Unveiling the photocatalytic potential of Co-doped BaBiO3 through facile sol-gel synthesis and comprehensive characterization

ZnO is a semiconductor material that has important physical and chemical properties, which are frequently and significantly enhanced by the addition of impurities, such as doping. A study of the structural properties of pristine and functionalized (i.e., doped with Antimony and Tungsten) ZnO nanoparticles has been conducted for the photocatalyst-based degradation of methylene blue (MB) dye under both Ultraviolet (UV) and solar light. Authors have used a 1% concentration of dopant for doping purposes. The synthesized materials were characterized for structural analysis, functional group identification, spectroscopic measurements, and morphological examination using X-ray diffraction (XRD), Fourier transform-infrared (FTIR), UV-Vis spectroscopy (UV-Vis), and Field emission scanning electron microscope (FESEM) techniques. XRD analysis confirmed that the synthesized-doped materials retained the wurtzite hexagonal structure with a purity of 99%. Transmission electron microscope (TEM) analysis data reveals the average size of pure ZnO-NPs was found to be 7 nm; after doping the size was found to be increased to 18 nm and 9.55 nm, respectively, for ZnO-W and ZnO-Sb. As per FESEM analysis results, minor morphological changes were observed after doping. The Ultraviolet Differential reflectance spectroscopy UV-DRS study revealed the confirmation of ZnO doping with antimony and tungsten, which exhibited a blue shift. The decrease in the band-gap on doping makes the ZnO-NPs more efficient for photocatalytic applications. The photocatalytic efficiency of pristine and doped ZnO-NPs catalysts for methylene blue photocatalytic degradation (PCD) was analyzed under both UV and solar irradiation. This study analyzed the effect of pH, nano-photocatalyst dose, and initial dye concentration (ICD) on the PCD of MB. The obtained analytical results showed that the ideal conditions for the PCD of MB dye are as follows: pH = 9, the quantity of the nano-photocatalyst used was 300 mg/L, and an initial MB dye dose of 10 ppm. These conditions lead to a PCD of about 91% of the MB dye by using ZnO-Sb nano-photocatalyst on exposure to solar radiation. The reusability study also revealed the stability of nano-photocatalysts. The current research may pave the way for the removal of hazardous dyes from wastewater discharged by many industries.

Aims: The aim of this study is to evaluate the photocatalytic degradation of methylene blue dye on cuprous oxide/graphene nanocomposite. Background: Cuprous oxide (Cu2O) nanoparticles are among the metal oxides that demonstrated photocatalytic activity. However, the stability of Cu2O nanoparticles due to the fast recombination rate of electron/hole pairs remains a significant challenge in their photocatalytic applications. This in turn, leads to mismatching of the effective bandgap separation, tending to reduce the photocatalytic activity of the desired organic waste (MB). To overcome these limitations, graphene has been added to make nanocomposites with cuprous oxides. Objective: In this study, Cu2O/graphene nanocomposite was synthesized and evaluated for its photocatalytic performance of Methylene Blue (MB) dye degradation. Method: Cu2O/graphene nanocomposites were synthesized from graphite powder and copper nitrate using facile sol-gel method. Batch experiments have been conducted to assess the applications of the nanocomposites for MB degradation. Parameters such as contact time, catalyst dosage, and pH of the solution were optimized for maximum MB degradation. The prepared nanocomposites were characterized by using UV-Vis, FTIR, XRD, and SEM. The photocatalytic performance of Cu2O/graphene nanocomposites was compared against Cu2O nanoparticles for cationic MB dye degradation. Results: Cu2O/graphene nanocomposite exhibits higher photocatalytic activity for MB degradation (with a degradation efficiency of 94%) than pure Cu2O nanoparticle (67%). This has been accomplished after 180 min of irradiation under visible light. The kinetics of MB degradation by Cu2O/graphene composites can be demonstrated by the second-order kinetic model. The synthesized nanocomposite can be used for more than three cycles of phtocatalytic MB degradation. Conclusion: This work indicated new insights into Cu2O/graphene nanocomposite as highperformance in photocatalysis to degrade MB, playing a great role in environmental protection in relation to MB dye.

In the present work, Schiff base ligand has been synthesized from synthesized dialdehyde and primary amine. The synthesized ligand and its copper metal complex were characterized by melting point & spectral analysis such as IR, 1HNMR, 13C and GC-MS. In the presence of H2O2 as an oxidising agent the photocatalytic performance of the complex was assessed by the photodegradation of dyes. By carrying spectrophotometrically on irradiation of visible light using Cu(II) metal complex of Schiff base ligand the photocatalytic degradation of Naphthol Blue Black dye (NBB), Rhodamine B (RB) and Methylene Blue (MB) dyes was carried out. The photocatalytic degradation of NBB, RB and MB dyes was carried out with reference to effect of time. The results revealed that Cu-complex of Schiff base ligand is consistent for photocatalysis of these dyes for treatment of authentic effluents. The results show that the optimal dose for maximal degradation of these dyes was found to be 5 mgL-1 of the Cu(II) metal complex. The % degradation of NBB, RB and MB were found to be 55%, 50% and 80% in the visible light irradiation. The % degradation of MB dye was greater as compare to other two dyes. The order of % degradation of three dyes by copper metal complex was found as MB > NBB >RB

Preparation and utilization of Zn-La oxide nanocatalyst as a binary composite for photocatalytic degradation of methylene blue dye: Optimization through RSM-BBD

In the present work, degradation of methylene blue (MB) dye in aqueous solution through H₂O ₂and iron doped g-C₃N₄ (Fe-g-C₃N₄) was studied. The hybrid was fabricated by thermal polymerization with iron (III) nitrate nonahydrate and melamine, and it was characterized by X-ray diffraction, Fourier transform infrared, UV-Vis diffuse reflectance spectrum, X-ray photoelectron spectroscopy, transmission electron microscope and Brunner-Emmet-Teller. The various experimental conditions such as doping amount, a dose of the sample, solution pH, the addition of H₂O₂, and concentration of MB on the degradation of MB dye were optimized. The maximum extent of degradation of methylene blue was obtained at pH 5, doping amount of 2.7 wt% and dose of 0.07 g. The molar ratio of Fe:H₂O₂ is 1:1000 showed 99% of MB (30 mg/L) decolorization over 60 min. The hybrid showed good stability and recyclability after three cycles of use. Photo-Fenton reaction exhibited a higher synergetic effect than the combination of Fenton and photocatalytic process.

Network template-based cross-linked Poly(methyl methacrylate)/tin(IV) oxide nanocomposites for the photocatalytic degradation of MB under UV irradiation

Expanding the light-harvesting range and suppressing the quick recombination of photogenerated charge carriers are of paramount significance in the field of photocatalysis. One possible approach to achieve wide absorption range is to synthesize type-II core/shell heterostructures. In addition, this system also shows great promise for fast separation of charge carriers and low charge recombination rate. Herein, following the surface functionalization method using 3-mercaptopropionic acid (MPA) as a surface functionalizing agent, we report on designing NaNbO3/CdS type-II core/shell heterostructures with an absorption range extending to visible range and explore the opportunity toward degradation of methylene blue (MB) dye as a model pollutant under visible light irradiation. Characterizations including X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), UV-vis diffuse reflectance spectrum (DRS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy support the growth of CdS shell onto NaNbO3 nanorods. The resulting core/shell heterostructures unveiled high surface areas, enhanced light harvesting, and appreciably increased photocatalytic activity toward MB degradation compared to individual counterparts and the photocatalytic standard, Degussa P25, under visible light irradiation. The remarkably enhanced photocatalytic activity of core/shell heterostructures could be interpreted in terms of efficient charge separation owing to core/shell morphology and resulting type-II band alignment between NaNbO3 and CdS, which creates a step-like radial potential favoring the localization of one of the carriers in the core and the other in the shell. A plausible mechanism for the degradation of MB dye over NaNbO3/CdS core/shell heterostructures is also elucidated using active species scavenger studies. Our findings imply that hydroxyl radicals (OH(•)) play a crucial role in dictating the degradation of MB under visible light. This work highlights the importance of core/shell heterostructures in leading toward new paradigms for developing highly efficient and reusable photocatalysts for the destructive oxidation of recalcitrant organic pollutants.

Promising multicatalytic and adsorption capabilities in V2O5/BiVO4 composite pellets for water-cleaning application

The present study focuses on the green synthesis of zinc oxide nanoparticles (ZnO NPs) using a novel Lepidagathis ananthapuramensis (LA) leaf extract and a systematic study on the photocatalytic degradation of methylene blue (MB) dye. The structural, thermal, morphological, optical, and surface area analysis of prepared ZnO NPs were examined using X-ray diffraction (XRD), UV-visible spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis, thermogravimetric analysis (TGA), field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX) and high-resolution transmission electron microscopy (HR-TEM). The LA stabilised ZnO NPs produced NPs with diverse morphologies, low band gap and cost-effective high yield of production. A systematic study has been carried out to determine the crystallinity and crystallite size of ZnO NPs based on the concentration of Zn(NO3)2 precursor, concentration of LA leaf extract, calcination temperature and calcination time. The crystallinity and crystallite size of ZnO NPs were evaluated based on the XRD technique. The photocatalytic activity of ZnO NPs was thoroughly investigated for the degradation of MB dye based on various physicochemical parameters such as reaction time, concentration of catalyst, concentration of precursors, concentration of LA extract, concentration of MB, calcination temperature and calcination time. These systematic photocatalytic studies followed green protocols and provided an excellent photocatalytic efficiency result of 96-98.5% towards the decomposition of MB. Hence, this material can work as a potential candidate for waste water treatment by also degrading other toxic dyes.

Decorating 2D graphene oxides sheets with spherical shaped Fe3O4 for the applications of supercapacitors and sunlight induced sonophotocatalytic degradation of methylene blue dye

The current study focuses on graphene oxide (GO) and its composite with zinc oxide and titanium dioxide nanoparticles to develop a simple nano chemistry-based clean and efficient process for the effective degradation of methylene blue (MB) dye. Graphene oxide composite with zinc oxide and titanium dioxide nanoparticles were fabricated via a thermal coupling process that demonstrates exclusive physiochemical properties. A detailed comparison of the structure, morphology, and surface analysis of synthesized GO and nanocomposites, as well as their electrochemical properties, has been accomplished. By using the degradation of methylene blue (MB) dye the photocatalytic function of nanocomposites was studied. Results reveal that the rate constants of GO, GO-TiO2, and GO-ZnO photocatalysts are 1.06 × 10−3 min−1, 2.56 × 10−3 min−1, and 1.63 × 10−3 min−1 respectively which discloses GO-TiO2 nanocomposite shows maximum degradation of MB dye among both catalysts. The reuse of photocatalyst even after five cycles retained the degradation efficiency of 80, 77, and 49% respectively for GO-TiO2, GO-ZnO, and GO when tested against MB. Hence, as a result, it was determined that these photocatalysts are ideal for the remediation of dye-contaminated wastewater.

This research effort reports the design and development of reduced graphene oxide/zinc ferrite (rGO/ZnFe2O4) nanocomposites for the photo-oxidative degradation of methylene blue (MB) dye. The composite formation of rGO sheets with ZnFe2O4 nanostructures was achieved by a simple process of one- step solvothermal strategy, in which the simultaneous reduction of GO and Zn2+ and Fe3+ ions was achieved. The morphological studies revealed that the surfaces of rGO sheets were densely covered by the 280-nm-sized spherical ZnFe2O4 nanostructures and the average size of nanoparticles that constitutes the sphere was found to be 10 nm. The cubic spinel structure of prepared ZnFe2O4 nanomaterials was confirmed from the diffraction patterns and the nucleation sites exploited for the composite formation of ZnFe2O4 nanostructures with rGO sheets was explored by using FT-IR spectroscopy. The catalytic efficiency of prepared nanostructures toward MB dye degradation in the presence of H2O2 was evaluated in detail, in which rGO/ZnFe2O4 composite exhibited the remarkable catalytic activity toward MB degradation. The complete MB degradation observed at rGO/ZnFe2O4 composite is attributed to the π–π interaction, hydrogen bonding and electrostatic interaction exerted between the rGO/ZnFe2O4 and MB dye and the involved degradation reaction followed a pseudo-first-order kinetics. Thus, the proposed effort has not only provided a simple approach to synthesize the ZnFe2O4-based composites but has also provided a feasible solution for the effective and economically viable approach for the complete degradation of hazardous organic dye.

Metallic nanoparticles are well known of having wide applications in various fields such as, catalysis, electronics, energy, chemistry and medicine due to its unique physico-chemical properties. In this study, nanocatalyst Kyllinga brevifolia-mediated silver nanoparticles (AgNPs) were prepared by reduction of silver nitrate using aqueous extract of Kyllinga brevifolia at different temperature. The formations of AgNPs were monitored using UV-visible spectroscopy. Transmission electron microscope (TEM) results reveal that the AgNPs well dispersed with average particle size are 22.34 and 6.73 nm for synthesized at room temperature and cold temperature respectively. The biomolecules present in the Kyllinga brevifolia aqueous extract responsible for the formation of AgNPs were identified using Fourier transform infrared (FTIR). Our AgNPs performed excellent catalytic activity in degradation of methylene blue (MB) dyes via electron relay effect. MB is toxic to ecological system and also has carcinogenic properties. The AgNPs nanocatalysts synthesized in this study are highly dispersed, quasi-spherical and due to their size in nanoscale, they have shown effectiveness for degradation of MB dyes. More importantly, our AgNPs were prepared using biomolecules as capping and reducing agent, which make our product “greener” than available AgNPs that are commonly prepared using hydrazine and borohydride; which are harmful substances to human and environment. Not only the AgNPs can act as nanocatalyst for degradation of MB, they can also be expected to degrade other types of toxic dyes used in textiles industry.

One-step fabrication of S-scheme ZnO/g-C3N4 composites for enhanced environmental photocatalysis

Reduced graphene oxide (rGO)/bismuth vanadate BiVO4 composites are fabricated with varied rGO amounts (0, 1, 2, and 3 wt%) through the synergetic effects of ultrasonication, photoinduced reduction, and hydrothermal methods, and the materials are tested as tools for sonophotocatalytic methylene blue (MB) dye degradation. The effect of rGO content on the sonophotocatalytic dye degradation capabilities of the composites are explored. Characterization of the proposed materials is done through transmission electron microscopy (TEM), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy as well as scanning electron microscopy. The coexistence of BiVO4 and rGO is confirmed using Raman spectroscopy and XRD. TEM confirms the existence of interfaces between rGO and BiVO4 and XPS affirms the existence of varied elemental oxidation states. In order to investigate the charge carriers transportation, time‐dependent photocurrent responses of BiVO4 and 2 wt%‐ rGO/BiVO4 are done under visible light irradiation. The sonophotocatalytic MB dye degradation in an aqueous medium displays promising enhancement with rGO doping in rGO/BiVO4 composite. The 2 wt%‐ rGO/BiVO4 sample exhibits ≈52% MB dye degradation efficiency as compared to pure BiVO4 (≈25%) in 180 min of the sonophotocatalysis experiment. Phytotoxicity analysis through germination index is done using vigna radiata seeds.