2.40, 2.19 and 0.66 times higher than that of BiVO4, Ag2CrO4, and BiVO4/Ag2CrO4, respectively, for the degradation of ciprofloxacin (CIP) under visible light irradiation. The degradation efficiency of ciprofloxacin was evaluated using total organic carbon (TOC) analysis. Under investigated conditions, the GO/BiVO4/Ag2CrO4 photocatalyst achieved a TOC reduction of 63.4%. The enhanced photocatalytic performance is attributed to the beneficial role of GO in facilitating electron transport for photo-charge carrier migration, leading to strong interfacial coupling between BiVO4 and Ag2CrO4, which in turn promotes efficient charge separation and transfer. The physicochemical properties of the fabricated heterojunction photocatalysts were characterized using X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) coupled with energy-dispersive X-ray (EDX) analysis, Brunauer-Emmett-Teller (BET) analysis, Fourier-transform infrared (FTIR) spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS), and photoluminescence (PL) emission spectroscopy, while the photoelectrochemical properties of the fabricated photocatalyst were investigated through electrochemical impedance spectroscopy (EIS), Mott-Schottky plots, and photocurrent response analysis. The scavenging experiment was conducted to confirm the role of H+ and ·O2 - in the photocatalytic degradation of ciprofloxacin, which aids in proposing probable degradation mechanism for ciprofloxacin under visible light irradiation. Hence, this study offers an effective strategy for fabricating heterojunction photocatalysts aimed at enhancing the photodegradation of pollutants in wastewater.

Environmentally benign synthesis of NiO nanoparticles: Potential catalysts for Knoevenagel condensation with promising anti-cancer and anti-diabetic activities

With rising environmental awareness, there is an increasing demand for sustainable practices, leading to the growing popularity of green synthetic methodologies that focus on simplicity and non-toxicity. The study presents an efficient eco-friendly route for synthesizing nickel oxide nanoparticles using the Punica granatum L. fruit juice extract. The synthesized nanoparticles were characterized by Ultraviolet–visible Diffuse Reflectance Spectroscopy (UV–Vis DRS), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Dynamic Light Scattering (DLS), Zeta potential and Brunauer-Emmett-Teller (BET) analyses. The nanoparticles exhibited a face-centered cubic phase, with an average crystallite size of 10 nm and a nearly spherical shape. The specific surface area of the nanoparticles was found to be 113.73 m2/g. The nanoparticles served as highly effective, heterogeneous, and sustainable catalysts for the Knoevenagel condensation reactions involving various substituted aromatic aldehydes and active methylene compounds under non-toxic and moderate conditions. The reactions proceeded smoothly with excellent product yields in short time frames with convenient work-up procedures, and easy catalyst recovery, exhibiting high Turnover Number (TON) and Turnover Frequency (TOF). The catalytic performance of the nanoparticles remained consistent over five reaction cycles. The nanoparticles showcased significant cytotoxicity against the human liver cancer cell line (HepG2), achieving a 70.28 % inhibition at a concentration of 112.5 μg/mL. Moreover, the nanoparticles exhibited notable anti-diabetic properties by inhibiting the action of alpha-amylase enzyme. An enzyme inhibition of 52.04 % was attained at a nanoparticle concentration of 500 µg/mL, thereby promoting the hypoglycemic effect. Overall, this study showcases innovative applications of NiO nanoparticles synthesized from Punica granatum L. fruit juice extract, including their use as catalysts for the Knoevenagel condensation reactions, as anti-cancer agents against HepG2 cells, and as anti-diabetic agents through alpha-amylase inhibition.

Influence of Ag-concentration on TiO2-supported catalysts for photocatalytic degradation of microplastics PA66 in marine

Over the past few years, microplastics pollution in marine environments has become a global concern. In this study, a series of silver-doped titanium dioxide (Ag/TiO2) photocatalysts were prepared by the photo-assisted deposition method as an alternative approach for the rapid removal of microplastics particles from aqueous media, specifically polyamide 66 (PA66), the major type of microplastics in marine. The physicochemical and optical properties of photocatalysts were analyzed by Scanning Electron Microscopy (SEM), X-ray Energy Dispersion Spectrum (EDS), X-ray Diffraction (XRD), Photoluminescence Spectroscopy (PL), and Ultraviolet-visible Diffuse Reflectance Spectroscopy (UV–vis DRS). The characterization results of the photocatalysts indicated that the appropriate loading of Ag on TiO2 significantly enhanced the optical properties of the catalysts. Specifically, 1.5 % Ag/TiO2 (AT1.5) exhibited the best light absorption performance and the lowest bandgap value, effectively suppressing the recombination of photogenerated electron-hole pairs. Furthermore, a series of photocatalytic degradation experiments confirmed that AT1.5 exhibited optimal performance in degrading PA66. Under UVA irradiation for 4 hours, the photocatalytic degradation of PA66 by AT1.5 resulted in a mass loss of 58.9 %. The degradation rate of PA66 increased with the amount of catalyst. When the mass ratio of AT1.5 to PA66 was 3:1, PA66 experienced 100 % mass loss after 4 hours of UVA exposure. Finally, through qualitative analysis, this study proposed the possible pathways and mechanisms for the photocatalytic degradation of PA66 by Ag/TiO2. Despite the challenges posed by microplastics pollution to marine ecosystems, this research provides a rapid and effective degradation method.

Modulation of ZrO2-Ag2O-MoO3 nanocomposite into ultrasensitive hydrazine electrochemical sensor for environmental remediation

Herein, a facile single-step wet chemical approach was executed for the composition of semiconductor ternary metal oxides (TMO) i.e., ZrO2-Ag2O-MoO3 nanocomposite (NC) in an alkaline medium. For structural as well as morphological elucidation, the calcined nanocomposite was characterized through ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), powdered X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) and Brunauer-Emmett-Teller (BET) analysis. Later, the glassy carbon electrode (GCE) was modified into a highly responsive as well as selective hydrazine (HDZN) electrochemical probe (ZrO2-Ag2O-MoO3-NC/PEDOT:PSS/GCE) by the fabrication of thin layered ZrO2-Ag2O-MoO3 NC onto GCE facilitated by 5 % PEDOT:PSS as conducting polymer binder. While examining the analytical parameters through novel current–potential (I-V) electrochemical approach, for the first time, the newly designed electrochemical probe, as selective hydrazine sensor, happened to own the low detection limit (LOD; 0.028 pM) with greater sensitivity (33.86 μAμM−1cm−2) and broad linear dynamic range (LDR; 0.1 M–1.0 nM) in addition to coefficient of correlation (r)/r2 square (r = 0.9941, r2 = 0.9882) and low limit of quantification (LOQ; 0.093 pM). Furthermore, reproducibility as well as prolonged stability of this newly proposed probe towards hydrazine were also assessed and found to be reliable in short response time. Hence, this work presents an inaugural report about the sensing of HDZN through the newly designed non reported ZrO2-Ag2O-MoO3-NC/PEDOT:PSS/GCE via an economical as well as novel electrochemical, current–potential (I-V), approach. Additionally, this proposed method is equally responsive towards both environmental and extracted real samples analysis on large scale.

Enhancing the Light‐Driven Photocatalytic Degradation Activity of ZnO Nanoparticles With the Synergistic Incorporation of Er and Tb Elements

ABSTRACTThe existence of organic pollutants in aqueous media has become a vital issue and a critical threat to human health, where organic toxic dyes represent the major contaminants in wastewater. Over the past few years, photocatalytic techniques have garnered a lot of interest in dye removal from wastewater. In this study, a series of ErxTbxZn1 − 2xO nanophotocatalysts (where x = 0.00, 0.01, 0.03, and 0.05) were synthesized and coded as ZET0, ZET1, ZET2, and ZET3 NPs (nanoparticles). The chemical and physical characteristics of the NPs were investigated using Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy‐dispersive X‐ray (EDX) spectroscopy, and ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS) techniques. Further examination by performing photocatalytic experiments, ZET1 NPs demonstrated effective Rhodamine B (RhB) dye degradation within 60 min. It was found that the kinetic rate constant values were 0.008, 0.097, 0.050, and 0.040 min−1 for ZET0, ZET1, ZET2, and ZET3 NPs, respectively. Aside from their remarkable photocatalytic degradation efficiency, these ZET1 photocatalysts are highly stable even after five consecutive cycles. In addition, the active species test revealed that the primary oxidation species involved in the photocatalytic process are holes (h+) and hydroxyl radicals (•OH), and a possible photocatalytic mechanism for degrading RhB by ZET1 photocatalysts was tentatively proposed. The enhancement of the photocatalytic degradation efficiency is due to the low recombination rate of photogenerated charge carriers, as well as a strong synergistic impact of Tb, Er, and ZnO components. Thus, the current study could offer a versatile strategy for the design of new and effective nano photocatalysts for wastewater purification in the future.

Spherical magnetic MgO-CeO2-Fe3O4@JB heterojunction for enhanced photodegradation of pesticide and complex anionic dyes: Understanding the degradation process and diverse water systems

Clothianidin (CLO) is a widely utilized pesticide recognized as an emerging pollutant capable of contaminating surface and subsurface water sources. Utilizing nanoparticles for photodegradation is a very ecological and cost-effective method for water treatment. This study involves the creation of a MgO-CeO2-Fe3O4@JB (Jute-Biochar) heterojunction with a mesoporous structure using hydrothermal process. The purpose of this design is to explore its potential for photocatalytic applications. PXRD (Powder X-ray Diffraction), FTIR (Fourier Transform Infrared), UV–DRS (Ultraviolet–Visible Diffuse Reflectance Spectroscopy), PL (Photoluminescence), TEM (Transmission Electron Microscopy), EDX (Energy Dispersive X-ray), XPS (X-ray Photoelectron Spectroscopy), VSM (Vibrating Sample Magnetometry), BET (Brunauer Emmett Teller), and SEM (Scanning Electron Microscopy) analysis confirmed the formation of a mesoporous MgO-CeO2-Fe3O4@JB heterojunction with preferred interface between MgO, CeO2, and Fe3O4 phases, extending the light-absorption insights to 700 nm. The photocatalytic performance of MgO-CeO2-Fe3O4@JB heterojunction was evaluated under visible-light using CLO as the target molecule. The degradation performances of CLO on MgO-CeO2-Fe3O4@JB were determined to be 95.24 ± 1.18 % after 35 min of exposure to light. The calculated rate constants for the degradation of CLO in presence of light using the MgO-CeO2-Fe3O4@JB composite were determined to be 0.0924 min−1. Furthermore, two complex dyes, Niagara Blue (NB) and Reactive Red (RR), photodegrade to 99.45 ± 1.24 % and 97.23 ± 1.41 % within 25 and 30 min, respectively. The excellent photocatalytic characteristics of the MgO-CeO2-Fe3O4@JB heterojunction were suggested to be primarily caused by the larger photo-response, aligned band-structure, and useful use of the photo-induced charge carriers of the photocatalyst. In addition, the recycling experiments have verified the exceptional photostability of the MgO-CeO2-Fe3O4@JB photocatalyst due to incorporation of nanoparticles into the biochar matrix. This leads to a synergistic mechanism for effectively eliminating these pollutants.

Insights into the expeditious photocatalytic performance of greenly fabricated CeVO4 nanoparticles using Polyalthia longifolia leaf extract

The application of nanomaterials to address environmental challenges has evolved substantially to eliminate pollutants from wastewater as part of environmental cleanup, a growing important research arena. Using green photocatalysts is a noteworthy and economical method that significantly advances environmentally sustainable remediation. This work disclosed the bio-inspired production of cerium vanadate nanoparticles (CeVO4 NPs) were prepared through a green chemistry protocol employing Polyalthia longifolia leaf extract. Key traits of CeVO4 nanoparticles were determined by applying a variety of characterization tools, including X-ray diffraction (XRD), Raman, Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UVDRS), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), and high-resolution transmission electron microscopy (HRTEM). CeVO4 nanoparticles displayed a pseudo-spherical topology with a particle size of 17.77 nm, and the band gap was determined as 2.76 eV. The photocatalytic ability of the as-produced CeVO4 NPs was scrutinized for the decomposition of Congo red (CR) dye. Under optimal conditions, the fabricated CeVO4 nanoparticles demonstrated excellent Congo red dye degradation performance. The effect of hydrogen peroxide (H2O2) dosage, nanoparticle dosage, dye concentration, contact time, scavenging test, and reusability of prepared photocatalyst had an excellent impact on dye decomposition ability. The findings revealed that in just 8 min, 97.79 % of the CR dye had been degraded completely. The pseudo-first-order (PFO) kinetics model aligns with the CR dye decomposition kinetics. In conclusion, this study describes the fabrication of a CeVO4 photocatalyst that exhibits impressive performance, particularly in natural sunlight, suggesting that it could be used in wastewater treatment.

Enhanced Specific Capacitance and Cycling Stability of Li2Cu2(MoO4)3 of NASICON Family of Supercapacitor Applications

AbstractNASICON electrode materials exhibit a broad spectrum of electrochemical potentials, robust ionic conductivity, and structural and thermal stabilities. Using solid state reaction method, Li2Cu2(MoO4)3 was synthesized, a member of NASICON family of compounds based on molybdenum. Various analytical techniques employed to assess structural and morphological properties of synthesized nanomaterial. X‐ray diffraction (XRD) pattern indicated that generated Li2Cu2(MoO4)3 nanomaterial exhibited orthorhombic crystalline structure, with crystallite size of approximately 48 nm. The nanomaterial morphology was evaluated using field emission scanning electron microscopy (FESEM), showing columnar‐ or fiber‐like morphology composed of some conductivity points. The elemental composition of Li2Cu2(MoO4)3 was analyzed by EDAX analysis, confirming the presence of elements lithium, copper, molybdenum, and oxygen. The optical properties and band gap of Li2Cu2(MoO4)3 were analyzed by ultraviolet visible diffuse reflectance spectroscopy (UVDRS). Elemental composition of surface along with electronic states and oxidation states of component present in the nanomaterial Li2Cu2(MoO4)3 were investigated from X‐ray photoelectron spectroscopy (XPS). Electrochemical evaluation using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopic (EIS) showed a specific capacitance of 250 F g−1 at 3.5 A g−1 with the high retention rate of 95.82% after 3000 cycles, indicating its potential for high performance supercapacitors.

Synthesis of tin selenide nanoparticles using Polygonum avicular extract decorated on graphitic carbon nitride for enhancing photodegradation of amoxicillin trihydrate and photoproduction of hydrogen peroxide

In this research, tin selenide nanoparticles (SnSe-NPs) were synthesized using Polygonum avicular extract via the hydrothermal method and decorated on graphitic carbon nitride (g-C3N4) by the simple sonicated method to produce SnSe/g-C3N4 composites. The characterization and properties of the SnSe/g-C3N4 composites, as compared to pristine SnSe and g-C3N4, were determined by Fourier-transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscope, transmission electron microscopy, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, Mott-Schottky, and electrochemical impedance spectroscopy. As a result, the SnSe-NPs possessed the rod-like shape and after the decoration onto the g-C3N4 sheet surface, it reduced the bandgap energy of the g-C3N4 from 2.58 downward 1.43 eV. Besides, the photoactivities of the 10-SnSe/g-C3N4 catalyst were investigated via both sides of amoxicillin trihydrate (AMXT) photodegradation and hydrogen peroxide (H2O2) photoproduction, in which the results were achieved 87.84 % AMXT and 85.48 μM H2O2, respectively, under visible light. Furthermore, the photodegradation was consistent with the pseudo-first-order kinetics and it performed the highest photodegradation at pH ∼5, while the importance of isopropyl alcohol as a trapping agent and •O2− radicals was affirmed in the H2O2 photoproduction. Moreover, the photoproduction of H2O2 was remained after 4 cycles achieved at 62.70 % in the final cycle, which demonstrated the stability and reusability of the 10-SnSe/g-C3N4. These aforementioned results demonstrate that the SnSe/g-C3N4 material is a promising candidate for addressing environmental pollution and energy scarcity issues.

Toward combined photo-electrochemical system for degradation of ceftriaxone contaminated water over Ti-based mixed metal oxide photoanodes performance evaluation and mechanism insights

BackgroundAs a growing environmental concern over the accumulation of antibiotics in aquatic environmets, the development of an efficient degradation process has been addressed. In this study, the application of the photo-electrochemical oxidation (PEO) process for the degradation of ceftriaxone was evaluated. MethodsExperiments were performed in an undivided cell equipped with Ti/IrO2 (0.1)-Ta2O5 (0.1)-TiO2 (0.8) and Ti/IrO2 (0.2)-Ta2O5 (0.2)-TiO2 (0.6) as anodes and Platinum (Pt) sheet as the cathode of the degradation process. Anodes were characterized using scanning electron microscopy (SEM), mapping energy dispersive X-ray (EDS-mapping), ultraviolet–visible diffuse reflectance spectroscopy (DRS), and atomic force microscopy (AFM). Cyclic voltammetry (CV) and photocurrent analysis were performed to consider the photo-electrochemical behavior of anodes. The effect of operational parameters, including initial pH (3–9), ceftriaxone initial concentration (C = 10–50 mg L−1), current density (I = 100–500 mA cm−2), and Na2SO4 as electrolyte concentration (Celectrolyte = 0.05–0.25 mg L−1) on ceftriaxone removal efficiency were determined. Significant findingsOutcomes of experiments revealed that under optimum conditions (pH = 6, C = 30 mg L−1, Celectrolyte = 0.1 mg L−1, and I = 300 mA cm−2), 98.6 % of degradation efficiency was achieved. The combined process resulted in 77.6 and 69.3 % total organic carbon removal of ceftriaxone on Ti/IrO2 (0.1)-Ta2O5 (0.1)-TiO2 (0.8) and Ti/IrO2 (0.2)-Ta2O5 (0.2)-TiO2 (0.6) after five hours of PEO process, respectively. Additionally, the feasible intermediates of ceftriaxone degradation were identified using Gas chromatography-mass spectroscopy (GC-MS) analysis.

Direct synthesis of Cu-TiO<sub>2</sub>-SBA-16 photocatalysts and its application for the oxidative desulfurization of fuel oil model

In this study, the Cu-TiO2-SBA-16 photocatalytic materials were successfully prepared by direct hydrothermal synthesis method. The products were characterized by X-ray diffraction (XRD), Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS) methods. The analysis illustrated that Cu-TiO2 nanocrystals were successfully incorporated into the SBA-16 mesopores. The photocatalytic activity of these Cu-TiO2-SBA-16 mesoporous materials have been tested by the oxidative desulfurization reaction of dibenzothiophene (DBT) using H2O2 as an oxidant under UV light irradiation. The results showed that the Cu-TiO2-SBA-16 mesoporous materials prepared at the Cu/Ti mole ratios of 0.05 showed higher photocatalytic activity than the rest due to the decrease in band gap energy.

Development of Z-scheme BiVO4/g-C3N4/rGO heterojunction nanocomposite for enhanced photocatalytic degradation and antibacterial activity

In this study, we synthesized a novel BiVO4/g-C3N4/rGO (BGR) heterojunction photocatalyst using the hydrothermal method. The synthesized catalysts were characterized through X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX), Transmission Electron Microscopy (TEM), and Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-DRS) to analyze their structural, morphological, and optical properties. The hybrid BGR nanocomposite displayed remarkable absorption characteristics, photocatalytic activity, and notable stability. Photocatalytic degradation performance was evaluated against methylene blue (MB) and indigo carmine (IC) dyes. The BGR ternary hybrid nanocomposites demonstrated significant photocatalytic degradation efficiency, achieving removal rates of 95.6 % for MB and 97.5 % for IC dyes within 120 min. The improved photocatalytic efficiency of the ternary photocatalyst is attributed to superior electron-hole pair separation and the formation of the heterojunction structure. The BGR nanocomposite exhibited excellent recyclability, maintaining its activity and crystalline characteristics over five photodegradation cycles. Additionally, the antibacterial activity of the BGR nanocomposites against Staphylococcus aureus,Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa was evaluated under UV–visible light exposure. This study provides insights for designing efficient visible-light-driven photocatalysts for environmental remediation purposes.

Advanced Z-scheme H-g-C3N4/Bi2S3 nanocomposites: Boosting photocatalytic degradation of antibiotics under visible light exposure

Abnormal concentrations of antibiotics found in aquatic environments have raised serious environmental concerns. For the efficient degradation of antibiotics, it is necessary to develop photocatalysts that react to visible light. In this work, calcination and hydrothermal methods were used to synthesize bare H-g-C3N4 and Bi2S3, respectively. Various analytic methods, such as XRD, XPS, FT-IR, HR-SEM, and HR-TEM, were utilized to verify the accomplished synthesis of the materials produced. The results of ultraviolet–visible diffuse reflectance spectroscopy (UV–DRS) showed that the synthesized nanocomposites exhibited a lower band gap than the bare materials and thus greater visible-light absorption. The degradation efficacy of the bare materials and hydrothermally synthesized nanocomposites over ciprofloxacin were investigated. A high degradation efficiency of 92 % was demonstrated for ciprofloxacin using the H-g-C3N4/Bi2S3 (5 %) nanocomposite. This remarkable efficiency underscores the potential of this nanocomposite in removing antibiotic pollutants from wastewater. In addition, the electron transfer dynamics amid the two materials (H-g-C3N4 and Bi2S3) within the heterojunction was elucidated. The findings provide valuable insights into the mechanisms underlying the enhanced photocatalytic activity of nanocomposites, paving the way for further optimization and development of advanced photocatalytic systems for environmental remediation.

Biosynthesis of TiO2/CuO and Its Application for the Photocatalytic Removal of the Methylene Blue Dye.

In this study, we successfully synthesized a TiO2/CuO nanocomposite using the aqueous extract of Impatiens tinctoria A.rich. leaf extract as a capping, reducing, and stabilizing agent for the first time in an environmentally friendly, low-cost, straightforward, and sustainable technique. Numerous characterization techniques such as ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS), photoluminescence (PL), Raman spectroscopy, Fourier-transform infrared (FTIR), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and high resolution TEM (HRTEM) were used to characterize the obtained TiO2/CuO nanocomposite. XRD verified that the TiO2/CuO nanocomposite has an average crystallite size of about 21 nm. The TEM result revealed an average particle size of 29 nm for the biosynthesized TiO2/CuO NC. The HRTEM analysis showed the presence of polycrystalline structures with the predominant lattice fringes 0.352 and 0.19 which were attributed to anatase phase TiO2 in the crystal plane of (101) and (200), respectively. The lattice fringes for monoclinic CuO were observed with values of 0.213 and 0.252 for the lattice planes of (111) and (111̅), respectively. The photoluminescence spectroscopic analysis revealed that the TiO2/CuO NC showed the lowest intensity compared to the pristine TiO2 and CuO indicating the reduction of exciton recombination in the case of the TiO2/CuO NC. The BET analysis showcased the formation of mesoporous materials with a surface area of 87.5 m2/g. The photocatalytic degradation performance of the biosynthesized TiO2, CuO, and TiO2/CuO nanomaterials against the potentially harmful MB dye was tested using the light source of a 150 tungsten-halogen lamp with a wavelength range of 360-2800 nm. The factors affecting photodegradation efficiencies like catalyst dose (20 mg), dye concentration(15 ppm), pH (9), and reaction time (90 min) were optimized for the degradation of the MB dye. The TiO2/CuO catalyst showed the highest degradation efficiency of 99% under the optimized conditions. The degradation rate of the MB dye in the presence of the TiO2/CuO NC was evaluated and found to be fitted to the pseudo-first-order kinetics with a rate constant of 0.03 min-1. The reusability test of the TiO2/CuO catalyst showed its good stability.

Biosynthesis of Ag‐CuO Nanocomposites: Efficient Catalyst for the Synthesis of Schiff Bases, Photodegradation of Congo Red Dye and Their Cytotoxicity Evaluation on MCF‐7 Cell Line

ABSTRACTAmid growing environmental concerns and the need for a sustainable future, green synthetic methodologies are gaining popularity for their simplicity and nontoxicity. In pursuit of the eco‐friendly synthesis of nanomaterials, the study reports an innovative synthesis of Ag‐CuO nanocomposites via the coprecipitation method utilizing Citrus limetta fruit juice extract as the bioreductant and stabilizing agent. The morphological and structural characteristics of the fabricated nanocomposites were evaluated by ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX), transmission electron microscopy (TEM), X‐ray diffraction (XRD), Raman and Brunauer–Emmett–Teller (BET) analyses. The nanocomposites were crystalline with particle sizes ranging from 15 to 24 nm and exhibited spherical and rod‐like shapes. The band gap value and specific surface area of the nanocomposites were found to be 1.5 eV and 25.50 m2/g, respectively. The photoluminescence (PL) analysis and electrochemical studies revealed significant charge separation and effective charge migration behaviour of the nanocomposites, respectively. The nanocomposites effectively catalysed the synthesis of Schiff bases from aryl aldehydes and aromatic amines at room temperature and without solvents. The reactions proceeded in a brief time with excellent product yields, and the nanocatalyst retained its activity for five consecutive cycles. The nanocomposites also efficiently catalysed the photodegradation of Congo red dye under visible light. A significant degradation of 94.33% was attained in 55 min, and the nanocatalyst maintained its efficacy over four consecutive reaction cycles. Moreover, the nanocomposites exhibited notable anticancer properties against the MCF‐7 (human breast) cell line, demonstrating a remarkable cytotoxicity rate of 87.79%. The findings highlight the efficacy of the biosynthesized nanocomposites in catalysis, environmental remediation and biological applications.

Preparation of Bi@Ho3+:TiO2/Composite Fiber Photocatalytic Materials and Hydrogen Production via Visible Light Decomposition of Water

Using electrospun nanofibers doped with TiO2 and rare-earth ion Ho3+ as the matrix, and sodium gluconate as the reducing agent, Bi(NO3)3 was reduced using hydrothermal technology to produce Bi@Ho3+:TiO2 composite fiber materials. The materials’ phase, morphology, and photoelectric properties were characterized using various analytical testing methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), and transient photocurrent (IP). During the hydrothermal process, it was confirmed that Bi3+ was reduced by sodium gluconate to form pure Bi nanoparticles, which combined with Ho3+:TiO2 nanofibers to form heterojunctions. By leveraging the surface plasmon resonance (SPR) effect of metallic Bi and the abundant energy level structure and 4f electron transition properties of rare-earth Ho3+, the TiO2 nanofibers underwent dual modification, effectively enhancing the photocatalytic activity and stability of TiO2. Under visible light irradiation, the rate of hydrogen production through water decomposition reached 43.6 μmol·g−1·h−1.