Photocatalytic Activity For Dye Degradation Research Articles

Reduced Work Function in Anatase ⟨101⟩ TiO2 Films Self-Doped by O-Vacancy-Dependent Ti3+ Bonds Controlling the Photocatalytic Dye Degradation Performance.

TiO2 has the proven capability of catalytically decomposing pollutants under light illumination, thereby embracing potential applications in wastewater management. The photocatalytic dye degradation activity is largely controlled by the optical band gap that dictates the extent of electron-hole pair generation via photon absorption, and the recombination kinetics of charges. In this context, the material's work function governs how easily the charge carriers can be transferred at the dye-adsorbed photocatalytically active sites. Accordingly, nanocrystalline TiO2 thin films are grown in the anatase phase with ⟨101⟩ orientation, using RF magnetron sputtering at 200 °C. Besides studying the film's structural morphology, optical band gap, and elemental composition, the electronic properties are extensively investigated. The work function of the material was controlled by varying the O-vacancy-dependent Ti3+ bonding configuration in the network. It has been demonstrated how the photocatalytic methylene blue dye degradation activity of the nanocrystalline TiO2 films of predominantly the anatase phase improves on reducing the sputtering pressure during deposition. At a low deposition pressure of 20 mTorr, a low work function of ∼4.2 eV of the film, resulting from the formation of a Ti3+-bond through the O vacancies in the network, potentially increases its carrier lifetime and delivers the superior photocatalytic activity (∼82.7% dye degradation with a rate constant of k ∼ 0.0073 min-1) via silently facilitating fast electron transfer from the photocatalyst to the dye in the aqueous solution. The higher stoichiometric film prepared at p = 40 mTorr exhibits an inferior photocatalytic activity (∼20.4% dye degradation with a rate constant of k ∼ 0.0009 min-1), as retarded by its higher work function of ∼4.62 eV, despite retaining a relatively low band gap. Thus, without using any heterojunction or extrinsically doped photocatalyst, the dye degradation can be controlled simply by reducing the work function of nanocrystalline TiO2 thin films via controlling the O-vacancy-dependent Ti3+ bonding in its self-doped network.

Biosynthesis of zirconia nanoparticles (ZrO2) by water hyacinth: characterization and its photocatalytic dye degradation activity

Biosynthesis of zirconia nanoparticles (ZrO2) by water hyacinth: characterization and its photocatalytic dye degradation activity

In situ fabrication of Ag decorated porous ZnO photocatalyst via inorganic–organic hybrid transformation for degradation of organic pollutant and bacterial inactivation

In this study, in situ silver (Ag) - porous ZnO photocatalysts were synthesized via solvothermal and post-annealing treatment. The formation of the porous ZnO structure due to the removal of organic moieties from the inorganic–organic hybrids Ag-ZnS(en)0.5 during the annealing process. The optimal Ag–ZnO photocatalyst showed excellent photocatalytic degradation activity, with 95.5% orange II dye and 97.2% bisphenol A (BPA) degradation under visible light conditions. Additionally, the photocatalytic inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) led to a 97% inactivation rate after 2 h under dark conditions. Trapping experiments suggest that the superoxide anion (▪O2−) radicals are the main active species to degrade the organic dye. The improved photocatalytic dye degradation activity and inactivation of bacteria were attributed to the synergistic effect of Ag and porous ZnO structure, increased surface area, and efficiently separated the photoexcited charge carriers. This work could provide an effective strategy for the synthesis of porous structures toward organic pollutant degradation and bacterial inactivation in wastewater.

A new 3D Zn-based MOF with enhanced UV-light promoted photocatalytic activity for dye degradation

A new 3D Zn(II)-based metal-organic framework [(CH3)2NH2]2[Zn5(TTC)4] (1) (H3TTC = 2,2′:6′,2″-terpyridine-4,4′,4″-tricarboxylic acid) has been solvothermally synthesized and characterized. The single crystal X-ray diffraction for 1 indicate that it possess (3,4,4)-connected network with Schläfli symbol (4.84.10)4(84.102)4(4.82). Apart from the structural investigation, the photocatalytic performance of MOF 1 to photo-decompose aqueous solution of model dyes viz. methyl violet (MV), Rhodamin B (Rh B), acetylene carbon black (ACB) and methyl blue (MB) have been examined. The photodecomposition results suggest the Zn(II)-MOF based catalyst exhibits best potential to photodegrade MB dye under UV light irradiation. Effect of photocatalyst dosage and initial MB dye concentration on the photocatalytic properties suggest that the photocatalyst exhibits best activity at 50 mg photocatalyst dosage and 18 ppm of initial dye concentration. The plausible photocatalytic mechanistic pathway of MB dye in the presences of 1 has been established with the aid of trapping experiments and density of states (DOS) calculations.

Preparation and structural investigations of the composite containing lead oxide and graphite as reinforcements and its adsorptive and photocatalytic dye-degradation activity

Water contamination by lead (Pb+2) has attracted enormous research owing to its potential carcinogenic, mutagenic, and toxic effects. Composite membranes are highly efficient, and cost-effective adsorbents for the elimination of heavy metals from water. The present study involves the preparation, characterization, and adsorption properties of a novel (Polyvinyl chloride) PVC/PbO-graphite adsorptive composite membrane (ACM) for the effective removal of Pb+2 ions from water. Four composite membranes were fabricated using PbO-graphite as a filler (5, 10, 15, and 20 %) and PVC as a binder. The physiochemical properties such as water uptake, swelling degree, density, and porosity of the composite membrane were studied. All the mentioned properties were decreased and the adsorptive capacity of the membranes (5.54–9.01 mg/g) declined with increasing filler percentage. It was observed that an increase in the initial concentration, adsorption, time, and pH improved the removal efficiency of the membranes. Maximum adsorption was observed for 5 % filler composite at 80 ppm initial concentration of Pb+2 in 300 min time at a pH of 6. Furthermore, both Langmuir and Freundlich adsorption isotherms were applied to investigate and understand the adsorption ability of the prepared ACMs. These isotherms well explained the adsorption process with an average R2 of 0.9860 and 0.9813 respectively. But the results were best aligned with the Langmuir adsorption mechanism (average R2 = 0.9860). The ACMs were also utilized for the photodegradation of Congo red dye and the ACMs (20 %) degraded about 71 % dye within 50 min.

Synthesis of a novel TiO2/HA/RGO composite material with photocatalytic activity for dye degradation

Titanium dioxide (TiO2) is widely used as photocatalysts in the field of organic wastewater treatment in recent years.In this study, TiO2 is combined with hydroxyapatite (HA) and reduced graphene oxide (RGO) to prepare a novel ternary composite material. And methylene blue(MB) was used as the target pollutant to evaluate the photocatalytic activity of TiO2/HA/RGO. The results show that the introduction of HA and RGO can effectively enhance the catalytic performance of TiO2. Under 120min of simulated sunlight, the composite showed excellent dye removal effect, the removal rate of MB can reach 99.8%, and its degradation rate is 2 times that of TiO2/HA and 7 times that of TiO2. The improvement of the photocatalytic activity of the ternary composite is mainly due to the synergistic effect between TiO2, HA and RGO. This work provides a new idea for the synthesis of practical photocatalysts.

Green Synthesis and Photocatalytic Dye Degradation Activity of CuO Nanoparticles

The degradation of dyes is a difficult task due to their persistent and stable nature; therefore, developing materials with desirable properties to degrade dyes is an important area of research. In the present study, we propose a simple, one-pot mechanochemical approach to synthesize CuO nanoparticles (NPs) using the leaf extract of Seriphidium oliverianum, as a reducing and stabilizing agent. The CuO NPs were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) and Fourier-transform infrared spectroscopy (FTIR). The photocatalytic activity of CuO NPs was monitored using ultraviolet-visible (UV-Vis) spectroscopy. The CuO NPs exhibited high potential for the degradation of water-soluble industrial dyes. The degradation rates for methyl green (MG) and methyl orange (MO) were 65.231% ± 0.242 and 65.078% ± 0.392, respectively. Bio-mechanochemically synthesized CuO NPs proved to be good candidates for efficiently removing dyes from water.

NaBr-Assisted Aqueous Synthesis of Perovskite-Embedded PbBr(OH) Hierarchical Nanostructures for Dye Photodegradation

Halide perovskite nanomaterials have demonstrated promising potential in various fields, including photocatalysis for environmental remediation. However, perovskites’ poor stability toward water makes it difficult to use them for the photocatalytic degradation of organic pollutants in wastewater. Herein, we develop a facile and scalable NaBr-assisted room-temperature aqueous phase procedure for the synthesis of all-inorganic CsPbBr3-embedded PbBr(OH) with controlled hierarchical structures, excellent ambient stability, and strong activity for photocatalytic degradation of dyes (e.g., methyl orange and methylene blue) in simulated organic wastewater. It is exceptional that the added NaBr can complex PbBr2 to form a transparent aqueous solution, enabling the subsequent reaction with the aqueous Cs2CO3 precursor to produce CsPbBr3-embedded PbBr(OH) microflowers and microspheres. The photocatalysis shows that the CsPbBr3-embedded PbBr(OH) photocatalysts exhibit excellent photocatalytic activity for dye degradation under visible-light irradiation, which is significantly stronger than that of commercial TiO2 and some other perovskite-based materials produced using a previously reported method. The excellent stability of the CsPbBr3-embedded PbBr(OH) as a photocatalyst is verified by nine consecutive photocatalytic cycles without a noticeable drop in photodegradation efficiency. This work will shed light on the green synthesis of ultra-stable perovskite-based nanomaterials for photocatalytic degradation of organic pollutants as well as other promising water treatment technology prospects.

Zeolite-Y/g-C3N4 composite with enhanced photocatalytic activity for dye degradation and nitrogen fixation

zeolite-Y/g-C3N4 composite with enhanced photocatalytic activity for dye degradation and nitrogen fixation

Biosynthesis of Silver Nanoparticles, Bioactivity Profiling and Assessment of Photocatalytic Dye Degradation Activity in Punica granatum Juice

Abstract: The textile businesses, particularly dyeing industry is the major polluter in the globe, since the dye manufacturing necessitates a huge quantity of water. Plant mediated nanomaterials has the potential to dramatically accelerate the green revolution in the nanomaterial sectors where environmental contamination is a major problem. In the present study, Punica granatum fruit juice was used as plant source to carry out the green synthesis of AgNPs, reported for the first time. The Punica granatum is rich in polyphenols and flavonoids, responsible in the reduction of Ag+ ions to form AgNPs. The synthesized Punica granatum AgNPs were investigated using UV-vis spectrophotometry, where they had exhibited a visible color change and the maximum absorption peak at 421nm, confirming the formation Punica granatum AgNPs. The SEM analysis had revealed the particles morphology and confirmed the rectangular, spherical and rod structure of the particles. The FTIR analysis had shown the presence of different functional group responsible in the reduction and formation of AgNPs. Further, the dynamic light scattering has depicted the average size to be 228.3nm of the formed AgNPs and the size distribution of the particles in the colloidal solution. The photocatalytic degradation MB dye was carried out using the biosynthesized AgNPs and NaBH4, resulting in 99.4% degradation activity, with an increased concentration of the colloidal Punica granatum AgNPs. The quantitative detection of heavy metal salt solution was performed, with the use of Punica granatum AgNPs as a biosensor, showed its sensitivity towards mercury. The antibacterial activity performed against the following bacteria Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Proteus sp., which had resulted in the formation of a clear zone of inhibition. Punica granatum AgNPs had also showed maximum of 80.94% of DPPH scavenging activity.

Biosynthesis of zirconium nanoparticles (ZrO2 NPs) by Phyllanthus niruri extract: Characterization and its photocatalytic dye degradation activity.

The present study focused on microwave assisted synthesis of zirconium nanoparticles (ZrO2NPs) using leaf extract of Phyllanthus niruri as ecofriendly approach and assessed its antimicrobial and bioremediation efficiency. Visual color transition from yellow to brown indicates the formation of ZrO2NPs which was further substantiated by UV-Visible absorption peak at 300nm. Dynamic Light Scattering (DLS) analysis revealed that the average particle size of ZrO2NPs as 121.5nm with negative zeta potential of -22.6 mv. Scanning electron microscopic analysis showed spherical shaped nanoparticles with an average size of 125.4nm. Results of photocatalytic studies revealed that ZrO2NPs exhibited 74%, 62% and 57%, dye degradation for methyl red, methyl orange, and methyl blue respectively. Antimicrobial studies depicted that ZrO2NPs exhibited bactericidal activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Aspergillus niger at dose of 200μg/mL. Overall results of the present study revealed biogenic synthesis of ZrO2 NPs with potent bioremediation and antimicrobial properties.

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.

Effect of Cu Doping on ZnO Nanoparticles as a Photocatalyst for the Removal of Organic Wastewater.

Environmental problems with chemical and biological water pollution have become a major concern for society. Providing people with safe and affordable water is a grand challenge of the 21st century. The study investigates the photocatalytic degradation capabilities of hydrothermally prepared pure and Cu-doped ZnO nanoparticles (NPs) for the elimination of dye pollutants. A simple, cost-effective hydrothermal process is employed to synthesize the Cu-doped ZnO NPs. The photocatalytic dye degradation activity of the synthesized Cu-doped ZnO NPs is tested by using methylene blue (MB) dye. In addition, the parameters that affect photodegradation efficiency, such as catalyst concentration, starting potential of hydrogen (pH), and dye concentration, were also assessed. The dye degradation is found to be directly proportional to the irradiation time, as 94% of the MB dye is degraded in 2 hrs. Similarly, the dye degradation shows an inverse relation to the MB dye concentration, as the degradation reduced from 94% to 20% when the MB concentration increases from 5 ppm to 80 ppm. The synthesized cost-effective and environmentally friendly Cu-doped ZnO NPs exhibit improved photocatalytic activity against MB dye and can therefore be employed in wastewater treatment materials.

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.

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.

Exploration of grown cobalt-doped zinc oxide nanoparticles and photodegradation of industrial dye

Cobalt-doped and undoped zinc oxide (ZnO) nanoparticles (NPs) with different dopant concentrations were synthesized via the sol-gel method. The structural, morphological, and optical properties of the synthesized NPs were investigated using various techniques. The NPs exhibit a wurtzite structure with an average crystallite size of 20–34 nm. Change in photoluminescence (PL) spectra from dual to single band with dopants suggested decreasing surface state contribution. The PL lifetime of the 430 nm band is too short (< 10 ps), where it is multi-exponential and significantly large for the 550 nm band with a major contribution of 0.3–1.0 ns and a minor contribution of 7–9 ns and 119–126 ns. The photocatalytic performance of NPs was examined by decomposing a Congo red dye under dark, white (LED) light and UV irradiation. Among all the doped NPs, 20% Co2+ doped ZnO shows superior photocatalytic activity for dye degradation with a faster reaction rate constant.

Bio-Construction of CuO Nanoparticles Using Texas Sage Plant Extract for catalytical degradation of Methylene blue Via Photocatalysis

The theme of this research is to highlight the importance of green synthesis for nanomaterials preparation. In citing this statement, herein, we reported bio-synthesis of copper oxide (CuO) nanoparticles by Leucophyllum frutescens leaf extract-mediated reaction along with the study of morphological, optical, structural features and their photocatalytic dye degradation activity of synthesized nanoparticles. The formation of bio-mediated CuO nanoparticles was confirmed by the XRD having crystalline size of 27 nm and monoclinic structure, FTIR presenting absorption band at 673 cm−1. The phase purity was revealed from XRD as there is no extra peak for impurities. The CuO represents the absorption of UV radiations at 380 nm upon UV-DRS studies and band gap energy of 1.48 eV. The morphological studies wereperformed by the FESEM and TEM, both characterized that CuO nanoparticles are spherical in shape. The particle size calculated by particle distribution through FESEM and SEM micrographs was ∼ 25 nm which is in accordance with the crystalline size calculated by XRD. The formation of CuO nanoparticles and phase purity was further validated by the EDX analysis. The metallic existence, phase purity and valency of synthesized nanoparticles confirmed by the XPS. The photocatalytic degradation of methylene blue was studied by CuO under irradiation of visible light. The synthesized CuO degraded the cationic dye in 120 min with the degradation efficiency of 88%. Thus, the proposed work suggests the synthesis of metal oxides nanoparticles via green synthesis is very cost effective and ecofriendly process. The green synthesized CuO nanoparticles are efficient photocatalysts for detection and remediation of organic environmental pollutants in water bodies, presenting their potential towards development of wastewater applications.

Preparation and Enhanced Visible-Light Photo-Catalytic Dye Degradation Activity of NiZY Composites

The photodegradation of malachite green in water was successfully achieved under LED irradiation in the presence of NiO/zeolite photocatalyst. The photocatalyst was prepared by the impregnation method and characterized by XRD, BET, FTIR, DRs, and SEM techniques. The experiments were investigated by varying factors that influence the malachite green removal, such as adsorption, initial dye concentration, catalyst dose, and pH. The characterization results show that the material exhibited a direct optical transition (1.45 eV). The results indicated that NiO/zeolite shows a synergic effect between adsorption/photocatalysis processes.

Preparation of MoS2 and MoO3 Modified TiO2 Composites with Enhanced Visible-light Photocatalytic Activity for Dye Degradation

Preparation of MoS2 and MoO3 Modified TiO2 Composites with Enhanced Visible-light Photocatalytic Activity for Dye Degradation

Co-digestive ripening assisted phase-controlled synthesis of Ag-Sn intermetallic nanoparticles and their dye degradation activity.

The Ag-Sn based system in the nano-size regime is one of the strongest candidates for lead-free solders. Besides, the investigation of several other applications of Ag-Sn nanostructures, especially in catalysis, remains scarce which makes it an interesting system to synthesize and explore its chemistry. In this report, nearly monodisperse ε-Ag3Sn intermetallic nanoparticles were prepared by a simple and convenient solution-based process of co-digestive ripening using Ag and Sn colloids obtained by the solvated metal atom dispersion (SMAD) method. Optimization of the temperature and stoichiometric ratio between the metal elements and the use of an appropriate capping agent are crucial factors to realise phase pure intermetallic nanoparticles. Ag3Sn nanoparticles with a size of 3.8 nm ± 0.6 nm were obtained within 12 h of reaction when tri-n-octylphosphine/tri-n-octylphosphine oxide was used as the capping agent at 205 °C. Interestingly, Ag3Sn@SnOx core-shell nanostructures were obtained by changing the capping agent to palmitic acid. These nanostructures were thoroughly characterized by powder X-ray diffraction, transmission electron microscopy (TEM and STEM-EDS), X-ray photoelectron spectroscopy and optical spectroscopy. Thereafter, Ag and Ag3Sn nanoparticles were utilized for photocatalytic degradation of methylene blue, methyl orange and a mixture of both the dyes.