DRS Analysis Research Articles

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.

Novel framework-confined Cu@ 13X catalyst with excellent resistance to toxic SO2 as an eco-friendly substitute for hazardous V-based NH3-SCR catalyst

V2O5-WO3/TiO2 (VWTi) catalyst has long been utilized in fixed source flue gases to purify harmful NO gas. However, VWTi is classified as a hazardous material because of its harm to human health and environment. To address this issue, a low-cost green Cu-based zeolite catalyst (Cu@13X) with a wide temperature range was synthesized using an in-situ hydrothermal method. This method is intended to control the adsorption capacity of toxic SO2 by regulating the location of Cu species. UV-Vis DRS and EXAFS analyses revealed that a significant amount of Cu was encapsulated within the 12-membered ring pores of the 13X molecular sieve. SO2-TPD and DFT calculations further indicated that Cu@ 13X exhibits reduced SO2 chemical adsorption capacity. Consequently, this green catalyst demonstrated superior catalytic performance, maintaining superior NOx conversion for over 70 h in the mixture gas containing 250 ppm SO2; while the Cu/13X catalyst lacked NH3-SCR catalytic activity under the same conditions. Moreover, Cu@ 13X catalyst also has excellent NH3-SCR catalytic performance in low temperature flue gas below 250 °C, which is significantly better than the hazardous VWTi catalyst. Characterization techniques such as NH3-TPD, H2-TPR, and XPS confirmed that the Cu@ 13X catalyst possesses excellent acidity, robust redox capabilities, and abundant surface defects. In-situ DRIFT spectra further illustrated that the NH3-SCR reaction on the catalyst surface adheres to the Eley-Rideal mechanism both before and after the introduction of toxic SO2. This study offers a fresh perspective on the development of framework-confined NH3-SCR catalysts and elucidates the mechanism behind the sulfur resistance of these catalysts. And the green Cu@ 13X catalyst is anticipated to serve as an effective alternative to the hazardous VWTi catalyst.

Visible‐Light Photocatalytic Activity of a Novel TiO2/g‐C3N4/CuFe2O4 Nanocomposite in Degradation Amoxicillin, Chlorpyrifos and Methylene Blue

AbstractA novel TiO2/g‐C3N4/CuFe2O4 nanocomposite is synthesized via a wet impregnation process and has been evaluated for photocatalytic degradation of organic pollutants such as Amoxicillin (Antibiotic), Chlorpyrifos (Pesticide), and Methylene blue (Dye) under dark and visible light conditions in water. The synthesis and its photocatalytic characterization of nanocomposite are analyzed using XRD, FT‐IR, HR‐SEM, TEM, EDS, XPS, UV‐Vis, DRS, PL, BET, EIS, VSM, and ESR analysis. Among the various organic pollutants analyzed using TiO2/g‐C3N4/CuFe2O4 to serve as a photocatalyst, the degradation of MB pollutant was significantly greater (99.5 %, k=0.0533 min−1) in comparison to the degradation of the AMX (97.6 %, k=0.0346 min−1) and CPF (97.3 %, k=0.0340 min−1) during visible light irradiation for a period of 90 minutes. The recyclability is validated over three cycles, displayed its stability with 76 % degradation of pollutants and the photocatalyst is also easily separated using a simple magnet for further recycling study. As observed in the results of ESR, the formation of O2 significantly accelerated the superoxide radical generation during the photocatalytic degradation of pollutants, enhancing degradation efficiency. It is worth highlighting that the remarkable degradation efficacy, stability and reusability exhibited by the synthesised nanocomposite prove advantageous for subsequent applications.

Construction of Ba-doped Ag3PO4/SnO2 type-II nanocomposites as a promising photocatalyst for boosting photocatalytic degradation of BY28 dye and redox conversion of Cr(VI)/Cr(III)

In the present study, Ba-doped Ag3PO4/SnO2 type-II heterojunction nanocomposites were fabricated and systemically investigated for the degradation of basic yellow 28 (BY28) dye and Cr(VI) reduction in the photocatalytic process under visible-light irradiation. XRD, XPS, FESEM, DRS, and PL analyses were performed to determine the characterization of synthesized photocatalysts. The optimal 1.5 wt% Ba-doped Ag3PO4/SnO2 nanocomposite exhibited an efficient photocatalytic activity with rate constant of 0.0491 min−1 for BY28 degradation and 0.0261 min−1 for Cr(VI) reduction, which is 13.3 and 7.5 times higher than that of the SnO2 nanorods. Such enhanced performance can arise from the one-dimensional structure, extended light absorption toward the visible region, formation of the type II heterojunction, the new defect-related energy states, and efficient charge separation. Furthermore, the photostability of the photocatalysts was studied and a plausible photocatalytic mechanism was proposed.

Electrospun Mn1-xCoxFe2O4 (x=0–0.7) nanofibers for supercapacitors and oxygen evolution reaction

Cobalt manganese ferrite nanofibers (Mn1-xCoxFe2O4; x = 0, 0.3, 0.5, 0.7), were synthesized using sol-gel electrospinning technique. The impact of cobalt incorporation on physical and electrochemical properties of manganese ferrite nanofibers was investigated. The XRD peaks confirmed the formation of a cubic spinel phase and lattice parameter decreased gradually with increasing cobalt concentration. SEM analysis revealed the nanofibers with diameters in the range of 30–60 nm. VSM analysis showed that magnetic parameters such as coercivity, and saturation magnetization were enhanced by cobalt substitution and the sample Mn0.3Co0.7Fe2O4 showed the highest saturation magnetization and coercivity. DRS analysis exhibited that the incorporation of cobalt in the manganese ferrite reduced the band gap energy. The supercapacitive performance of Mn1-xCoxFe2O4 electrodes was investigated using CV, GCD and EIS in 3 M KOH electrolyte solution. The highest specific capacitance (453 F g−1) was obtained with long cycling stability (94.6 % retention after 4000th cycles) for Mn0.7Co0.3Fe2O4. Furthermore, an asymmetric supercapacitor (ASC) was made with reduced graphene oxide (rGO) and Mn0.7Co0.3Fe2O4 as anode and cathode electrodes, respectively. The Mn–CoFe2O4//rGO ASC revealed an impressive energy density of 50.2 Wh kg−1 at a power density of 750 W kg−1. The electrocatalytic oxygen evolution reaction (OER) performance of the Mn0.7Co0.3Fe2O4 and MnFe2O4 catalysts were also investigated in 1 M KOH alkaline electrolyte. Experiments demonstrated that the Mn0.7Co0.3Fe2O4 nanofiber catalyst had a lower overpotential (201 mV) at 10 mA cm−2, a small Tafel slope (106 mV dec−1), a larger ECSA (176 cm2), a greater TOF (7.68 × 10−4 s−1), and better long-term durability (96.3 % for 12 h) than MnFe2O4 for OER. This highlights the potential of the synthesized Mn0.7Co0.3Fe2O4 electrode for supercapacitor and oxygen evolution reaction.

Novel synthesis of vanadium phosphorus/ cerium promoted manganese oxide (VPO/Ce-OMS-2) nanocomposite as an efficient and selective catalyst for the aerobic oxidative coupling of benzyl alcohol and aniline to imine in the liquid phase

In this investigation, the VPO/Ce-OMS-2 composite was synthesized via the mechanochemical method and it was employed for the synthesis of imine in the liquid phase through a two-step process of oxidation of benzyl alcohol and subsequent condensation with aniline using air as an oxidant. The composite was synthesized with different mass ratios of (1:1), (1.5:1), (2:1) and (2.5:1). The effect of the VPO/Ce-OMS-2 mass ratio on catalyst activity has been investigated. As the mass ratio increases from (1:1) to (2:1), the benzyl alcohol conversion gradually increases, reaching 93% at a (2:1) mass ratio. Among the synthesized samples, the VPO/Ce-OMS-2(2:1) composite exhibited the highest selectivity towards imine formation and conversion of benzyl alcohol. Various techniques, such as XRD, FT-IR, BET, FESEM, EDX, DRS, NH3-TPD, and HRTEM, were utilized to characterize the catalysts. Results indicated that the composite synthesized with a (2:1) mass ratio has a favorable surface area, a mixture of micro-meso structures, and a high number of acidic sites, as confirmed by BET-BJH and NH3-TPD techniques. The DRS analysis demonstrated that the interaction between the two catalysts, VPO and Ce-OMS-2, enhances the selectivity for the desired product. The results clearly show the synergism effect in the combination of components VPO and Ce-OMS-2 and improving the activity and selectivity of the synthesized nanocomposite. The effects of reaction temperature, reaction time, solvents, VPO/Ce-OMS-2 mass ratio, catalyst amount, and reusability were studied. Recycling results for the VPO/Ce-OMS-2(2:1) composite show that the benzyl alcohol conversion decreases slightly after five cycles of use, and its stability is almost maintained. Optimizing the reaction conditions (0.2 g catalyst, VPO/Ce-OMS-2 mass ratio (2:1), solvent toluene, reaction temperature 90°C, and t = 8 h) resulted in a 93% conversion of benzyl alcohol with complete selectivity for the imine.

One-pot construction of α-Fe2O3/ZnNiFe2O4 heterojunction by incomplete sol/gel-self-propagating method with choline chloride-ethylene glycol media and its photo-degradation performance

A magnetic α-Fe2O3/ZnNiFe2O4 composite photocatalyst was synthesized through a one-pot reaction employing choline chloride-ethylene glycol deep eutectic solvents and an incomplete sol-gel self-propagating method. The photocatalytic performance was assessed by removing methylene blue (MB) under 40 W visible light. With a 1.0 g/L catalyst dosage, 10 mg/L MB concentration, and pH levels of 6 and 12, removal rates of 97 % and 99 % were achieved within 90 min, respectively. The composite also demonstrated effective degradation of methyl orange (MO) and malachite green (MG). Stability tests revealed minimal reduction in photocatalytic activity after four cycles. Active species analysis identified ·O2⁻ and ·OH as the primary agents in the photocatalytic process. XRD, XPS, UV–VIS DRS, HRTEM, PL, and EIS analyses confirmed the formation of a Z-scheme heterojunction between ZnNiFe2O4 and α-Fe2O3, which enhanced the specific surface area, electron transport capacity, and narrowed the band gap. This heterojunction improved the separation efficiency of photogenerated electron-hole pairs, resulting in enhanced photocatalytic activity and stability. This study presents a novel approach for preparing Z-scheme heterojunction photocatalysts through a one-pot reaction.

Evaporation-induced self-assembly Al doped black TiO2 for the degradation of tetracycline hydrochloride under visible light

Light absorption range, recycling stability and charge transfer efficiency are key to the performance of photocatalytic material. Based on these targets, a Al doped TiO2 catalyst was synthesized by the evaporation-induced process, after processed by NaBH4 reduction, the black TiO2 doped with Al was finally prepared. Uv-vis DRS, EPR and XPS analyses confirm the expanded light absorption window (300 nm - 1000 nm) and the introduction of abundant oxygen vacancy after the reduction process. The final product BTiO2/Al-0.5 has a degradation rate of about 84 % over the tetracycline hydrochloride within 60 minutes, the reaction rate constant (k) is 10.6 times higher than the unreduced sample. The dramatic change of photocatalytic ability can be assigned to the broadened visible light absorption, increased charge separation efficiency, narrowed band gap and defect-enriched oxygen vacancy. This work offers insights into the fabrication of TiO2 catalyst and the introduction of oxygen defect.

Degradation of tetracycline hydrochloride through g-C3N4/TiO2 nanotube arrays for photoelectrocatalytic activation of PMS system: Performance and mechanistic analysis

To enhance the pollutant degradation ability of TiO2 nanotube arrays (TNAs) in a photoelectrocatalytic system (PEC), g-C3N4/TNAs photoanode was synthesized using anodic oxidation-slow evaporation method. Then, peroxymonosulfate (PMS) was incorporated and the resulting PEC-PMS system was applied to degrade tetracycline hydrochloride (TCH). The results from SEM, XRD and UV–vis DRS analyses indicated that g-C3N4 was successfully loaded onto the surface of TNAs, reducing the forbidden bandwidth from 3.10 eV to 2.89 eV. I-t and EIS curves demonstrated that the loading of g-C3N4 increased the electron transfer rate of TNAs. The photoanode prepared with a g-C3N4 solution (concentration of 100 mg L−1) exhibited the best degradation performance for TCH. The degradation rate of TCH by the PEC-PMS system reached 95.69 % at a TCH concentration of 10 mg L−1, pH of 9, PMS dosage of 2 mM, and voltage of 2 V, significantly higher than that of the PEC system without PMS (35.14 %). The contribution of active radicals to the system was in the order of SO4·- > h+ > ·O2- > ·OH. Three possible pathways for TCH degradation were proposed based on the experimental results. In conclusion, this work provides a theoretical basis for the preparation of photoelectrodes responsive to visible light and their application in the degradation of pollutants by the PEC-PMS system.

Fabrication and characterization of CaO and B2O3 doped silicate glasses

Lead silicate glasses are used to absorb electromagnetic waves. This work investigates the radiation shielding properties of a xSiO2.(1-x)PbO2 glass system containing 5 and 10 mol% of CaO and B2O3. Analyses for characterization include XRD, SEM, EDAX, DRS (UV–Vis), and density analyses. Here, DRS (UV–Vis) analysis is used to investigate the absorption value in the range of 200–900 nm, and XCOM software is used to investigate the γ-ray wavelength. UV–Vis analysis specifies that the absorption value in the UV-ray wavelength increases by increasing the contents of CaO and B2O3, while the XCOM software shows that the absorption value in the γ-ray wavelength decreases with the addition of CaO and B2O3. It seems that the effect of different oxides on the properties of lead silicate glasses is complex and depends on the position of the elements. The results show that glass transparency decreases with the addition of CaO and B2O3. The mechanism of the addition of CaO and B2O3 is discussed and compared with the results of other dopants such as ZnO and BaO in this glass. In this research, for the first time, the “inner-atomic” and “outer-atomic” perspectives are presented and discussed to justify the obtained results.

S-scheme mechanism in the TiO2/Cu2O@Cu system toward selective degradation of an electron-rich dye pollutant under solar light

This research aims to reach a selective nanocomposite based on Cu and TiO2 nanoparticles (NPs) through a sol–gel followed by chemical reduction. Various methods such as XRD, SEM, TEM, HRTEM, BET, Raman, FTIR, DRS, XPS and PL analysis were used to characterize the prepared NPs. The reduced nature of Cu in nanocomposite was evidenced by its X-ray photoelectron spectral characteristics and its HRTEM image. Due to the presence of Cu NPs, light absorption in solar radiation by nanocomposite was considerably enhanced and caused more efficient charge carriers separation. A CCD was used to evaluate the photoactivity of the solar-driven photocatalyst by degrading methylene blue (MB) as a single model electron-rich organic pollutant. In optimal conditions, the highest photocatalytic activity reached 95.64 %. In this study, band structure and reactive species scavenging results confirmed an S-scheme mechanism for charge carrier transfer during photodegradation. The plasmonic S-scheme TiO2/Cu2O@Cu heterojunction photocatalyst exhibited remarkably strong photocatalytic selectivity toward MB in binary mixtures of MB with eosin B and rhodamine B. A preference for degradation of MB over safranin (Saf) is confirmed by the faster degradation rate of MB than that of Saf. S-scheme mechanism, Cu doping and dye sensitization all contributed to outstanding selective photodegradation performance.

Sonochemical synthesis of bismuth sulfide-based nanorods for hydrogen production

Bismuth-based nanostructures have been used as promising materials for catalytic hydrogen production. Herein, a sonochemical method was developed to prepare solid solutions like Bi2-xZn1.5xS3 in order to strengthen the Bi2S3 redox ability. Thioglycolic acid (TGA) was used as a complexing agent of Bi3+ to slow down Bi2S3 precipitation, making zinc insertion into the sulfide structure easier. The results of XRD, TEM, EDS, XPS, and DRS analyses suggest the formation of nanocomposites consisting of nanorods of Bi2-xZn1.5xS3 covered by ZnS nanoparticles, with bandgap widening from 1.16 eV (Bi2S3) to 2.37 eV (Bi1.53Zn0.6S3/ZnS/Zn(OH)2). The hydrogen generation in an ethanol aqueous solution was investigated under sonolysis, photocatalysis and simultaneous sonolysis and photocatalysis (sonophotocatalysis) in the presence of bismuth sulfide-based nanorods. The hybrid action of light and ultrasounds determined a remarkable synergistic effect on the hydrogen production of the solid solutions. The most outstanding results were found in the presence of nanocomposites containing Bi2-xZn1.5xS3, which can have an origin in better charge separation after zinc incorporation.

SnO2-TiO2 materials for photocatalytic degradation of cationic dye under UV and visible light and a chitosan composite film investigation

The possibility of SnO2 incorporation and immobilization as films forming composites opens new perspectives for TiO2 to profit visible light and to facilitate the photocatalytic process, respectively. In this study, 0 %, 1 % and 10 % wt. of SnO2 was incorporated into TiO2 (SnO2-TiO2) by coprecipitation in a sol-gel method by ammonia addition, followed for calcination at 500 °C. The photocatalysts were characterized by N2 adsorption-desorption, FTIR spectroscopy, XRD Rietveld refinement, TG-DTG, SEM-EDS, DRS and elemental analysis. The performance of all solids was evaluated in the photocatalytic degradation of the cationic dye methylene blue in aqueous phase, under visible and UV irradiation, at 25 °C for 2 h. The results showed that the incorporation of Sn into TiO2 improved the textural properties and decreased the bandgap. All solids presented only TiO2 typical diffractograms, with anatase as the main phase, but catalyst with 10 % SnO2 presented also brookite phase, inferring that Sn atoms were incorporated into TiO2 structure, corroborated by MEV results. All tin-based photocatalysts show high activity under UV and visible light, with the 10 % SnO2 material reaching 83 % and 88 % degradation after 2 h under UV and visible radiation, respectively. This material was tested as an immobilized film, achieving 14 % of decolorization, and the reuse was also evaluated. Our investigation demonstrates that SnO2-TiO2 catalysts could be used to decompose a dye under UV and Visible light as powder in a batch reactor and immobilized as a composite film with chitosan, that opens new perspectives to facilitate the application using solar light.

Exploring photocatalytic tetracycline removal performance under simulated sunlight irradiation: Milling time effect on metallic reduction of MnO/ZrO2 mixed oxide

In the present research, it is reported that ball milling technique can be applied to enhance the photocatalytic properties of MnO and ZrO2 metal oxide powders (MZOx) furthermore the fabricated photocatalyst can be used for the degradation of tetracycline (TTC). XRD analyses revealed that increasing the milling time resulted in the formation of a pure metallic Mn crystal phase, which boosted the antibiotic degradation rate. It was confirmed by SEM technique that the morphological structures of the particles were generally small and uniform. The band gap energy was calculated as 3.70 eV for the hybrid metal oxide. Additionally, the adsorptive and photoluminescence features were illuminated via DRS and PL analyses. The effect of milling time had a major impact on the photodegradation rate of TTC, and the 8 h milling sample (MZOx-8h) exhibited the highest catalytic degradation activity (79.4 %). Low photocatalytic activity was obtained at acidic pHs and increased at alkaline pHs. The presence of H2O2 sharply decreased photocatalytic process time (60 min) and 94.3 % of the TTC was degraded at 7.5 mM H2O2. The photocatalytic degradation process proceeded through superoxide radicals and was supported by holes. The stability of MZOx-8h almost remained constant (70.02 %) even after seven cycles. It was determined that the presence of oxalic acid positively affected the progress of TTC degradation reactions. Further, practical application areas were investigated and MZOx-8h doped on support materials was found to be suitable for such applications in proportion to the doping ratio. Finally, it was demonstrated that MZOx-8h exhibited remarkable performance in photocatalytic reactions of different types of organic pollutants. The synergistic nature of MnO and ZrO2 with the contribution of ball milling time effect resulted in high photocatalytic activity.

Boron modified Ag3PO4 powders for UV and visible light photocatalytic degradation of various dyes

Pure and boron modified Ag3PO4 powders with different boron contents (0–5 wt.%) were prepared. XRD, ATR-FTIR, XPS, SEM-EDX, UV-Vis DRS and PL analyses were conducted for the characterization of the prepared powders. Characterization studies indicated the reduction in the band gap energy, the presence of boron and no change in the morphology due to boron modification. The results of photocatalytic experiments showed that boron modification increased the activity of Ag3PO4. The UV light dye degradation efficiency increased from 63% to 84% for methyl orange (MO) and from 41% to 65% for methyl red by 3% boron modification. The reaction rate constant for MO increased by a factor of 1.7. Under visible light, the activity was similarly enhanced by boron modification. The photocatalytic degradation efficiency increased from 31% to 58% and the reaction rate constant increased by a factor of 2.3 by boron modification for MO under low intensity visible light. These results showed that boron modification enhanced the photocatalytic dye degradation activity of Ag3PO4 under both UV and visible light. This enhancement was attributed to the decrease in the band gap energy and the increase in the interaction of the dye molecules with the photocatalyst surface through boron species.

Microwave-assisted rapid synthesis of ZnO multipod-BiOBr heterojunction on recycled PET plastic waste for photocatalytic degradation of oily wastewater

Heterojunctions based on ZnO multipod and BiOBr were developed on the floating recycled polyethylene terephthalate (PET) and they were used to investigate the photocatalytic degradation of hexane in water emulsion. Characterizations of the synthesized ZnO-BiOBr-PET photocatalysts was performed using XRD, FESEM, EDX, BET/BJH, FTIR, UV-Vis DRS, PL, WCA, and CV analyses. The FESEM results demonstrated that ZnO multipods have been synthesized during the very short time of microwave heating that effectively hosted the highly dispersed BiOBr nanoplates, particularly in the 15 %ZnO-5 %BiOBr-80 %PET sample. The BET/BJH analysis revealed the low surface areas for the synthesized samples, however, the sample with the highest ZnO multipod loading (15 %ZnO-5 %BiOBr-80 %PET) exhibited slightly enhanced surface area due to the highly dispersed BiOBr over the ZnO multipods. The fabricated samples displayed hydrophobicity and liquid marble like behaviour due to the presence of PET, while the variations in the percentages of ZnO and BiOBr strongly influenced the water contact angle. The formation of heterojunction between ZnO multipod and BiOBr was confirmed which lead to a shift in the visible light region, increased the light harvesting, and also reduced the charge carrier recombination in the composite sample of 15 %ZnO-5 %BiOBr-80 %PET. The ZnO-BiOBr-PET photocatalysts were tested for the photocatalytic degradation of hexane in a water emulsion and results indicated that 15 %ZnO-5 %BiOBr-80 %PET could degrade 92.1 % of initial hexane, retaining its performance over four successive runs with only an 11.7 % decrease in activity. Scavenger tests revealed that, in addition to hydroxyl radicals, superoxide also played a significant role in the photocatalytic degradation of hexane. This obervations indicate the efficient capturing and utilizing of O2 by this LMP even in non-oxygenated conditions.

Synthesis and characterization of CuCoFe2O4@GA/AC as a bio-based matrix magnetic nano-heterogeneous photocatalyst for ceftriaxone degradation from aqueous media

Emerging contaminants such as ceftriaxone are a significant issue in the environment. They have led to a series of ecological, environmental, and health issues, and it is urgent to find a green and secure method to remove antibiotics from water effectively. In this research, the CuCoFe2O4@Gum Arabic (GA)/Activated Carbon (AC) as an innovative bio-based matrix magnetic nanocatalyst was synthesized for the efficient degradation of ceftriaxone from aqueous media. The structure of CuCoFe2O4@GA/AC was characterized via FESEM, EDS, Mapping, XRD, FTIR, VSM, and DRS analyses. The structural analysis of the catalyst revealed its synthesis at the nanometer scale (40–50 nm), exhibiting high magnetic strength (Ms: 5.38 emu/g) and favorable optical properties with a bandgap of 3.6 eV. Under optimized conditions, including a pH of 5, 60 min of irradiation time, 0.24 g/L photocatalyst dose, and ceftriaxone concentration of 5 mg/L, the removal efficiency from synthetic and real samples was 94.43% and 62.5%, respectively. The photocatalytic degradation process of ceftriaxone followed pseudo-first-order and Langmuir–Hinshelwood kinetic models. Furthermore, analysis of the process mechanism indicated a prominent role of the superoxide radical. The catalyst had a high recovery capability and chemical stability. The photocatalytic degradation of ceftriaxone by CuCoFe2O4@GA/AC showcased remarkable efficiency, indicating its potential utility in the treatment of wastewater contaminated with antibiotics.

Impact on bandgap, electrical and magnetic properties of SnO2 nanoparticles by cerium and samarium

Synthesis of undoped, Samarium (Sm) and Cerium (Ce) co-doped SnO2 nanoparticles along with their enhancement in structural and physicochemical properties are reported. The samples have been prepared by co-precipitation method. The tetragonal rutile-type structure from PXRD pattern confirms the synthesized materials and obtained an average crystallite size of 23, 19 and 14 nm for the pure, 2 and 4 wt.% of Sm-Ce co-doped SnO2 NPs. The band at 620 cm−1 is assigned to the bonding of metal-oxygen as O-Sn-O bridging bond of SnO2 through FTIR-spectrum. From UV–DRS analysis, bandgap energy is found to be 3.45, 3.38 and 3.26 eV respectively for pure, 2 & 4 wt.% of Sm-Ce co-doped SnO2 NPs. Photoluminescence emission shows a sharp peak centered at 490 nm, a high intensity peaks at 521 and 538 nm due to blue and green emission. Addition of dopants narrowing the bandgap and reduces the dielectric constant as well as the dielectric loss. The dielectric constant and dielectric loss are directly proportional to temperature but inversely proportional to frequency, which shows that both polarizability and the method of charge transfer are impacted by the space charge polarization, which made the material could be a potential candidate in spintronics and high-performance dielectric materials. The effect of Sm-Ce co-dopants enhances the saturation magnetization value from 0.0049067 emu/g to 0.0072245 emu/g. The results exhibit that Sm-Ce (4 wt.%) co-doped SnO2 nanoparticles have strong dielectric and magnetic properties which is a potential candidate for spintronic devices.

In-situ construction of the novel In2S3/BiOIO3 heterojunction with boosted visible-light photodegradation performance for diverse persistent organic pollutants

Designing rational heterojunctions to achieve efficient separation and transmission of photoinduced charge carriers is one of the effective strategies to improve the activity of semiconductor photocatalysts. In this study, the novel In2S3/BiOIO3 binary heterojunctions were facilely synthesized at room temperature using a simple in-situ growth method. The physicochemical properties of the fabricated In2S3/BiOIO3 heterojunction catalyst were investigated using various techniques including XRD, FT-IR, BET, XPS, TEM, UV–vis DRS, PL, EIS, and PC analysis. The In2S3/BiOIO3 composite catalyst possesses suitable band position and bandgap energy and therefore is capable of degrading organic contaminants under visible light irradiation. The optimized composite catalyst with In2S3/BiOIO3 molar ratio of 0.5 (In2S3/BiOIO3-5) exhibited superior photocatalytic activity, achieving 98.6 % degradation rate for Rhodamine B (RhB), far surpassing the performance of the individual components. In addition, In2S3/BiOIO3-5 showed broad-spectrum photocatalytic activity in the decomposition of various organic pollutants including methyl orange (MO), methylene blue (MB), tetracycline (TC) and bisphenol A (BPA). The improved photocatalytic activity of the prepared composite catalysts can be ascribed to the formation of type-II heterojunction, which facilitates the separation and migration of e–/h+ pairs. The excellent photocatalytic properties and favorable structural stability make In2S3/BiOIO3-5 a viable material for degrading various persistent organic pollutants.

A novel S-scheme photocatalyst Fe2O3/Bi2O3/g-C3N4 with enhanced visible-light photocatalytic performance for antibiotic degradation and CO2 reduction: RSM-based optimization

The degradation of pollutants and reduction of CO2 to hydrocarbon fuels using photocatalysis is a potential approach to reducing CO2 emissions and decreasing environmental contamination. This study introduces an innovative S-scheme photocatalyst (Fe2O3/Bi2O3/g-C3N4) synthesized through simple methods for the first time. The structural, morphological, and optical properties of the synthesized photocatalysts were comprehensively characterized using XRD, XPS, FTIR, SEM, TEM, HR-TEM, BET, UV–vis DRS, PL, ESR, and mott-Schottky analyses, respectively. The visible light photodegradation of tetracycline (TC) antibiotic and CO2 conversion were carried out in order to evaluate the photocatalytic performance of these synthesized materials. Using the RSM-CCD approach, the influence of key variables on TC degradation were optimized. The results indicated that the optimized photocatalyst (45-FeBiC) exhibited higher photocatalytic performance (99.87 %) compared to other samples via photogenerated •O2−, and •OH. Additionally, four cycle studies verified that the 45-FeBiC nanocomposite had adequate photostability. After 6 h of visible light illumination, the 45-FeBiC catalyst generated 33.84 μmol/g of CO and maintained 96.2 % of its initial photocatalytic activity after 30 h of reaction. The enhanced photocatalytic efficiency of the 45-FeBiC nanocomposite is attributed to the photosensitization effect of 3 wt%-Fe2O3/Bi2O3 on g-C3N4 within the S-scheme photocatalytic framework.