Activity For Degradation Of Dye Research Articles

Strainer-Separable TiO2 on Halloysite Nanocomposite-Embedded Alginate Capsules with Enhanced Photocatalytic Activity for Degradation of Organic Dyes.

Photocatalysis driven by natural sunlight is an attractive approach to removing pollutants from wastewater. Although TiO2–based photocatalysts using various support nano-materials with high catalytic activity and reusability have been developed for purifying wastewater, the centrifugal separation methods used for the nanocatalysts limit their use for treating large amounts of water. Here, we prepared a TiO2 nano-catalyst supported on a halloysite nanotube (HNT)-encapsulated alginate capsule (TiO2@HNT/Alcap) to recapture the catalysts rapidly without centrifugation. The structure of TiO2@HNT/Alcap was characterized by X-ray diffraction, SEM, and TGA. In our system, the combination of HNTs and alginate capsules (Alcaps) improved the efficiency of adsorption of organic pollutants to TiO2, and their milli = meter scale structure allowed ultra-fast filtering using a strainer. The TiO2@HNT/Alcaps showed ~1.7 times higher adsorption of rhodamine B compared to empty alginate capsules and also showed ~10 and ~6 times higher degradation rate compared to the HNT/Alcaps and TiO2/Alcaps, respectively.

Lignin-derived carbon coated nanoscale zero-valent iron as a novel bifunctional material for efficient removal of Cr(VI) and organic pollutants

Efficient removal of heavy metal ions and organic pollutants in wastewater is of great significance to healthy development of ecosystems. However, the facile preparation of novel functional materials for robust removal of both types of contaminants still remain a challenge. Herein, bifunctional composites derived from nanoscale zero-valent iron (nZVI) coated with lignin-derived carbon (LC) were fabricated via a carbothermal reduction strategy and denoted as Fe0@LC. This hybrid material exhibits superior performance with a maximum heavy metal removal amount of Cr(VI) as high as 575.4 mg/g from aqueous solutions. Notably, the elimination rate of Cr(VI) (100 mg/L) by Fe0@LC could reach up to 100% through adsorption and reduction. Furthermore, the obtained Fe0@LC occurs Fenton-like reactions without additional supply of H2O2 toward effective degradation of organic pollutants, including 100%, 100% and 80% for methylene blue, methyl orange and congo red, respectively. The in-depth experimental and theoretical analyses reveal the synergistic effects between the catalytic Fe0 center and the lignin-derived carbon boost the activity for catalytic degradation of organic dyes and Cr(VI) in the optimized conditions. This work not only provides critical insights into rational design, working mechanism, and application of bio-functional materials for wastewater treatment, but also achieves the goal of “treating waste with waste”.

Proficient route in synthesis of glucose stabilized Ag modified ZnS nanospheres for mechanistic understandings of commercially used dyes degradation

• A facile, one step hydrothermal synthesis method was applied. • Glucose, a bio-molecule was used as a capping agent. • Enhanced sunlight driven photocatalytic dye degradation activity of Ag-ZnS nanospheres than that of ZnS nanospheres. • Charge transfer behavior of ZnS and Ag-ZnS photocatalysts at a low faradic process. • Environmental toxic dyes degradation using photo catalytic process without thermal hazards. The work reported here is based on the one-step facile hydrothermal synthesis of glucose stabilized pristine zinc sulfide (ZnS) nanospheres and silver (Ag) modified ZnS nanospheres. The cubic crystal structure with spherical morphology of as-synthesized nanospheres was confirmed from X-ray diffraction spectroscopy and Field emission scanning electron microscopy, respectively. Blue-shift of optical absorption maxima was studied through UV–Visible absorbance spectroscopy while defect-related emission properties were deduced from the photoluminescence spectroscopy. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopic method were employed for elemental analysis and chemical composition study. Incorporation of Ag into ZnS to form Ag-ZnS nanospheres led to superior photocatalytic efficacy to the photocatalytic mineralization of both rhodamine-B (RhB) and methylene blue (MB) dyes after 120 min of solar irradiation. The respective pseudo-first-order degradation rate constants were 0.0163/min and 0.0225/min for the degradation of RhB and MB dyes, respectively.

Investigation of photo-/electrocatalytic activity of hydrothermal synthesized novel copper ion-modulated bifunctional NiTe2 nanoflakes

Considering the significance of atomic-level modulations into nanoscale architectures have become unique, attractive ideas in the field of sensors and decontamination of organic pollutants from the noxious environment. In this work, a novel bifunctional copper ion-modulated nickel telluride nanoflakes are achieved by a hydrothermal method that is applied as a bifunctional catalyst for sensing the level of L-dopa and removing the organic dye pollutant from the environment. The facile processable Cu-NiTe2 nanoflakes are reported for the first time to enable the semiconductor fabrication as a bifunctional catalyst through a low-cost approach. The cation modulation of copper atoms effectively alters the NiTe2 crystal lattice and yields superior physicochemical nature of bifunctional Cu doped NiTe2 crystal structure. The Cu doped NiTe2 effectively shows the efficient separation of electron-hole pairs and enhanced light-harvesting performance, thus exhibits better photocatalytic activity for the crystal violet dye degradation in visible light radiation within 150 min, and nearly 98% degradation occurs for 5%Cu/NiTe2. The enhanced electrocatalytic sensing of L-dopa is attained for 5% Cu/NiTe2 and the concentration range from 0.9 × 10−6 to 9.9 × 10−6 M and the value of the limit of detection is 0.308 µMµA−1. The 5% Cu/NiTe2 catalyst showed good electrochemical sensing ability towards L-dopa.

Green synthesis and characterization of Ag and Ag/Fe3O4 nanocomposites for antimicrobial effect and rhodamine- B dye degradation

We used a simple two-stage tactic to design and synthesize a magnetically separable catalyst (MSC) Ag/Fe3O4 by combining independently synthesized Fe3O4 and Jatropha curcas root functionalized Ag nanoparticles (NPs) at room temperature. The phase composition of Ag/Fe3O4 NCs was revealed by morphological and structural assessment. The derived Ag/Fe3O4 nanocomposites demonstrated outstanding antimicrobial activity against Gram-negative Pseudomonas aeruginosa comparing to Gram-positive Bacillus subtilis which was determined by the agar well diffusion method. This is due to positively charged surface of metal oxide NPs that may bind to cell membrane. Interestingly, Ag–Fe3O4 NCs demonstrated good photocatalytic activity for organic dye degradation. According to a kinetic study, Ag/Fe3O4 MSC removed 99% of Rhodamine B at a rate constant of 1.89 min−1. The photoelectron could perhaps ultimately collide only with dissolved solids in the substrate to form superoxides, which can damage the dye. Notably, the MSCs reusability was tested using magnetic detachment without sacrificing photocatalytic efficiency. This finding represents a significant breakthrough in the domain of wastewater treatment and biomedicine.

Sequential droplet reactions for surface-bound gold nanocrater array

Femtoliter droplet array exhibit unique stability in contact with a flow. This work demonstrates that reactive femtoliter droplets enables sequential chemical reactions that may be leveraged to simplify the process for producing surface-bound materials. Gold nanocraters (GNCs) are formed on a planar substrate from biphasic reactions between water-insoluble thiol droplets and two aqueous solutions in sequence. The detailed process is that gold precursor solution was injected into a flow chamber hosting a substrate with thiol droplet array in a chamber, followed by injection of a reductant solution. The thiol droplets absorb and weakly bond with gold ions in a precursor solution. Subsequent exposure to a reductant solution accelerates the formation of gold clusters in droplets. The final nanoparticles form GNCs over a large surface area, due to fast formation around the droplet rim. The shape of an individual domain was controlled by the duration of ion absorption in the first step of the sequential reaction. Reacting droplets were followed in time by total internal reflection microscope to understand the reaction process. Morphology and composition of GNCs were characterized by atomic force microscope, SEM, microspectrophotometer, and X-Ray photoelectron spectrometer. We demonstrate that the as-prepared GNCs exhibits stable catalytic activity in degradation of azo dyes for multiple cycles. Compared to many current approaches for producing surface-bound nanomaterials, our approach is based on sequential droplet reactions in a flow-in process. This approach offers unique flexibility in varying independently the reactant concentration and reaction time of each step in the sequential reaction. The synthesized surface-bound catalytic nanomaterials may be applied in water treatment, optical display or fluorescence imaging.

Synthesis of CsPbBr3/CsPb2Br5@silica yolk-shell composite microspheres: precisely controllable structure and improved catalytic activity for dye degradation

Synthesis of CsPbBr3/CsPb2Br5@silica yolk-shell composite microspheres: precisely controllable structure and improved catalytic activity for dye degradation

A Facile Synthesis of MgFe2O4/ZnS Heterojunction with Effectively Enhanced Visible Light Photocatalytic Activity for Degradation of Methylene Blue and Crystal Violet Dyes

A novel n-MgFe2O4–n-ZnS heterojunction catalyst was employed via two step approach for photodegradation of organic dyes such as Methylene Blue (MB) and Crystal Violet (CV) dyes under visible light irradiation. The synthesized MgFe2O4/ZnS NCs were characterized using PXRD, FTIR, UV–Visible spectroscopy, PL and FESEM analysis which reveals the formation of flake like structure with size as to be ~ 50 nm. The photocatalytic experimental result demonstrates that the MgFe2O4/ZnS nanocomposites (NCs) improve photodegradation performance with 98.0% and 91% decomposition of MB and CV dyes within 120 min illumination during simulated visible light irradiation. From the result, MgFe2O4/ZnS NCs has higher photocatalytic performance than that of MgFe2O4, and ZnS due to efficient separation of the photo-induced electron–hole pairs and effective electron–hole generation transfer by the formation of n-MgFe2O4–n-ZnS heterojunction. Hence, photodegradation performance implies that the synthesized MgFe2O4/ZnS NCs can be effectively utilized in waste water purification systems.

Hybrid sonoprecipitation fabrication of magnetic ZnO-GO-Fe3O4 nanophotocatalyst for solar-light-driven degradation of dyes in water

ZnO-GO-Fe3O4 as an effective magnetic nanocomposite in photodegradation of water pollutants is prepared via two step procedure and its photocatalytic activity for organic dyes degradation is investigated. The first step is sonoprecipitation synthesis of ZnO over graphene oxide nanosheet and the second step is addition of Fe3O4 nanoparticles by two methods: precipitation synthesis and solvothermal addition. X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Analysis (EDX), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) Surface Area Analysis and Barrett-Joyner-Halenda (BJH) Pore Size and Volume Analysis, Differential reflectance spectroscopy (DRS), Fourier Transform Infrared spectroscopy (FTIR) and Vibrating-Sample Magnetometer (VSM) techniques are employed to examine the characterization of the nanocomposites. The results display high surface area with mesoporous structure and low energy band gap is obtained for ZnO-GO-Fe3O4 synthesized via solvothermal method. Also, ultrasound irradiation increases the available surface area for photoreaction. The degradation percent of eosin yellow and methylene blue are about 60 and 97%, respectively. The effect of initial pH of solution, the amount of loaded photocatalyst and initial dye concentration are investigated in this research.

Effective fabrication of cellulose nanofibrils supported Pd nanoparticles as a novel nanozyme with peroxidase and oxidase-like activities for efficient dye degradation

Nanozyme-based dye degradation methods are promising for the remediation of water pollution. Though Pd nanoparticles (PdNPs) are known to act as nanozymes, their dye degradation capability has not been investigated. Low nanozyme activities, easy aggregation, difficulties in recovery and reuse are the major challenges in achieving this. For the first time, cellulose nanofibrils-supported PdNPs (PdNPs/PCNF) as a novel nanozyme with good peroxidase and oxidase-mimicking activities and easy recyclability is explored for dye degradation. An efficient and rapid method of PdNPs/PCNF preparation was demonstrated by adjusting the pH and microwave irradiation. Enzyme kinetic studies revealed good kinetic parameters and specific activities of 415 and 277 U/g for peroxidase and oxidase, respectively. PdNPs/PCNF offered 99.64% degradation of methylene blue within 12 min (0.468 min−1) with 0.4 M H2O2 at pH 5.0. Mechanistic studies revealed the involvement of hydroxyl and superoxide radicals. Owing to the network-like structure of PCNF, films and foams were prepared, their dye degradation potentials were compared, and recyclability was tested. Successful degradation of mixed dye solutions and spiked real water samples was achieved and a continuous flow method was demonstrated using a foam-packed column.

Phyto Synthesis of Manganese-Doped Zinc Nanoparticles Using Carica papaya Leaves: Structural Properties and Its Evaluation for Catalytic, Antibacterial and Antioxidant Activities.

The current study aims to synthesize bimetal oxide nanoparticles (zinc and manganese ions) using the carica papaya leaf extract. The crystallite size of the nanoparticle from X-ray diffraction method was found to be 19.23 nm. The nanosheet morphology was established from Scanning Electron Microscopy. Energy-dispersive X-ray diffraction was used to determine the elemental content of the synthesized material. The atomic percentage of Mn and Zn was found to be 15.13 and 26.63. The weight percentage of Mn and Zn was found to be 7.08 and 10.40. From dynamic light scattering analysis, the hydrodynamic diameter and zeta potential was found to be 135.1 nm and −33.36 eV. The 1,1-diphenyl-2-picryl hydroxyl radical, hydroxyl radical, FRAP, and hydrogen peroxide scavenging tests were used to investigate the antioxidant activity of Mn-Zn NPs. Mn-Zn NPs have substantial antioxidant properties. The photocatalytic activity of the Mn-Zn NPs was assessed by their ability to degrade Erichrome black T (87.67%), methyl red dye (78.54%), and methyl orange dye (69.79%). Additionally, it had significant antimicrobial action S. typhi showed a higher zone of inhibition 14.3 ± 0.64 mm. Mn-Zn nanoparticles were utilized as a catalyst for p-nitrophenol reduction. The bimetal oxide Mn-Zn NPs synthesized using C. papaya leaf extract exhibited promising dye degradation activity in wastewater treatment. Thus, the aforementioned approach will be a novel, low cost and ecofriendly approach.

Multifunctional Cu2SnS3 Nanoparticles with Enhanced Photocatalytic Dye Degradation and Antibacterial Activity.

We present a simplistic, ultrafast, and facile hydrothermal deposition of ternary Cu2SnS3 nanoparticles (CTS NPs). The fabricated CTS NPs show superior antimicrobial and photocatalytic activities. In the presence of UV-Visible illumination, methylene blue (MB) dye was studied for photocatalytic dye degradation activity of CTS NPs. Excellent efficiency is shown by incorporating CTS NPs to degrade MB dye. There is a ~95% decrease in the absorbance peak of the dye solution within 120 min. Similarly, CTS NPs tested against three bacterial strains, i.e., B. subtilis, S. aureus, P. vulgaris, and one fungal strain C. albicans, defining the lowest inhibitory concentration and zone of inhibition, revealed greater antimicrobial activity. Hence, it is concluded that the CTS NPs are photocatalytically and antimicrobially active and have potential in biomedicine.

Nanoarchitectonics of vanadium carbide MXenes for separation and catalytic degradation of contaminants

The search of expeditious materials for selective removal of residual contaminants, is an imperative task to the scientific community. In this work, we report the use of vanadium carbide MXenes, for the first time in (i) selective separation of organic dyes, (ii) degradation of pharmaceutical drugs and (iii) degradation of organic dyes. In particular, the exfoliated vanadium carbide (E-V2CTx) MXene shows remarkable selective adsorption of methylene blue dye (within 20 min) in a mixture of different organic dyes. The etched vanadium carbide (V2CTx) MXene shows excellent activity in selective degradation of pharmaceutical drugs (within 2 min) whereas V2AlC MAX phase shows remarkable activity in selective degradation of organic dyes (within 8 min) through advanced oxidation processes. The material shows an adsorption capacity of 16 mg L-1 within 20 min, with an initial concentration of 20 mg L-1. The degradation pathways were analyzed for the degradation of pharmaceutical drugs as well as organic dyes. The materials show remarkable reusability for multiple cycles in oxidative degradation of contaminants. This work provides a path for the design and development of efficient vanadium carbide MXene based materials for wastewater remediation.

Nano Ag0 decorated-silica matrix for the remediation of environmental pollutants: Visible-light driven Cr(VI) photoreduction, photodegradation of organic dye, nanomolar Hg2+ detection, and antimicrobial applications

BackgroundWater contamination with toxic heavy metals and dye colorants causes a harmful effect on all living organisms and affect ecosystem adversely. In this study, nano-Ag0 decorated porous silica matrix conjugated with alanine was investigated for multifunctionality including mercury (Hg2+) detection, visible-light photocatalytic performance for organic dye degradation, Cr(VI) photoreduction and antibacterial activity. MethodHRTEM and XRD verified the anchoring of crystalline Ag0 on silica matrix with devoid of impure phases. SEM and XPS analysis was carried out before and after Hg2+ interaction with nano-Ag0/silica probe to understand the variation in morphology, interactions, chemical states, and intrinsic mechanism. Significant findingsThe LOD of the present probe for the detection of Hg2+ was 12 nM. The Ag0-silica NPs incorporated paper strip and agarose gel was prepared and used for mercury detection by the naked eye. The silica stabilized Ag particles form conjugate with alanine and when it interacts with Hg2+, mercury oxidizes the Ag(0) to Ag(I) by amalgam formation resulting in pale-yellow color changing to colorless. Environmental parameters such as salinity, pH and temperature did not influence Hg2+ detection. In addition, photocatalytic activity of nano-Ag0/silica was tested with cationic methylene blue (MB) dye under visible light irradiation that showed 90.3% degradation. Further, the nano-Ag0/silica exhibited significantly superior Cr(VI) photoreduction activity. In addition, gram positive and gram negative bacterial strains showed higher growth inhibition upon exposure to Ag0-silica NPs.

Taxonomic diversity and predictive metabolic functions of a heavy metal tolerant multiple azo dye degrading bacterial consortium from textile effluents

Direct disposal of industrial dye effluents is a serious environmental menace. The bacterial population selected in response to dye contamination prominently participate in the dye detoxification process. We report multiple azo dye degradation activity of a bacterial consortium developed in the azo dye Congo Red (CR) supplemented medium. Degradation activity was most effective under static condition. Degradation of CR and other dyes at 2000 mg/L concentration ranged from 85 to 97% after 96–120 h except for Amido Black 10B showing 85% decolorization in 24 h. A 16S rRNA gene metagenomic analysis revealed high abundance of Proteobacteria, Bacteroidetes and Firmicutes in the consortium. The dominant bacterial genus were Acinetobacter, Comamonas, Erwinia, Trichococcus, Dysgonomonas, and Citrobacter. PICRUSt based functional analysis of the metagenome sequences predicted abundance of gene and protein families for mineralization of xenobiotic compounds. The predicted genes were mapped on KEGG pathway for construction of CR degradation pathway.

Efficient degradation of toxic mixed dyes through peroxymonosulfate activation by copper/iron nanoparticles loaded on 3D carbon: Synthesis, characterizations, and mechanism

Exploitation of heterogeneous catalysts with high activity, stability and reusability gains increasing worldwide attention due to the tremendous demand for purification of dye wastewater. Copper/iron bimetallic catalysts have been proven to be powerful for persulfate activation to generate reactive radical species. Copper/iron nanoparticles loaded onto porous carbon (Cu/FeNPs@PC) was innovatively designed and used as catalyst for peroxymonosulfate (PMS) activation. Cu/FeNPs@PC manifests high catalytic activity for dye degradation over a wide pH range (4.0–10.0). Under conditions of 0.2 g/L catalyst, PMS 0.15 g/L and pH 4.8, nearly complete degradation (98.4%) of Rhodamine B occurs after 18 min. The rate constant is between 0.0946 and 0.1911 min−1 depending on initial solution pH. Mixed dyes can be efficiently degraded verified by UV–vis spectra and color variation of dye solution. Cu/FeNPs@PC has good stability, magnetism, and reusability for recycling. A synergistic effect of promoting Cu2+/Cu+ and Fe3+/Fe2+ cycle is probability ascribed to the enhanced catalytic activity. The mechanism of catalytic degradation of dyes involves radical species (SO4-• and •OH) and non-radical pathways including 1O2 and mediated electron transfer. This work provides insights into rational design of binary metal catalysts that apply to treatment of dye wastewater.

Composition controllable green synthesis of manganese dioxide nanoparticles using an edible freshwater red alga and its photocatalytic activity towards water soluble toxic dyes

• MnO 2 nanoparticles have been synthesized using a facile and sustainable strategy. • An edible freshwater red alga, Lemanea manipurensis has been used. • The MnO 2 NPs showed enhanced photocatalytic activity. Composition controllable, facile and ambient temperature green synthesis of high purity manganese dioxide (α-MnO 2 ) nanoparticles has been accomplished via reduction of an aqueous KMnO 4 solution using aqueous extract of an edible freshwater red alga, Lemanea manipurensis . The UV–vis spectrum exhibited a broad band centered at 368 nm and the band gap value obtained from the Tauc plot is 2.44 eV. The TEM analysis confirmed the predominant spherical morphology with extensive nanotwinning of the nanoparticles in the size range 6–28 nm. The FE-SEM depicted as spherical agglomerated morphology. The average hydrodynamic diameter of the nanoparticles is found to be ∼115 nm from DLS study. The X-ray diffraction (XRD) spectrum showed sharp intense peaks which correspond to the crystallization of phase-pure α-MnO 2 nanoparticles in tetragonal crystal morphology. The infrared spectroscopy provided clear evidence of the presence of phytomolecules which are responsible for the stabilization of the nanoparticles. The as-synthesized MnO 2 NPs showed excellent photocatalytic activity for degradation of toxic dyes, rhodamine B (RhB), methyl orange (MO) and methylene blue (MB), the degradation rate being 0.06781, 0.04323 and 0.03831 min −1 , respectively. The photocatalyst is readily recoverable and showed excellent stability even after four cycles. The best photocatalytic performance was observed for RhB degradation under scattered sunlight and with 3 mg MnO 2 NPs exhibiting almost complete degradation (92%) within 30 min of exposure time. The photocatalytic degradation for all the dyes followed a pseudo-first order kinetics.

CuCo2O4 photocatalyst for bifunctional applications: Toxic dye degradation and antimicrobial activity

In this paper, an environmentally friendly and facile method for the synthesis of CuCo2O4 nanosheets using deep eutectic solvent was reported. The synthesized CuCo2O4 nanosheets were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), zeta potential research, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) techniques. The CuCo2O4 nanosheets were successfully applied in degradation of organic dyes based on excellent photocatalytic activity. In the photocatalytic system, with 15 mg catalyst, 99.96% Methyl orange, 99.89% Congo red and 99.90% Amaranth (MO: 300 mg L−1, CR:300 mg L−1, AM: 80 mg L−1) in 200 mL solution were degraded in 120 min, respectively. Then, it was proved that removal of dyes was made up of original Langmuir adsorption and first order kinetics. Moreover, the nanomaterial could be reused for six cycles with slight decline of degradation efficiency, proving its high stability. In addition to good photocatalytic activity, the nanomaterial exhibited excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus, achieving a complete bactericidal effect at a concentration of 100 μg mL−1. In conclusion, the as-synthesized nanomaterial had high photocatalytic activity and good antibacterial activity, which was expected to be applied in practical wastewater treatment.

Heterocyclic ligated Co(II), Ni(II), Cu(II) and Zn(II) complexes for efficient photocatalytic and biological applications

We report the synthesis and characterization techniques of mononuclear, heterocyclic ligated Co(II), Ni(II), Cu(II) and Zn(II) complexes. These heterocyclic derivatives, Schiff base (indal-2-abu), are obtained from the reaction between indole-3-carboxaldehyde (indal) and 2-aminobutyric acid (2-abu). From the fundamental analysis, it has been found that the Schiff base with the aforementioned metal ions forms four coordinated mononuclear complexes on 1:2 (metal:ligand) stoichiometry. The structural changes of the complexes are analyzed by FT-IR, electronic and magnetic analysis. The photocatalytic dye degradation activity study of the compounds is performed under UV-light using methylene blue (MB) dye. All the complexes are found to be excellent catalysts for the degradation of MB. Molecular docking is used to recognize the energetic site of the receptor, and attain the finest geometry of the ligand-receptor complex. Furthermore, antimicrobial investigations of Schiff base and its complexes are tested and the results are discussed in detail.

Synthesis of bismuth ferrite by sol-gel auto combustion method: Impact of citric acid concentration on its physicochemical properties

In this study, pure phase BiFeO3 was prepared via a facile sol-gel auto-ignition route using water as a solvent. The influence of citric acid to metal nitrates molar ratio on physicochemical properties of BiFeO3 was also investigated through FTIR, XRD, PL, UV, SEM, and BET analysis. The XRD of the prepared samples revealed the rhombohedral perovskite structures belong to space group R3c. In addition, the BFO2:1 sample showed the smallest crystallite size (42 nm) with the highest purity and recombination rate; while the BFO1:2 sample showed the lowest purity and electron charge recombination rate. The surface areas of the BFO1:1, BFO1:2, and BFO2:1 samples were 1.63, 2.13, and 1.84 m2/g, respectively. Moreover, the bandgaps were found to be 2.17, 2.11, and 2.21 eV for the prepared BFO1:1, BFO1:2, and BFO2:1, respectively. In addition, the appearance of a near-IR band around 814 cm−1 confirms the presence of Bi2Fe4O9 byproduct in the BFO1:2 sample. Finally, SEM revealed that BFO2:1 sample was well-distributed and exhibited uniform morphology, referring to citric acid's ability to stabilize and disperse bismuth ferrite NPs. Furthermore, BFO1:2 sample showed enhanced photocatalytic activity in CR dye degradation than BFO1:1 and BFO2:1 samples, attributed by the increase in the surface area and minimized electron-hole recombination. This strategy eliminates the use of conventional organic solvents and provides an effortless and efficient way to prepare pure BiFeO3 and BiFeO3/Bi2Fe4O9 heterojunction nanocomposite that are potentially applicable for photocatalyst and in solar cell production.