Application In Photocatalytic Degradation Research Articles

Fabrication of LaCrO3@SiO2 Nanoparticles Supported with Graphene-Oxide for Capacitive Energy Storage and Photocatalytic Degradation Applications

Fabrication of LaCrO3@SiO2 Nanoparticles Supported with Graphene-Oxide for Capacitive Energy Storage and Photocatalytic Degradation Applications

Enhanced Visible Light Photocatalytic Activity of g-C3N4/SiO2@TiO2 Heterojunction Fabricated by Hydrothermal Synthesis

Photocatalysts that can utilize sunlight energy have attracted attention. In this study, g-C3N4 and mesoporous SiO2@TiO2 particles were mixed by hydrothermal synthesis. g-C3N4 was made by a simple method of directly heating melamine. Mesoporous SiO2@TiO2 was prepared using the stover method. These two types of particles were then mixed by hydrothermal synthesis. Hydrothermal synthesis reduced the size of the g-C3N4 particles, and they bound more closely with the TiO2 particles. The degradation of methylene blue dye by visible light was performed to evaluate the organic degradation of the mixed particles. In addition, the mixed particles were formed into a thin film by the spin-coating method. The film's methylene blue degradation performance and the film's power generation performance in a battery were evaluated. The film showed high convenience in the practical application of photocatalytic degradation of organic pollutants because it can be easily separated from the treated liquid after organic matter degradation.

Construction of covalent organic framework nanozymes with photo-enhanced hydrolase activities for colorimetric sensing of organophosphorus nerve agents

Construction of covalent organic frameworks (COFs)-based nanozymes is of great importance for the extensive applications in catalysis and sensing fields. In this work, a two-dimensional COF (DAFB-DCTP COF) was fabricated via Knoevenagel condensation reaction. The integration of catalytically active sites of pyridine groups into the donor-acceptor (D-A) conjugated skeleton endows DAFB-DCTP COF with both hydrolytic and photosensitive properties. The DAFB-DCTP COF can be utilized as an artificial enzyme with selective and photo-enhanced catalytic efficiency, facilitating its application in photocatalytic degradation of hydrolase substrates (p-nitrophenyl acetate, pNPA) by nucleophilic reaction and further realizing colorimetric detection of the nanozyme inhibitor of organophosphorus nerve agent (diethyl cyanophosphonate, DCNP). The distinct color changes could be distinguished by naked eyes even at a low DCNP concentration, and the versatile smartphone analysis featured with reliability and simplicity. For the first time, the COFs' intrinsic hydrolase activity depending on their structural characteristics was investigated in synergy with the photosensitive performance originating from their photoelectric features. The present contribution provides a promising direction towards construction of colorimetric sensing platform based on the regulation of COFs’ non-oxidoreductase activity under visible light irradiation.

Spray coated of newly La-doped SnS2 thin films for photocatalytic degradation application

In the present study, we present a comprehensive investigation on the synthesis and thorough characterization of La (2 and 4 at. %)-doped 2D-SnS2 thin films, which were prepared by a spray-coating method with a clear molecular ink. These thin films were specifically targeted for their potential application in photodegradation. The impact of La doping on the structural, morphological, mechanical, and electrical properties of the thin films was analyzed using a range of appropriate techniques. Additionally, the mechanical properties were assessed through Vickers micro-indentation. The results indicate that the pristine SnS2 films predominantly exhibit a preferred (101) crystal planes, while the introduction of La doping results in the appearance of a secondary Sn2S3 phase. The bandgap of the films was measured to range from 2 eV to 2.22 eV. Moreover, the thermoelectric power analysis revealed that the films exhibit n-type characteristics, and the mechanical properties showed an increase in hardness with La doping. Notably, the photocatalytic degradation rate was found to be 58.2%, 60.27%, and 62.92% for pristine SnS2, La (2 at.%)-SnS2, and La (4 at.%)-SnS2, respectively, when tested against Malachite green dyes under visible light. This enhancement in degradation efficiency can be attributed to the presence of La3+ ions, which promote electron-hole pair generation.

Preparation of Oxygen-Doping Nongraphitic Carbon Nitride via Efficiency Exfoliation for the Application of Photocatalytic Degradation.

E-OLCN photocatalyst was synthesized by oxygen doping of low molecular weight carbon nitride (LCN) with ethanol solvent stripping. The enhanced light absorption, fast electron transport rate, and photogenerated carrier separation efficiency of E-OLCN leads to the excellent photocatalytic degradation performance compared with the original materials. The synergistic effect of oxygen doping and ethanol solvent stripping plays a significant role for the modulation of electronic and structural properties of the prepared catalysts. Methyl orange (MO) and rhodamine B (RhB) are chosen as typical pollutants for the application of photocatalytic degradation. The E-OLCN sample exhibits outstanding photocatalytic degradation performance, where the rate constant k (1 × 10-2 min-1) of E-OLCN (1.68) is 2.9 times than that of O-LCN (0.58) and 8.8 times than that of pristine LCN (0.19) for MO. Moreover, modulated E-OLCN shows good stability after cycling experiments and the activity still achieved 90%. The detailed mechanism for MO degradation was proposed with the technical support of liquid chromatography-mass spectrometry (LC-MS) and electron spin resonance (EPR). The superoxide radical (·O2-) is the main active species and the MO molecule could be decomposition completely.

Synthesis of molybdenum trioxide/graphite carbon nitride heterojunction modified by biomass carbon dots and its application in photocatalytic degradation of methylene blue

Herein, a hexagonal molybdenum trioxide/graphite carbon nitride heterojunction modified by biomass carbon dots was synthesized by a simple one-pot method and successfully applied to the degradation of methylene blue as a photocatalyst. It was confirmed that under optimal compounding conditions, graphite carbon nitride and hexagonal molybdenum trioxide combined to form a heterojunction, and the coupling interface accelerated the charge transfer efficiency. The modification of supplementary biomass carbon dots can improve the photocatalytic activity of the photocatalyst for the degradation of methylene blue. The proposed heterojunction shows better photocatalytic activity than bulk graphite carbon nitride and has good reusability and stability. After irradiation with simulated visible light for 1 h, the degradation rate of methylene blue by the heterojunction reached 67 %, which was 2.7, 2.6 and 5.8 times higher than that of bulk graphite carbon nitride, pure hexagonal molybdenum trioxide and pure carbon dots, respectively.

Green synthesis of zinc oxide nanoparticles from Rhododendron arboreum extract and their potential applications in photocatalytic degradation of cationic dyes malachite green and Fuchsin basic dye

Green synthesis of zinc oxide nanoparticles from Rhododendron arboreum extract and their potential applications in photocatalytic degradation of cationic dyes malachite green and Fuchsin basic dye

Facile synthesis of ZnO/Ag/g-C3N4 nanocomposites for multiple applications in photocatalytic degradation and photoactivated NO2 sensing

It is important to seek effective strategies to fabricate nanomaterials with multi-functionalities in noxious gas detection and poisonous waste treatment. Herein, Ag nanoparticles and g-C3N4 nanosheets co-modified ZnO heterostructure was synthesized via a one-step polymer-network gel method, which is used as both photocatalyst and sensing material. Being a visible-light-driven photocatalyst, the ternary ZnO/Ag/g-C3N4 composite produced 100 % Rhodamine B degradation within 30 min with good cycling stability. Besides, the gas sensor based on ZnO/Ag/g-C3N4 exhibited superb room-temperature sensing performance under neutral light excitation, with a response value of 15.3–5 ppm NO2 and a lower detection limitation. The excellent performance was mainly attributed to the significantly enhanced visible-light absorption as well as effectively suppressed charge recombination because of the synergism between the individual components. Moreover, the formation of g-C3N4 nanosheets during thermal oxidation etching plays a critical role in improving the surface area and enriching the surface oxygen vacancies. Thus, this work provides novel insights for the synthesis and multi-applications of ZnO/Ag/g-C3N4 heterostructure with high performance.

Fabrication of unconventional S-scheme NiAl LDH/Ag6Si2O7 heterojunction photocatalysts: outstanding photocatalytic performance and photocatalytic mechanism for tetracycline degradation

Tetracycline (TC) was photocatalytically degraded using a series of NiAl LDH/Ag6Si2O7 (LAS) catalysts that were manufactured by dotting Ag6Si2O7 (ASO) particles on the surface of NiAl LDH 3D nanospheres. In terms of TC degradation, LAS had the superior photocatalytic performance, and its clearance of TC was 2.85 times and 1.91 times greater than that of pure NiAl LDH and Ag6Si2O7, respectively. The separation of photogenerated electron-hole pairs has been enhanced since the LAS hybrid photocatalyst has more positive sites. Additionally, it was established through the analysis of the photocatalytic mechanism that the principal active participants in the reaction were •O2- and h+. In order to recover the degradation-stage intermediates, two additional TC degradation techniques were supported by LC-MS and 3D EEM assays. Additionally, the LAS photocatalytic substance has outstanding photocatalytic productivity and stability. This study has offered a fresh perspective on how to construct S-scheme heterojunctions, providing a perfect orientation for the application of photocatalytic degradation of contaminants.

Preparation and characterizations of TiO2/ZnO nanohybrid and its application in photocatalytic degradation of tetracycline in wastewater

The photodegradation of tetracycline antibiotics (TC) in an aqueous solution, using the TiO2 nanoparticles, ZnO microparticles, and TiO2/ZnO composite under the UV lamp in a continuous reactor, was performed. The effects of different parameters, such as the initial TC concentration, medium pH, ratio of each photocatalyst, and the flow rate were comprehensively studied. SEM, EDX, and XRD characterization techniques were employed to study the morphology and structure features of the prepared composite. The results revealed that a more significant amount of TC is not easily removed from wastewater. Furthermore, by increasing the pH of the medium to 11, the efficiency of TC degradation was increased, while the amount of removal remained stable at higher pH values. As the flow rate increased up to 190 mL/min, the removal efficiency increased; however, at higher flow rates, lower efficiency was obtained. Moreover, using multivariate analysis and response surface methodology (RSM), a model for removing TC and the effect of experimental parameters on removal efficiency was proposed. The optimal conditions using the RSM method were found to be the reduction efficiency of 78.94 % in pH = 11 (flow rate of 132 mL/min, and TiO2 concentration of 323 mg) and reduction efficiency of 75.89% in pH = 9 (flow rate of 143.19 mL/min and TiO2 concentration of 312.73 mg).

Optoelectronic, photocurrent sensitivity and photocatalytic dye degradation behaviour of spray deposited Cr doped SnO2 thin films

Undoped and SnO2:Cr doped thin films (Cr: 0.25, 0.50, 0.75 and 1 wt%) were deposited by economically home-made spray pyrolysis method. The characteristic behaviour of the deposited films was studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Photoluminescence (PL), Ultraviolet–visible (UV–vis.) spectroscopy, Current-Voltage (I–V) and photocatalytic studies. The XRD analysis confirms the tetragonal rutile structure of SnO2 with predominant orientation along the (2 1 1) plane and the decrease in crystallite size from 48 to 30 nm by Cr-doping. The EDAX and XPS studies reveal the elements and its chemical state of Sn, O and Cr. The SnO2:Cr thin films exhibit an 85% average optical transmittance in the visible region of the electromagnetic spectrum. The SEM micrographs clearly show the well-defined grains with boundaries, and it is evident that grain size drastically reduces from 155 nm to 48 nm as a function of Cr-doping. Photoluminescence analysis confirms the defect-related emission (360 nm, 440 and 490 nm). The photocatalytic activity of all thin films is assessed using malachite green (MG) dye under UV light irradiation. 0.75 wt% Cr-doped SnO2 film shows improved photocatalytic performance (60.37%) than undoped thin film (32.03%). The I–V characteristics of undoped and SnO2:Cr thin films are performed in visible light, showing photo-linear response behaviour. The highest figure of merit (FOM) obtained for SnO2:Cr (0.75 wt%) thin film is 7.07 × 10−6 Ω−1. The obtained values of the FOM and photocatalytic performance are discussed in the context of the suitability of these materials for transparent and conducting window materials in solar cells and photocatalytic degradation applications.

One-Step Hydrothermal Synthesis of Cu2ZnSnS4 Nanoparticles as an Efficient Visible Light Photocatalyst for the Degradation of Congo Red Azo Dye.

A hydrothermal method was successfully employed to synthesize kesterite Cu2ZnSnS4 (CZTS) nanoparticles. X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and optical ultraviolet-visible (UV-vis) spectroscopy were used for characterization of structural, chemical, morphological, and optical properties. XRD results confirmed that a nanocrystalline CZTS phase corresponding to the kesterite structure was formed. Raman analysis confirmed the existence of single pure phase CZTS. XPS results revealed the oxidation states as Cu+, Zn2+, Sn4+, and S2-. FESEM and TEM micrograph images revealed the presence of nanoparticles with average sizes between 7 nm to 60 nm. The synthesized CZTS nanoparticles bandgap was found to be 1.5 eV which is optimal for solar photocatalytic degradation applications. The properties as a semiconductor material were evaluated through the Mott-Schottky analysis. The photocatalytic activity of CZTS has been investigated through photodegradation of Congo red azo dye solution under solar simulation light irradiation, proving to be an excellent photo-catalyst for CR where 90.2% degradation could be achieved in just 60 min. Furthermore, the prepared CZTS was reusable and can be repeatedly used to remove Congo red dye from aqueous solutions.

Effect of Calcination Temperature on Synthesis of g-C3N4 and its Application in Photocatalytic degradation of Methylene Blue Dye

Effect of Calcination Temperature on Synthesis of g-C3N4 and its Application in Photocatalytic degradation of Methylene Blue Dye

Effect of Calcination Temperature on Synthesis of g-C3N4 and its Application in Photocatalytic degradation of Methylene Blue Dye

Effect of Calcination Temperature on Synthesis of g-C3N4 and its Application in Photocatalytic degradation of Methylene Blue Dye

Application of Micro-Arc Discharges during Anodization of Tantalum for Synthesis of Photocatalytic Active Ta2O5 Coatings

Ta2O5 coatings were created using micro-arc discharges (MDs) during anodization on a tantalum substrate in a sodium phosphate electrolyte (10 g/L Na3PO4·10H2O). During the process, the size of MDs increases while the number of MDs decreases. The elements and their ionization states present in MDs were identified using optical emission spectroscopy. The hydrogen Balmer line Hβ shape analysis revealed the presence of two types of MDs, with estimated electron number densities of around 1.1 × 1021 m-3 and 7.3 × 1021 m-3. The effect of MDs duration on surface morphology, phase and chemical composition, optical absorption, and photoluminescent, properties of Ta2O5 coatings, as well as their applications in photocatalytic degradation of methyl orange, were investigated. The created coatings were crystalline and were primarily composed of Ta2O5 orthorhombic phase. Since Ta2O5 coatings feature strong absorption in the ultraviolet light region below 320 nm, their photocatalytic activity is very high and increases with the time of the MDs process. This was associated with an increase of oxygen vacancy defects in coatings formed during the MDs, which was confirmed by photoluminescent measurements. The photocatalytic activity after 8 h of irradiation was around 69%, 74%, 80%, and 88% for Ta2O5 coatings created after 3 min, 5 min, 10 min, and 15 min, respectively.

Green Synthesis of Silver Nanoparticles Using Dry Leaf Extract of Ricinus communis and Its Application in Photocatalytic Degradation of Carcinogenic Dyes and Antifungal Studies

Green Synthesis of Silver Nanoparticles Using Dry Leaf Extract of Ricinus communis and Its Application in Photocatalytic Degradation of Carcinogenic Dyes and Antifungal Studies

Visible-light-induced activation of peroxymonosulfate by N-CuMe2Pc nanorods decorated on siloxene sheets for degradation of Rhodamine B

Exploring highly efficient photocatalysts is critical for integration of photocatalysis and peroxymonosulfate (PMS) activation. Herein, N-CuMe2Pc/Siloxene nanocomposites were fabricated by immobilizing the N-CuMe2Pc nanorods onto the surface of ultrathin Siloxene nanosheets to activate PMS for efficient photodegradation of (Rhodamine B) RhB. The prepared nanocomposites possess excellent photoabsorption capability and separation efficiency of photogenerated carriers. As expected, the nanocomposites exhibit superior catalytic activity and stability in PMS activation toward RhB photodegradation with highest removal efficiency of 95.3%, which is higher than that of Siloxene and N-CuMe2Pc. The active species in photocatalytic process and degradation pathways were determined through radical quenching studies. The reaction mechanism was systematically illustrated based on the intermediates detection and band structures. This study provides an experimental basis for further understanding of the photocatalytic oxidation behavior of metal phthalocyanine modified two-dimensional semiconductor materials, and is helpful to promote the research and application of photocatalytic degradation of refractory organic pollutants.

Environmentally Benign Nanoparticles for the Photocatalytic Degradation of Pharmaceutical Drugs

A rapid rise in industrialization has led to the release of pharmaceutical pollutants into water bodies, rendering water inappropriate for consumption by humans and animals, challenging our efforts to achieve the clean water sustainable development goal. These pharmaceutical pollutants include antibiotics, anticancer drugs, antidepressants, etc., which are highly stable and persistent in water, in addition to being harmful to life. At times, the secondary pollutant that is formed after degradation is more potent than the parent drug. Conventional water purification methods cannot completely remove these pollutants. Hence, efficient and robust methods are required to degrade pharmaceutical waste. Photocatalytic degradation of drugs is deemed an efficient and effective method for environmental remediation, along with recovery of photocatalysts, which are important for recycling and sustainable use. Herein, we present the synthesis of nanoparticles (NPs) and their application for photocatalytic degradation of pharmaceutical waste as a preferred water treatment method. Additionally, green synthesis of photocatalytic nanomaterials offers the benefit of avoiding secondary pollution. The green synthesis of NPs is employed by using plant extracts that offer a number of metabolites as reducing agents or capping agents, as well as the use of microbes as green nanofactories to tackle the issue of water cleanliness with respect to pharmaceutical waste. Despite regulations concerning drug disposal, some underdeveloped countries do not enforce and practice these guidelines in letter and spirit. Hence, the current work presenting a promising water cleanliness method is expected to contribute to the assurance of strict policy compliance and enforcement, resulting in the resolution of the health concerns with respect to hazardous pharmaceutical waste disposal in water bodies.

A study on structural anisotropy and surface hydroxylation of nanorod units of triphasemesoporous TiO2 for its application in photocatalytic degradation of organic pollutants in wastewater

A study on structural anisotropy and surface hydroxylation of nanorod units of triphasemesoporous TiO2 for its application in photocatalytic degradation of organic pollutants in wastewater

Bio-synthesis of TiO2 using grape leaves extract and its application for photocatalytic degradation of ibuprofen from aqueous solution

ABSTRACT In this study, titanium oxide nanoparticle was fabricated using the extract of grape leaves (referred asGL-TiO2 NPs), using the green synthesis process, and then explores its ability for photodegradation of ibuprofen (IBU) under UV light in the batch system. UV-Vis, BET, FTIR, XRD, and SEM-EDX tests were made to identify the catalyst’s structure and shape. Moreover, the effects of different operating parameters, specifically pH of (3, 5, 7, and 9), IBU concentration (10, 20, 40, and 80) mg/L, GL-TiO2 concentrations (15, 30, and 60) mg/L, H2O2 (100, 300, and 500) mg/L, and contact time were studied. According to the results, the synthetic TiO2 NPs have a spherical shape and 39.608 m2/g of BET surface area. In addition, the findings showed that the removal efficiency reached 92.32% under optimum conditions of 5, 10, 30, 300 mg/L, and 150 min, respectively. In addition, the reaction followed a first-order kinetics model with R 2 > 97. According to the finding of this study, GL-TiO2 NPs has an acceptable efficiency in the elimination of IBU, as their relatively simple synthesis, could be a suitable catalyst for the degradation and elimination of pharmaceutical residues.