Photocatalytic Degradation Properties Research Articles

Gd and Ni co-doped BiFeO3 ferrite/r-GO nanocomposite for photocatalytic environmental remediation applications

Synergistic effects of the co-doping of rare earth and transition metals on the structural, electrical and optical, in multi-ferroic BiFeO3 nanoferrites (NFs) combined with reduced graphene oxide (r-GO) nanosheets, photocatalytic degradation properties can be boosted. In this current study gadolinium and nickel-co-doped Bi1-xGdxFe1-yNiyO3 were synthesised via the tartaric acid-assisted sol-gel method and their composite Bi1-xGdxFe1-yNiyO3/r-GO with 10 % reduced graphene oxide (r-GO) via the ultra-sonication route. Phase and structural investigation were carried out using x-ray diffraction (P-XRD), Raman scattering, and Fourier transform infrared (FTIR) analysis, which confirms the successful fabrication of co-doping in the rhombohedral geometry of the perovskite-type Bi1-xGdxFe1-yNiyO3. Electrical conductivity of the fabricated composite material was observed to increase because of the co-doping and the addition of r-GO. Photoluminescence (PL) spectra of co-doped and r-GO composite material exhibited a decline in PL intensity because optical bandgap energies exhibited narrowing of 1.99 eV and 1.91 eV respectively, which indicates the excellent separation and stabilization of photo-excited charge pairs. Special conduction properties of r-GO nanosheets improved electrical and optical properties, a well-porous nature, large surface area, lower bandgap, and increased dye degradation in the Bi1-xGdxFe1-yNiyO3/r-GO photocatalyst showing excellent photo-degradation of cationic malachite green (M.G.) dye, achieving a degradation efficiency of 96.4 % under natural solar light. Hence, the photocatalyst shows excellent stability where quenching of radicals using selective scavengers shows that OH* radicals and e−/h+ pairs are primarily involved in the mechanism of photo-degradation in a basic pH medium, making the as-fabricated material a potential material for photo-catalytic environmental remediation.

Bifunctional titanium boron-phosphate glass containing Ag nanoparticles for the detection and photocatalysis of organic compounds

This study delves into the structural characterization of a composition comprising Ag-NPs/phosphate plasmonic glass. Additionally, it explores two applications aimed at addressing one of the numerous challenges facing the modern world. The continuous technological progress of society has led to the proliferation of chemicals in natural water sources, posing a significant threat to ecosystems due to their low concentrations, making them difficult to detect and remove. The findings presented herein showcase the potential of Ag-NPs/sodium/titanium-phosphate glasses as a promising solution for detecting and degrading organic pollutants in freshwater. To achieve this, Ag nanoparticles were integrated into the glass surface via the ion exchange method, followed by thermal treatment. Subsequently, the detection of crystal violet solutions, applied dropwise onto the sample surface, was successfully carried out using surface-enhanced Raman spectroscopy, reaching a detection limit as low as 10−6 M. Furthermore, the glass composition demonstrated heterogeneous photocatalytic properties for UV degradation of methylene blue, with enhanced photoactivity attributed to the presence of silver nanoparticles, resulting in a 111 % increase in the kinetic constant compared to unmodified glass. Thus, these newly developed Ag-NPs sodium titanium-phosphate glasses exhibit remarkable bifunctional capabilities, offering improved optical detection and efficient photodegradation of organic molecules.

Preparation of TiO2 composite photocatalyst using amorphous SiO2 microspheres loaded with spent SCR catalysts

The products of S-SCR grinding and alkali treatment (S-SCR-T, primarily consisting of anatase TiO2 with a size less than 20 nm) were utilized as photocatalysts, while SiO2 microspheres (MS-SiO2) were used as carriers. A TiO2 composite photocatalyst (M-Si/SR-Ti) was prepared by wet mechanical grinding. The results demonstrate that in M-Si/SR-Ti, S-SCR-T was uniformly loaded on the MS-SiO2 surface in a well-dispersed state and firmly bonded at the interface with Si–O–Ti bonds. M-Si/SR-Ti prepared under optimized conditions exhibited excellent photocatalytic degradation and recycling properties for methyl orange. The degradation rate of methyl orange solution at 10 ppm for 60 min under UV irradiation was 97%, which was comparable to that of S-SCR-T, and remained unchanged after four cycles of recycling. Compared with S-SCR-T, M-Si/SR-Ti exhibited significantly improved settlement recovery performance in water. The loading of S-SCR-T on the MS-SiO2 surface, which increased the exposure of the nano-TiO2 active site and decreased the energy gap, was the mechanism responsible for improving the photocatalytic performance of M-Si/SR-Ti. This study positively impacted the effort to efficiently utilize and increase the value of S-SCR and reduce the cost of the photocatalyst.

High performance Zn–Al LDH modified forward osmosis membrane with antibacterial, anti-membrane fouling, and photocatalytic degradation ability

Forward osmosis membrane has shown great potential in the fields of seawater desalination and sewage treatment. However, the concentration polarization phenomenon and membrane fouling in the water treatment process greatly reduce the water treatment performance and restrict its application. To address these challenges, we employed a pre-buried seed-in-situ growth method to facilitate the Zn–Al layered double hydroxide (Zn–Al LDH) growth on the thin nanofiber membrane, and use it as the support layer for the preparation of a Zn–Al LDH modified forward osmosis membrane. Studies have shown that the introduction of Zn–Al LDH significantly improves the water treatment efficiency of the forward osmosis membrane (In Al-DS mode, the water flux increased by 87.5 %, up to 50.50 LMH, with a low specific salt flux of 0.13 g L−1). It also exhibits exceptional antibacterial, anti-membrane fouling, and photocatalytic degradation properties. This research presents a novel approach for the development of advanced high-efficiency forward osmosis membranes.

Retraction Note: Influence of Fe doping on the photocatalytic dye degradation and H2 evolution properties of BiVO4 thin films under visible-light irradiation

Retraction Note: Influence of Fe doping on the photocatalytic dye degradation and H2 evolution properties of BiVO4 thin films under visible-light irradiation

Green synthesis of zinc oxide nanoparticles from Allium cepa skin: photo catalytic degradation and antibacterial properties

Green synthesis of zinc oxide nanoparticles from Allium cepa skin: photo catalytic degradation and antibacterial properties

An effective approach to improve photocatalytic dye degradation and electrochemical properties of MoO3 nanoparticles

An effective approach to improve photocatalytic dye degradation and electrochemical properties of MoO3 nanoparticles

Biosynthesis of Ag-Doped CuO Nanoparticles Using Heracleum persicum Extract for Enhanced Antibacterial and Photocatalytic Dye Degradation Properties

Biosynthesis of Ag-Doped CuO Nanoparticles Using Heracleum persicum Extract for Enhanced Antibacterial and Photocatalytic Dye Degradation Properties

La-Doped Sm2Zr2O7/PU-Coated Leather Composites with Enhanced Mechanical Properties and Highly Efficient Photocatalytic Performance.

Flexible La-doped Sm2Zr2O7/polyurethane (PU) coated leather composites were synthesized using a one-step hydrothermal method, with highly efficient photocatalytic degradation properties by coating the La-doped Sm2Zr2O7/PU emulsion onto the leather and drying it. The phase composition and optical properties of the as-prepared photocatalytic material were systematically characterized. The result revealed that La was doped in Sm2Zr2O7 successfully, and the prepared samples still possessed pyrochlore structure. The absorption edge of the prepared samples exhibited a red-shift with the increase in La doping, indicating that La doping could broaden the absorbance range of the La-doped Sm2Zr2O7 materials. The catalytic performance of La-doped Sm2Zr2O7/PU composite emulsion coating on the photocatalytic performance of leather was studied with Congo red solution as the target pollutant. The results showed that the best photocatalytic property was found in the 5% La-doped Sm2Zr2O7 nanomaterial at a concentration of 3 g/L. The resulting 5% La-doped Sm2Zr2O7 nanomaterial exhibited a high specific surface area of 73.5 m2/g. After 40 min of irradiation by a 450 W xenon lamp, the degradation rate of Congo red reached 93%. Moreover, after surface coating, the La-doped Sm2Zr2O7/PU coated leather composites showed obviously improved mechanical properties, as the tensile strength of La-doped Sm2Zr2O7/PU coated leather composites increased from 6.3 to 8.4 MPa. The as-prepared La-doped Sm2Zr2O7/PU coated leather composites with enhanced mechanical properties and highly efficient photocatalytic performance hold promising applications in the treatment of indoor volatile organic compounds.

Enhanced photocatalytic degradation properties of a g-C3N4/BiVO4 heterostructure system induced by surface and interface heterojunctions

Enhanced photocatalytic degradation properties of a g-C3N4/BiVO4 heterostructure system induced by surface and interface heterojunctions

Green synthesis of ZnO-doped cerium oxide nanocomposite using clove extract: enhanced photocatalytic methylene blue degradation and antibacterial properties

Green synthesis of ZnO-doped cerium oxide nanocomposite using clove extract: enhanced photocatalytic methylene blue degradation and antibacterial properties

Highly efficient photocatalytic H2 evolution and degradation properties over NiO/Mn0.5Cd0.5S S-scheme photocatalyst

Well-designed and high-performance S-scheme photocatalysts for the fabrication of green hydrogen are of significant practical significance in solving the environmental and energy crises. In this study, NiO/Mn0.5Cd0.5S S-scheme heterojunctions were triumphantly prepared by electrostatic adsorption, and the formation of energy band bending and internal electric field at the interfacial contact site between NiO and Mn0.5Cd0.5S resulted in a good photogenerated carrier separation ability and enhanced hydrogen reduction performance and Rhodamine B (RhB) degradation performance. The hydrogen production rate of NiO/Mn0.5Cd0.5S S-scheme heterojunction was enhanced to three folds of the unitary Mn0.5Cd0.5S, with an apparent quantum yield (AQY) of 15.28% at 400 nm and a degradation rate of 91.5%. In addition, the NiO/Mn0.5Cd0.5S S-scheme heterojunction has enhanced and sustainable hydrogen precipitation and RhB degradation performance.

Photocatalytic Oxidization Based on TiO2/Au Nanocomposite Film for the Pretreatment of Total Phosphorus (TP)

Phosphorus, an essential rare element in aquatic ecosystems, plays a key role in maintaining ecosystem balance. However, excess phosphorus leads to eutrophication and algal proliferation. To prevent eutrophication, the pretreatment and measuring of the concentration of total phosphorus (TP) is crucial. Compared to conventional TP pretreatment equipment (autoclave), a lab-on-a-chip detection device fabricated using micro-electromechanical system technology and titania (TiO2) as a photocatalyst is more convenient, efficient, and cost-effective. However, the wide bandgap of TiO2 (3.2 eV) limits photocatalytic activity. To address this problem, this paper describes the preparation of a TiO2/Au nanocomposite film using electron-beam evaporation and atomic-layer deposition, based on the introduction of gold film and TiO2 to a quartz substrate. The photocatalytic degradation properties of TiO2/Au nanocomposite films with thicknesses of 1, 2, 3, and 4 nm were assessed using rhodamine B as a pollutant. The experimental results demonstrate that the deposition of gold films with different thicknesses can enhance photocatalytic degradation efficiency through synergetic reactions in the charge separation process on the surface. The optimal photocatalytic efficiency is achieved when the deposition thickness is 2 nm, and it decreases with further increase in the thickness. When the photocatalytic reaction time is 15 min, the lab-on-a-chip (LOC) device with a 2-nm-thick gold layer and autoclave exhibits a similar TP pretreatment performance. Therefore, the proposed LOC device based on photocatalytic technology can address the limitations of conventional autoclave equipment, such as large volumes, long processing times, and high costs, thereby satisfying the growing demand for on-site evaluation.

Efficient methylene blue dye removal using hybrid ZnO/Co/Cs photocatalyst beads

This study highlighted the developments of the hybrid photocatalytic system for wastewater treatment in the textile industry. Chitosan (Cs) and cobalt (Co) were introduced into the conventional catalyst zinc oxide (ZnO) to form the hybrid photocatalyst beads. Four different weight ratios of ZnO/Cs (1:1) and ZnO/Co/Cs (1:1:1, 1:2:1 and 2:1:1) beads were synthesized by the sol-gel method. The photocatalytic degradation properties of the hybrid ZnO/Co/Cs were investigated under visible light irradiation for methylene blue (MB) photodegradation. The study focused on the effect of ZnO/Co/Cs composition ratio, irradiation time and the amount of catalyst loading in the photoreactor for five hours of exposure time. The result was that the 1:1:1 ZnO/Co/Cs photocatalyst beads had the highest degradation rate compared to the other systems. Adding Co to the ZnO/Cs photocatalyst improved the photocatalytic activity by increasing the decolourization percentage of methylene blue

Removal of acid violet 7 from aqueous solution with polymer matrix composite particles by adsorption and photocatalytic decolorization methods: isotherms, kinetics, and thermodynamic studies

ABSTRACT A stable and efficient [m-poly(EGDMA-2-VP)]-TiO2 photocatalyst with magnetically separable UV light activated is synthesised and evaluated for the photodegradation and adsorption of Acid Violet 7 (AV7) dye. The polymer particles synthesised were analysed via Scanning electron microscopy ;(SEM) and energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer – Emmett – Teller (BET) and Electron spin resonance (ESR) techniques. The pH (3, 5, 7 and 9), polymer amount (0.01–0.09 g), initial dyestuff concentration (30, 50, 100, 200, 300, 400 and 500 mg/L), and temperature (277, 293, 318 and 338 K) parameters affecting the adsorption were investigated. The residual dye concentration was read at 517 nm by using a UV-vis spectrophotometer. The best adsorption efficiency (97%) was achieved with 30 mg/L dyestuff solution and 0.01 gram of the polymer at pH 3 at 65°C. The Langmuir isotherm model and the second-order kinetic model were found to agree very well with the experimental data. According to thermodynamic parameters, the adsorption is endothermic and spontaneous. The photocatalytic decolorization was carried out under 395 nm UV light to increase the remaining dyestuffs in the solution. As a result, 99% efficiency was obtained from the removal of dyestuffs from the aqueous solution. The decolorization mechanism is described by The Langmuir-Hinshelwood (L-H) model. The degradation of AV7 has also been confirmed by COD measurements. A slight, gradual decrease (from 93.03% to 75.93%) in the photocatalytic activity is observed during repeated cycles of degradation experiment. Thus, the [m-poly(EGDMA-2-VP)]-TiO2 polymer particles possesses efficient adsorptivity and photocatalytic property for AV7 degradation. The magnetic properties of the polymer particles eliminate the risk of secondary pollution and easy recovery of the catalyst.

Laser-Driven Rapid Synthesis of Metal-Organic Frameworks and Investigation of UV-NIR Optical Absorption, Luminescence, Photocatalytic Degradation, and Gas and Ion Adsorption Properties.

In this study, we designed a platform based on a laser-driven approach for fast, efficient, and controllable MOF synthesis. The laser irradiation method was performed for the first time to synthesize Zn-based MOFs in record production time (approximately one hour) compared to all known MOF production methods with comparable morphology. In addition to well-known structural properties, we revealed that the obtained ZnMOFs have a novel optical response, including photoluminescence behavior in the visible range with nanosecond relaxation time, which is also supported by first-principles calculations. Additionally, photocatalytic degradation of methylene blue with ZnMOF was achieved, degrading the 10 ppm methylene blue (MB) solution 83% during 1 min of irradiation time. The application of laser technology can inspire the development of a novel and competent platform for a fast MOF fabrication process and extend the possible applications of MOFs to miniaturized optoelectronic and photonic devices.

Bioinspired Graphene Aerogels with Hybrid Wettability for Solar-Driven Purification of Complex Wastewater.

Salt deposition and pollutant enrichment greatly hamper efficient and sustainable water production for a solar evaporator. Inspired by the desert beetle, a dual-region hydrophobic graphene/hydrophilic titanium dioxide (TiO2) aerogel (GTA) with internal hydrophilic-hydrophobic hybrid wettability structure is prepared via a facile freeze-drying and thermal reduction method. The evaporator shows adjustable wettability, optimized water content, and a low energy loss in the evaporation process. Simultaneously, the hybrid wetting structure in aerogel subjects salt to a dynamic crystallization-dissolution process to prevent salt deposition. The GTA solar evaporator achieves an evaporation rate of 1.52 kg·m-2·h-1 with a 91.02% efficiency under 1 sun irradiation. Furthermore, GTAs achieve a stable evaporation rate in high salinity brine (25 wt % NaCl) under 1 sun irradiation for 100 h, which could compete well with other most advanced photothermal evaporation materials. Moreover, the synergistic effect of graphene and TiO2 endows GTAs with excellent photocatalytic degradation and self-cleaning properties, which can effectively reduce the enrichment of contaminants on the evaporator. Therefore, GTA evaporators can efficiently and stably obtain clean water from seawater and wastewater, which provides a feasible strategy for the purification of complex wastewater.

Efficient electron transport between NiO/Fe2O3 by loading amorphous carbon improves photocatalytic degradation property

It is crucial to explore effective methods for removing antibiotics from the water environment. Amorphous carbon was introduced to NiO/Fe2O3 nanocomposites by hydrothermal method to synthesize catalysts to degrade antibiotics. The catalysts were characterized by SEM, TEM, XRD, XPS, BET and UV-Vis-DRS. The photocurrent response and electrochemical impedance experiments show that the addition of carbon materials effectively improves the electron migration and transport efficiency between NiO and Fe2O3 and improves the photocatalytic performance. Tetracycline and ciprofloxacin were used as standard contaminants for photocatalytic testing under visible light irradiation. The removal rate of tetracycline (TC, 40 mg/L) was 94% for 80 min and 96% for ciprofloxacin (CIP, 20 mg/L) after 30 min of visible light. The photocatalytic degradation kinetic rate demonstrates the K value of NiO/Fe2O3/C is almost 9.2 times higher than NiO/Fe2O3 for TC, and almost 79 times higher than those observed for CIP.

Superoleophobic TiO2@SSM membranes with antifouling and photocatalytic ability for efficient microbubbles flotation emulsion separation and organic pollutants degradation

In this paper, a stainless steel mesh coated with titanium dioxide (TiO2@SSM) membrane was developed for the separation of stable oil-water emulsions and the degradation of soluble pollutants. The TiO2@SSM membrane showed excellent underwater anti-oil adhesion performance and efficient emulsion separation under gravity (flux of 207.7 L m−2 h−1 and efficiency of 99.58 % for toluene-water emulsion). The emulsion could also be pre-broken by microbubble flotation to enhance the separation performance of the TiO2@SSM membrane (microbubble flotation followed by separation has a flux of 369.3 L m−2 h−1, and efficiency of 99.71 %). And the synergistic operation of separation and microbubble flotation can increase the flux to 451.6 L m−2 h−1. The membrane showed outstanding stability and could be recycled for more than 20 times without significant deterioration, and demonstrated chemical stability for corrosion resistance test (pH 0–14). In addition, the membrane, which is easily modified with silver nanoparticles, achieves improved photocatalytic degradation properties (efficiency from 58.8 % to 88.7 %) and microbubble flotation effect (flux of 613.4 L m−2 h−1). This work provides a rational strategy for the preparation and optimization of inorganic functional membranes for effective emulsion separation and dye degradation, and demonstrates promising applications of the separation and purification in oil-containing sewage and wastewater remediation.

Construction of a series of Co(II)-based coordination polymers with boosted photocatalytic activity for the removal of dye contaminants

When symmetrical V-shaped rigid multicarboxylic acid, 3,5-di(2′,4′-dicarboxyphenyl)benzoic acid (ddb), was selected, five structurally coordination polymers (CPs) have been prepared, namely {[Co2(ddb)(dip)(NMP)(H2O)]·3H2O}n (1), {[Co2(ddb)(dpb)(H2O)]·NMP}n (2), {[Co2(ddb)(dib)(H2O)]·H2O}n (3), {[Co5(ddb)2(H2O)12]·4H2O}n (4) and {[Co3(ddb)(μ3-OH)(bpy)2]}n (5) (dip = 2,6-di(1H-imidazol-1-yl)pyridine; dib = 1,4-di(1H-imidazol-1-yl)benzene; bpy = 2,2′-bipyridine, dpb = 1,1′-(2,5-dimethyl-1,4-phenylene)bis(1H-imidazole) and NMP = N-Methyl-2-pyrrolidone). It was revealed that the flexible frameworks as well as different types of coordination environment of ddb were induced by the solvents and assistant linkers, single crystal X-ray crystallography, and thermogravimetric analysis (TGA), were used to characterize these coordination polymers. The photocatalytic degradation properties of all the structures are investigated against different dye like such as Rhodamine (RhB), methyl orange (MO), methylene blue (MB), methyl violet (MV). When compared to other dyes, the degradation efficiency of MV by 2 was quite high. Furthermore, a photodegradation process was proposed and investigated by radical tapping experiment. The Hirshfeld surfaces study demonstrated that these synthesized coordination polymers contain various forms of intermolecular contacts (C⋯C, H⋯C, H⋯H, and O⋯H).