Excellent Photocatalytic Degradation Ability Research Articles

Broad Spectrum Anti-Fouling, Photocatalytic Antibacterial and Superamphiphobic Coating Fabricated by Composite Electrodeposition Process

Enabling metallic surfaces to possess broad-spectrum self-cleaning functions is one of most active research topics. In this paper, a composite electrodeposition process is adopted to prepare multifunctional self-cleaning metallic surfaces by introducing tungsten trioxide (WO3) nanoparticles and carbon nanotubes (CNTs) into the deposited nickel metal, forming the Ni/nano-WO3/CNTs metal matrix composite (MMC) coating. Preparation parameters and conditions are optimized experimentally in terms of the dispersed phase fraction in the MMC coating and the surface microstructures feature. Wettability, mechanical properties, and self-cleaning functions of the MMC coating are evaluated. It was found that the MMC coating shows a unique micro- & nano-scale dual hierarchical surface structure with overhanging microstructures, being superhydrophilic in its as-plated state and superamphiphobic after it being modified; the as-plated MMC coating exhibits an excellent photocatalytic degradation ability and a broad antibacterial performance for the synergistic decomposition effects of nano-WO3 and CNTs; the modified MMC coating is able to maintain a vigorous superhydrophobicity during thermal shocks, long-distance abrasion, and dozens of time adhesions; both the as-plated and the modified MMC coating are significantly resistant to pollution. The Ni/nano-WO3/CNTs MMC coating surface possesses transferable extreme wettability and thus shows broad-spectrum anti-fouling and antibacterial properties as well as good mechanical durability.

Partially etched Bi2O2CO3 by metal chloride for enhanced reactive oxygen species generation: A tale of two strategies

Light-mediated reactive oxygen species generation with water and oxygen is generally regarded as a mild and efficient way for organic pollutants removal. However, it is highly difficult but desirable to construct a photochemical system with increased reactive oxygen species production. Herein, by using Bi2O2CO3 as a prototype, we devise a simple metal chloride-involved etching method to achieve better light absorption and charge carriers separation in a wide-band-gap semiconductor, thus giving rise to improved molecular oxygen activation. The improved photoinduced reactive oxygen species production is further verified by excellent photocatalytic degradation ability of RhB, TC and BPA under visible and ultraviolet light illumination. In addition, the metal chloride-induced strategies—heterojunction formation and cation doping—significantly affect the dynamics and transfer of carriers, which are advantageous to manipulate one-/two-electron pathway for producing reactive oxygen species.

One‐step synthesis of NiO nano‐photocatalyst by wire explosion process and its application in photocatalytic degradation of Methyl tert‐butyl ether

AbstractThe use of the gasoline additive methyltert‐butyl ether (MTBE) has caused serious concern about groundwater and surface water contamination. In this study, UV light/ NiO nano‐photocatalyst (NiONP) system was firstly used to degradation of MTBE in contaminated water. A low‐cost and environmentally clean exploded‐wire plasma technique based on cheap solid nickel source is developed for preparation of NiONP. Optical, magnetic and physicochemical properties were successfully characterized using DRS, VSM, XRD, SEM, EDX, TEM and BET techniques. The NiONP exhibits excellent photocatalytic degradation ability of MTBE. The degradation process was monitored during the photocatalytic reaction by gas chromatography‐mass spectrometry (GC‐MS). It has been found that MTBE undergoes a series of intermediate step, which leads to form a number of intermediate products, mainly acetone, formic acid and t‐butyl formate (TBF). According to the results of the intermediates determination, a possible pathway degradation of MTBE was also proposed.

Facile fabrication of ternary TiO2-gold nanoparticle-graphene oxide nanocomposites for recyclable surface enhanced Raman scattering

A bi-functional ternary nanocomposite was developed by decorating TiO2 and gold nanoparticles on the reduced graphene oxide nanosheets (TiO2-Au-rGO) for recyclable surface enhanced Raman scattering (SERS) detection. TiO2-Au-rGO nanocomposites have been shown to demonstrate the superior SERS performances, which can be used for highly sensitive detection of rhodamine 6 G with a limit of detection of 1.2 × 10−10 M. Subsequently, the surface can be cleaned automatically by the photocatalytic degradation of the adsorbed analytes into inorganic small molecules under visible light irradiation. This can be attributed to the excellent photocatalytic degradation ability, leading to a recyclable SERS application. After being used four times, their excellent SERS and catalytic performances can still be retained. These results suggest that the TiO2-Au-rGO nanocomposites can provide a new strategy for fabricating recyclable SERS substrates, which are highly desirable for SERS practical application.

Highly porous carbon nitride by supramolecular preassembly of monomers for photocatalytic removal of sulfamethazine under visible light driven

Many organic and inorganic compounds have been developed as visible light driven photocatalysts for environment and energy application. In this work, a metal-free carbon doping–carbon nitride (BCM-C3N4) nanocomposite was synthesized by introducing barbituric acid and cyanuric acid during the polymerization of melamine. The BCM-C3N4 was characterized by structure, porosity, optical performance, and photoelectrochemical properties. Results demonstrated that BCM-C3N4 sample exhibited higher surface area, lower fluorescence intensity, better photocurrent signals and more efficient charge transfer in comparison to pure C3N4. The BCM-C3N4 exhibits excellent photocatalytic degradation ability of sulfamethazine (SMZ) under visible light irradiation. Much superior photocatalytic activity and high pollutant mineralization rate was achieved by BCM-C3N4, where it was 5 times than that of pristine C3N4. The effect of initial SMZ concentrations on photocatalyst was also investigated. Additionally, the trapping experiments and electron spin resonance tests demonstrated that the main active species, such as O2− and h+, could be produced under light irradiation. This work might provide an effective approach to the design of low-cost and highly efficient photocatalysis degradation systems for water treatment.

Sn4+ and La3+ co doped TiO2 nanoparticles and their optical, photocatalytic and antibacterial properties under visible light

Sn4+ and La3+ co-doped TiO2 photocatalytic material with nanoparticle structure have been successfully prepared using SnCl2·2H2O and La(NO3)3·6H2O as precursors. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy and UV–visible spectroscopy have been used to for the characterization of the morphology, crystal structure, particle size and optical properties of the samples. The photocatalytic properties of sample with various amount of La doped TiO2 have been studied by photo degradation of methyl orange (MO) in water under visible light. XRD patterns showed both rutile and anatase phases for 5 mol% of Sn and 5–10 mol% of La. But anatase phase with a little rutile phase was formed for 5 mol%Sn and 10 mol%La. The prepared Sn and La co doped TiO2 photo-catalyst showed optical absorption edge in the visible light area and exhibited excellent photo-catalytic ability for degradation of MO solution under visible irradiation. Antibacterial behavior towards E. coli was then studied under visible irradiation. The synthesized T-5%Sn-10%La powder exhibited superior antibacterial activity under visible irradiation compared to the pure TiO2.

Effect of Cu2+, Si4+ and Zr4+ dopant on structural, optical and photocatalytic properties of titania nanopowders

In this study, different samples of doped TiO2 nanoparticles (5 mol% Cu, 5 mol% Si, 5 mol% Zr) were prepared via simple sol–gel synthesis method by using Zirconyl nitrate hydrate as Zr precursor, Tetra ethoxysilane as Si precursor, Copper nitrate trihydrate as Cu precursor and titanium (IV) butoxide (TBT) as titanium precursor. The effects of doping on the structural, optical, and photo-catalytic properties of nanoparticles were studied by X-ray diffraction (XRD), scanning electron microscopy, TEM and UV–Vis absorption spectroscopy. The XRD showed that the presence of only anatase TiO2 for the undoped and doped titania samples. The prepared doped TiO2 photocatalyst nanoparticles showed optical absorption edge in the visible light region and exhibited excellent photo-catalytic ability for degradation of methyl orange (MO) solution under visible irradiation. Visible photo-catalytic activity of doped TiO2 samples was obviously higher than that of pure TiO2 and reached the maximum at Cu, Si and Zr contents of 5, 5 and 5 mol% (TCSZ sample), based on MO dye decomposition rate.

Sn/Ce co-doping of TiO2 nanoparticles: influence of dopants concentration on optical and structural characteristics

In this study, different samples of Sn and Ce co-doped TiO2 nanoparticles (0.5–1–2 mol% Ce and 1–5–10 mol% Sn) were prepared via simple sol–gel synthesis method by using cerium nitrate hexahydrate as cerium precursor, Tin(II) chloride dehydrate as Tin precursor, and titanium (IV) butoxide (TBT) as titanium precursor. The effects of co-doping on the structural, optical, and photo-catalytic properties of nanoparticles were studied by X-ray diffraction (XRD), Field emission SEM (FE-SEM), TEM and UV–Vis absorption spectroscopy. Surface chemical state of nanoparticle was thoroughly examined by atomic X-ray photoelectron spectroscopy (XPS). XRD results showed that, titania rutile phase formation in ternary system (Ti–Ce–Sn) was inhibited by Ce+4 and promoted by Sn+4 co-doped samples at higher percentage of Sn (5, 10 %). The prepared co-doped TiO2 photocatalyst nanoparticles showed optical absorption edge in the visible light region and exhibited excellent photo-catalytic ability for degradation of methylene blue (MB) solution under visible irradiation. Sn/Ce co-doped TiO2 showed higher catalytic activity under visible light irradiation. Visible photo-catalytic activity of Sn/Ce co-doped TiO2 was obviously higher than that of pure TiO2 and reached the maximum at Ce and Sn contents of 2 and 5 mol%, based on MB dye decomposition rate.

Enhanced photoinduced super-hydrophilicity in sol–gel TiO2 thin films with co-doped Sn/Nb

In this work, Sn and Nb co-doped TiO2 were coated on glazed porcelain substrates via sol–gel dip coating method. Field emission-scanning electron microscopy, transmission electron microscopy, and UV–vis spectrophotometer were used to evaluate thickness and optical properties of the thin films. Surface chemical state of thin films was examined by atomic X-ray photoelectron spectroscopy. Water contact angle on the film surfaces was measured by a contact angle analyzer under solar light irradiation. The optical results indicated that Sn/Nb dopant in TiO2 thin film changed the absorption edge from ultraviolet to visible light and exhibited excellent photo-catalytic ability for degradation of methylene blue solution under solar irradiation. Wettability results indicated that Sn and Nb dopant ions had significant effect on the hydrophilicity property of thin films.

Enhanced photo-catalytic activity of TiO2 nanostructured thin films under solar light by Sn and Nb co-doping

In this study, preparation of Sn and Nb co-doped TiO2 dip-coated thin films on glazed porcelain substrates via sol–gel process have been investigated. The effects of co-doping content on the structural, optical, and photo-catalytic properties of applied thin films have been studied by X-ray diffraction (XRD), field emission SEM (FE-SEM), high resolution transmission electron microscopy (HR-TEM), and UV–Vis absorption spectroscopy. Surface chemical state of thin films was examined by atomic X-ray photoelectron spectroscopy (XPS). XRD results suggest that adding impurities has a great effect on the crystallinity and particle size of TiO2. Titania Rutile phase formation in thin film was promoted by Sn4+ addition but was inhibited by Nb5+ doping. The prepared co-doped TiO2 photo-catalyst films showed optical absorption edge in the visible light area and exhibited excellent photo-catalytic ability for degradation of methylene blue (MB) solution under solar irradiation. Comparison with undoped and Sn or Nb-doped TiO2, codoped TiO2 shows an obviously higher catalytic activity under solar irradiation.

The effect of Sn dopant on crystal structure and photocatalytic behavior of nanostructured titania thin films

In this study, preparation of Sn doped (0–30 mol % Sn) TiO2 dip-coated thin films on glazed porcelain substrates via sol–gel process have been investigated. The effects of Sn content on the structural, optical, and photo-catalytic properties of applied thin films have been studied by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), field emission SEM (FE-SEM), and high resolution transmission electron microscopy (HR-TEM). Surface topography and surface chemical state of thin films were examined by atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). XRD patterns showed an increase in peak intensities of the rutile crystalline phase by increasing the Sn dopant. The prepared Sn-doped TiO2 photo-catalyst films showed optical absorption edge in the visible light area and exhibited excellent photo-catalytic ability for degradation of methylene blue solution under UV irradiation. The result shows that doping an appropriate amount of Sn can effectively improve the photo-catalytic activity of TiO2 thin films, and the optimum dopant amount is found to be 15 mol%. The Sn4+ dopants substituted Ti4+ in the lattice of TiO2 and increased surface oxygen vacancies and the surface hydroxyl groups. TEM results showed small increase in planar spacing (was detected by HR-TEM caused by Sn dopants in titania based crystals).

Fe-doped TiO<sub>2</sub>/SiO<sub>2</sub> Aerogel Microspheres for Visible Light Photocatalysis Degradation of Methylene Blue

In this paper, we present a strategy for the preparation of Fe-doped TiO2/SiO2 aerogel microspheres (Fe-TSAMs) for visible light photocatalysis degradation of methylene blue. A water- in-oil (W/O) emulsion of Span 80–Tween 85/n-heptane–n-butanol/FeCl3-doped TiO2/SiO2 alcoholic sols–formamide was obtained. Wet TiO2/SiO2 gel microspheres were prepared by the sol-gel process in the W/O emulsion, then they were dried at ambient pressure condition to prepare Fe-TSAMs. The Fe-TSAMs were characterized by N2 adsorption and desorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the resultant Fe-TSAMs possess nanoporous network structure comprising TiO2 and SiO2 nanoparticles with diameters of 10-20 nm. The Fe-TSAMs have a mean diameter of about 100 μm, an apparent density of 0.26 g/cm3, a specific surface area of 360 m2/g, a pore volume of 1.77 cm3/g and the most probable pore size of 18.7 nm with the porosity of 87.7%. By using methylene blue as a simulated aqueous pollutant, the visible light photocatalysis properties of the Fe-TSAMs were investigated. The results indicate that low concentration Fe ion doping (5 wt%) could avoid the formation of recombination centers for photo-generated electron/hole pairs. Compared with commercial P25 TiO2 powders, Fe-TSAMs exhibit excellent photocatalytic ability for degradation of methylene blue under visible light region. The Fe-TSAMs could be reclaimed conveniently and the reused Fe-TSAMs also have a good photocatalytic activity.