Photocatalytic Degradation Properties Research Articles

ZIF-67-derived Co3O4 micro/nano composite structures for efficient photocatalytic degradation

Flowerlike ZIF-67 micro/nano composite structures were developed by the evolution of ZIF-67 rhombododecahedrons ZIF-67(r) via facile ion-assistant solvothermal treatment. The morphology evolution of ZIF-67 with time-on-stream was studied. The flowerlike Co3O4 micro/nano composite were formed under calcination at relatively low temperature. The flowerlike Co3O4 micro/nano composite structures showed good catalytic properties for photocatalytic degradation of RhB (83.2%), higher than that of Co3O4(p) (69.7%) and Co3O4(r) (75.7%) after 90 min irradiation.

Enhanced Lubrication and Photocatalytic Degradation of Liquid Paraffin by Hollow MoS2 Microspheres.

Nowadays, with the rapid development of environmental protection awareness, the demand for the emergence of a green counterpart of lubricant additive plays a more and more important role in reducing friction and wear as the times require. In this paper, full-hollow and semihollow molybdenum disulfide (MoS2) microspheres were prepared via a hydrothermal method and were characterized and confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). According to our results, both fully hollow and semihollow MoS2 microspheres possessed excellent lubrication-enhancing effects for liquid paraffin (LP), while full-hollow samples after friction provided better photocatalytic degradation properties than semihollow samples after friction. Related analysis indicated that curved layer opened structures with more rim and edge sites, bigger surface area, and narrower band gap made full-hollow MoS2 samples achieve a better photocatalytic level. Thus, it was a sustainable solution for both lubrication-enhancing and photocatalytic degradation functions during different stages of the usage of lubricating oils, which suggests a potential strategy for achieving environmentally friendly developments.

Biogenic Hierarchical MIL-125/TiO2 @SiO2 Derived from Rice Husk and Enhanced Photocatalytic Properties for Dye Degradation.

The hierarchical porous heterostructured MIL-125/TiO2 @SiO2 composites are successfully obtained by biogenic-templated method using rice husk both as biomorphic. The products are characterized by X-ray diffraction, N2 -adsorption-desorption analysis, scanning electron microscopy and Fourier transform infrared spectroscopy. The results reveal that MIL-125/TiO2 @SiO2 possesses a hierarchical porous structure in scale from micrometer to nanometer with high Brunauer-Emmett-Teller (BET) surface area (385.7-902.7 m2 g-1 ). The photocatalytic mechanism was discussed in detail. Meanwhile, the activity of MIL-125/TiO2 @SiO2 for the photocatalytic degradation of rhodamine B in aqueous medium is significantly higher than that of P25. The current work provides some concept and methods in the development of MOF-based photocatalysts.

Enhanced antimicrobial, anti-oxidant applications of green synthesized AgNPs- an acute chronic toxicity study of phenolic azo dyes & study of materials surface using X-ray photoelectron spectroscopy

The drug resistant bacteria and textile contaminations of water cause different sever health problem throughout the world. To overcome this issue, new environmental benign materials and methods are needed. Plant metabolites directed synthesis of nanoparticles is considered eco-friendly and easy in synthesis. Therefore, it was explicit for the synthesis of AgNPs. The prepared AgNPs were evaluated for antibacterial, antioxidant, photo-catalytic and electrochemical degradation properties as well as toxicity of degradation products on aquatic life. X-Ray Photoelectron Spectroscopy (XPS) has been used for analyzing the surface chemistry of prepared AgNPs. The particle size determines the interaction of nanoparticles with pathogens. Both Gram positive and negative bacteria (Escherichia coli and Staphylococcus areous) are used to determine the anti-microbial potency of the green synthesized AgNPs. The synthesized silver nanoparticles showed significant anti-bacterial applications against B. subtilus and S. aureus. The anti-oxidant applications of AgNPs also studied on comparison with vitamin C. The toxicity of the phenolic Azo dyes (PDA) has been studied against Fish, Daphnia and Green Algae. The electrode potential was studied in the electrochemical redox reaction of hydroxy phenol in aqueous media. Simple electrolyte was used to determine the current efficiency. For the stability of electrode multi cyclic voltammetry was also studied during redox reaction, which showed stability under the potential 0.4 to 0.2 V.

Insights into the relationship between the color and photocatalytic property of attapulgite/CdS nanocomposites

Attapulgite/CdS (APT/CdS) nanocomposites were fabricated by hydrothermal decomposition of the cadmium-thiourea complex in the presence of APT. The incorporating of APT not only adjusted the color of APT/CdS nanocomposites and controlled the growth of CdS nanoparticles on the surface of APT without the free agglomeration, but also changed the band-gap energy of nanocomposites to affect their photocatalytic property for degradation of organic dyes. Interestingly, there was a close relationship between the color and the photocatalytic property of APT/CdS nanocomposites. The as-prepared nanocomposites with the optimal color properties exhibited the optimal photocatalytic performance for degradation of methylene blue, methyl violet and congo red within 70 min. The key bridge between the color and the photocatalytic activity was mainly band-gap energy. Therefore, it was presumed that the photocatalytic activity of APT/CdS nanocomposites could be evaluated directly from their color property.

High photodegradation and antibacterial activity of BN–Ag/TiO2 composite nanofibers under visible light

To develop material with good photocatalytic properties for organic compound degradation and bacterial removal, we produced Ag/TiO2 and BN–Ag/TiO2 composite nanofibers that included controlled amounts of boron nitride (BN) nanosheets and silver (Ag).

Enhanced Photocatalytic Degradation Properties of Zinc Oxide Nanoparticles Synthesized by using Turnera subulata Sm.

Enhanced Photocatalytic Degradation Properties of Zinc Oxide Nanoparticles Synthesized by using Turnera subulata Sm.

Cd(II) complex constructed from dipyridyl imine ligand: Design, synthesis and exploration of its photocatalytic degradation properties

Abstract A new Cd(II) complex, obtained by the interaction of 2,2-dimethyl-N,N'-bis((pyridin-2-yl)methylene)propane-1,3-diamine with a Cd(II) ion, is reported. The prepared N4 mononuclear species is structurally characterized by microanalyses, FT-IR, ESI-MS, 1H, 13C- and Dept-135 NMR spectroscopy, and single crystal X-ray diffraction measurements. The electrochemical behavior of the complex is also reported, and exhibits irreversible one electron redox process. Furthermore, the synthesized Cd(II) complex showed significant fluorescence property, and worked as a strong photocatalyst to degrade the Alizarin Red S dye (ARS) under visible light irradiation. The results obtained are excellent showing 82% (approximately) degradation of ARS dye in 30 h.

Synthesis of CuO/Ti-MCM-48 Photocatalyst for the Degradation of Organic Pollutions Under Solar-Simulated Irradiation

CuO loaded on siliceous MCM-48 (Mobil Composition of Matter No.48) containing spatially isolated titania species were prepared in this study. X-ray diffraction, N2-physisorption, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and diffuse reflectance spectroscopy were used to characterize these samples. Results from characterizations showed that the addition of CuO to Ti-MCM-48 could markedly improve the photocatalytic degradation properties of organic pollutions such as rhodamine B and tetracycline hydrochloride under solar-simulated irradiation. The enhanced photocatalytic performance of CuO/Ti-MCM-48 may be due to the formation of p–n heterojunctions between CuO and Ti-MCM-48, resulting in the effective separation of photogenerated electron–hole pairs and the enhanced absorption of visible light. According to the trapping experiment, a possible photocatalytic mechanism of CuO/Ti-MCM-48 composite for the degradation of organic pollutions was proposed. The p–n hetero junctions between Ti-MCM-48 and CuO suppress the photogenerated electron–hole recombination and enhance absorption of visible light, thus improving the photocatalytic degradation of organic pollutions.

Photocatalytic Degradation of Methylene Blue with ZnO Nanoparticles; a Joint Experimental and Theoretical Study

The present work focuses on the photocatalytic degradation and adsorption properties of Methylene Blue (MB) on ZnO nanoparticles from experimental and theoretical points of view. The photoreaction is carried out in a Pyrex photoreactor, equipped with a Krypton lamp. The kinetics of the degradation is explained in terms of Langmuir-Hinshelwood kinetic model. The results show that the pseudofirst-order equation is the model that gives the best fit to the experimental data. The value of the adsorption equilibrium constant is calculated as 0.128 L mg-1. The quantum mechanical cluster approach is used to model the adsorption of MB on the ZnO (0001) facet. Geometrical optimizations and vibrational analysis are performed using density functional theory methods. The calculations show a negative charge transfer from the substrate to the photocatalyst. The calculated value of the adsorption energy is in the range of chemical adsorption energies.

Mesoporous black TiO2-x/Ag nanospheres coupled with g-C3N4 nanosheets as 3D/2D ternary heterojunctions visible light photocatalysts

3D mesoporous black TiO2-x/Ag nanosphere coupled with 2D g-C3N4 sheet ternary heterojunctions are successfully fabricated through a facile evaporation-induced self-assembly (EISA) process and photodeposition method, followed by a mild calcination (350°C) under an argon atmosphere after an in situ solid-state chemical reduction strategy. The resultant mesoporous black TiO2-x/Ag/g-C3N4 ternary heterojunctions with narrow band gap of∼2.27eV possess a relative high specific surface area of∼100m2g−1, main pore size of 6.2nm and the highest visible-light-driven photocatalytic property for degradation of methyl orange (97%) and methylene blue (99%). The apparent reaction rate constants (k) of mesoporous black TiO2-x/Ag/g-C3N4 for methyl orange and methylene blue are∼9 and 11 times higher than that of pristine TiO2. The possible mechanism is proposed, and the excellent photocatalytic property can be ascribed to the introduction of Ti3+ self-doping and g-C3N4, which favor the visible light absorption and the separation of electron-hole pairs, the surface plasma resonance effect of Ag nanoparticle, and the mesoporous networks offer more surface active sites.

Investigating the photocatalytic degradation property of Pt, Pd and Ni nanoparticles-loaded TiO2 nanotubes powder prepared via rapid breakdown anodization

ABSTRACTThe present study was performed to investigate the photocatalytic efficiency of the titania (TiO2) nanotubes (NTs) powder prepared via rapid breakdown anodization sensitized individually with Ni, Pd and Pt metal nanoparticles (NPs). The TiO2 NTs powder had the length of 5–6 μm, with the outer diameter between 20 and 25 nm and the wall thickness of 3–4 nm as observed in the scanning and transmission electron microscopes. The crystal structure analysis employing X-ray diffraction indicated the presence of Pt, Pd and Ni NPs in face-centered cubic phase over the anatase TiO2 NTs powder. The photocatalytic degradation of methylene blue (MB) was carried out with these photocatalysts. As a result, the performance of the 2 at.% Pt-loaded Pt–TiO2 NTs nanocomposite was determined to be superior on comparison to other photocatalysts under the current investigation. Fourier-transform infrared spectra confirmed the absence of any adsorption of MB or degraded products onto the surface of all the photocatalysts. The electron paramagnetic resonance analysis substantiated the e− transfer interaction from the conduction band of TiO2 NTs to Fermi level of Pt NPs has resulted in the better photodegradation process. The possible degradation mechanism using Pt–TiO2 NTs nanocomposites is discussed.

Structural, optical and photocatalytic properties of different metal ions (Cr3+, Co2+, Ni2+, Cu2+ and Zn2+) substituted quaternary perovskites

Perovskites have emerged as interesting photocatalytic materials due to the structural flexibility and narrow band gaps. In present work, effect of metal ion substitution into the lattice of La-Mn perovskite has been studied. The metal doped quaternary perovskites LaMn0.2M0.2Fe0·6O3 (M = Cr3+, Co2+, Ni2+, Cu2+ and Zn2+) has been fabricated using sol-gel autocombustion route. The presence of substituted ions i.e Cr, Co, Ni, Cu and Zn has been confirmed using EDS analysis. Powder XRD technique has been employed for confirming the orthorhombic crystal structure and purity of the substituted perovskites. TEM images indicated the formation of nanoparticles of size range 30–60 nm. The band gaps of quaternary perovskites has been estimated using UV-vis diffused reflectance spectroscopy and were found to be in the range of 2.19–2.51 eV. Both size and narrow band gaps of synthesized quaternary perovskites were suitable for using them as photocatalysts for the degradation of cationic and anionic dyes. Except for chromium ion substitution, all the other metal ions exhibited enhanced photocatalytic properties for dye degradation. The increase in photocatalytic ability can be attributed to the generation of vacancy defects and smaller band gap values resulted from the divalent metal ion substitutions. Among the various metal ion substituted La-Mn perovskites, zinc substituted perovskites exhibited maximum photocatalytic ability.

Magnetic and photocatalytic degradation properties of a 2D (3, 4)-connected framework based on 4,4′-(1H,1′H-2,2′-biimidazole-1,1′-diylbis(methylene))dibenzoic acid

A new Co(II) coordination polymer, namely [Co(L) (1,4-bib)0.5(H2O)2]n (1) (H2L = 4,4′-(1H,1′H-2,2′-biimidazole-1,1′-diylbis(methylene))dibenzoic acid, 1,4-bib = 1,4-bis(1-imidazoly)benzene) have been hydrothermally synthesized. The structure of the title complex was determined by single crystal X-ray diffraction analysis and further characterized by infrared spectrum (IR), elemental analysis and UV–Vis spectrum. Magnetic investigations reveal that the antiferromagnetic interactions exist between the adjacent CoII ions in complex 1. Moreover, complex 1 have high photocatalytic degradation effects on rhodamine B, methylene blue and methyl orange under UV irradiation.

Preparation of magnetically recyclable palygorskite Fe-octacarboxylic acid phthalocyanine nano-composites and their photocatalytic behavior for degradation of Rhodamine B

Novel magnetically recyclable nano-composite photocatalyst (AT/Fe3O4-FeOCAP) was successfully prepared from Fe-octacarboxylic acid phthalocyanine (FeOCAP) and magnetic palygorskite nanoparticle (AT/Fe3O4) by an ultrasonic method. The structure characterizations of the photocatalyst were carried out by Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectra (UV–Vis), Vibrating sample magnetometer (VSM) and X-ray photoelectron spectroscopy (XPS). Moreover, the photocatalytic degradation properties and reusability of the photocatalyst were evaluated using Rhodamine B (RhB) as a model compound. The results of FT-IR, UV–Vis and XPS showed the FeOCAP was successfully introduced onto the surface of the AT/Fe3O4. The nano-composite photocatalyst showed excellent superparamagnetic property, and therefore, could be effectively separated by simply applying an external magnetic field. Photocatalytic activity studies confirmed that the as-prepared photocatalyst had excellent RhB photodegradation property. The degradation percentage of RhB was about 95.6%. The degradation kinetics could be described by the Langmuir-Hinshelwood kinetic model.

Photocatalytic Degradation of an Azo Dye over Novel Monometallic Copper Catalysts Supported on Fibreglass

The monometallic copper catalysts were synthesized by impregnation of fibreglass material covered by TiO2 using magnetron sputtering method at a low temperature plasma technique in vacuum camera. Their physicochemical properties were extensively studied by BET, TPR-H2 and XRD techniques. The photocatalytic properties in degradation of an azo dye were controlled by determination of chemical oxygen demand, total organic carbon and using UV–VIS technique. Fibreglass covered with TiO2 and copper oxides has shown remarkable photocatalytic properties in degradation of Reactive Violet 2 dye. Its stability was increased by its preliminary treatment in HCl. The optimal content of Cu appeared to be 5% in the oxide layer of the catalyst digested in HCl. Kinetic constants determined for the process of the dye photodegradation over Cu2O (5%)/TiO2/fibreglass catalyst were one order higher than for TiO2/fibreglass.

Effect of co-doping and tri-doping with transition metals and a nonmetal on photocatalytic activity in visible light of TiO2 thin film

Mono, co- and tri-doped TiO2 thin films with the transition metals (vanadium and/or chrominium) and a nonmetal (nitrogen) have been fabricated by sol-gel method. X-ray diffraction results clearly reveal anatase crystal structure for all obtained samples and doping with any dopants doesn’t change the anatase phase of TiO2. Compared to TiO2, three types of doped TiO2 thin films exhibit a red-shift in the absorption edge and have much better photocatalytic properties for methylene blue degradation in visible light region. The maximum visible-photocatalytic performance was achieved for tri-doped TiO2 sample. The mechanism for enhancing visible-photocatalytic activity of co-doped and tri-doped TiO2 thin films was also examined.

Solvothermal Synthesis of p-type Cu2ZnSnS4-Based Nanocrystals and Photocatalytic Properties for Degradation of Methylene Blue

The quaternary copper-based chalcogenide Cu2ZnSnS4 (CZTS), have recently arisen as a low-cost and environment-friendly material for photovoltaics and photocatalysis. In this paper, p-type kesterite Cu2ZnSnS4 (CZTS) nanocrystals were synthesized by solvothermal method. X-ray diffraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM) and UV–Vis spectroscopy were used to investigate the structural, morphological and photocatalytic properties of kesterite CZTS nanocrystals. The kesterite CZTS nanocrystals powder were used as a photocatalyst to investigate the degradation rate of methylene blue (MB) under visible-light irradiation. The results show the 62% degradation of methylene blue (MB) within 240 min under visible-light irradiation. Furthermore, Zn was partially doped with Fe, Mn, Co, and Ni. CZTS-based nanocrystals and results reveal that Cu2(Zn0.8Me0.2)SnS4 (Me = Fe, Mn, Co, Ni) could degrade 92, 74, 84 and 89% of MB within 240 min, respectively, indicating promising potential as effective visible-light photocatalysts.

Synthesis of ZnO-CuO/MCM-48 photocatalyst for the degradation of organic pollutions.

The photocatalytic properties of ZnO-CuO catalysts supported on siliceous MCM-48 (Mobil Composition of Matter No. 48) for the degradation of organic pollutions such as methylene blue and salicylic acid under UV light irradiation were investigated. These catalysts were prepared by impregnation of MCM-48 with a mixed aqueous solution of copper acetate and zinc acetate. X-ray diffraction, N2-physisorption, high resolution transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and photoluminescence were used to characterize these samples. Results from characterizations showed that the addition of ZnO to CuO/MCM-48 could markedly improve the photocatalytic degradation properties. The enhanced photocatalytic behaviors of ZnO-CuO/MCM-48 may be due to the formation of p-n heterojunctions between ZnO and CuO, resulting in the effective separation of photogenerated electron-hole pairs. Moreover, the photocatalysts were easily recovered and reused for five cycles without considerable loss of activity.

A novel 2, 6-connected inorganic-organic 3-D open framework based on {As2Mo18} with photocatalytic property and anticancer activity

A new inorganic-organic open framework based on Wells-Dawson arsenomolybdate, {Ag(diz)2}3[{Ag(diz)2}3(As2Mo18O62)]∙H2O (1) (diz=1,2-diazole) has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, UV, XRD, and single-crystal X-ray diffraction. In compound 1, each {As2Mo18} cluster uses six terminal oxygen atoms on 'equator' position to attract peripheral six {Ag(diz)2} linkers, which are further connected by six Dawson clusters located on two different planes via unique equator-to-equator interlaced ways to form a unprecedented 3D network with {812∙123}{8}3 topology. Compound 1 represents the highest covalent connectivity of 3-D Dawson arsenomolybdate, which exhibits merit photocatalytic properties for degradation of refractory dyes Azon Phloxine (AP) under UV light. In addition, compound 1 has a potent inhibition effect on proliferation of Human gastric adenocarcinoma cells (SGC-7901).