Visible Light-induced Degradation Research Articles

Optimizing photocatalytic and supercapacitive performance by β-Bi2O3@BiFeO3 modification with PVDF polymer based nanocomposites

The PVDF (Poly-Vinyl-difloride) membrane modified with Bismuth oxide (β-Bi2O3)/Bismuth Ferrite (BiFeO3) p-n heterojunction synthesized via hydrothermal process to explore its energy storage and conversion applications. The PVDF-Bi2O3/BiFeO3 nanocomposites (NCs) prepared in this study were subjected to analysis using PXRD, FTIR, UV-Vis DRS, FE-SEM with EDX, TEM, and transient photocurrent response techniques, individually. The as-prepared materials were evaluated for their photocatalytic performance in the visible light-induced degradation of Methylene Blue (MB) and Rhodamine-B (RhB) dyes. The photocatalytic performance demonstrates degradation efficiencies of 95% for MB dye and 83% for RhB dye when utilizing the PVDF-β-Bi2O3@BiFeO3 nanocatalyst. The enhancement in the photocatalytic performance of the PVDF-Bi2O3/BiFeO3 heterojunction was a result of improved visible light absorption, suppression of photogenerated electron-hole pair recombination, accelerated separation and migration of photogenerated charges. The capacitance behavior of PVDF-β-Bi2O3@BiFeO3 is significantly higher than β-Bi2O3@BiFeO3 in 3 M KOH solution which has specific capacitance of 300 F g−1at 1 A g−1 of current density and fabricated a symmetric device has10.08 Wh kg−1 and 999.39 W kg−1 specific energy and specific power at 0.5 A g−1 of current density with the 88.7% of capacitance retention and 94.12% of coulombic efficiency up to 10000 cycles.

Visible light-induced PET degradation using red CdxZn1−xSeyS1−y quantum dots capped with two different ligands under varying pH conditions

Poly(ethylene terephthalate) (PET) is a commonly used plastic material that poses a significant environmental challenge due to its resistance to degradation. In this study, we explored the potential of red quantum dots (QDs) capped with two different ligands for PET degradation under varying pH conditions. Herein, we have selected band-engineered gradient-alloyed QDs CdxZn1−xSeyS1−y, which were prepared by controlling the stoichiometry of the composition manipulation. The QDs possess the funnel-shaped energy level, which leads a superior electron-hole separation ability and wider photon capture range and enhances their performance in various applications. The QDs can be tuned for light-harvesting range, charge carrier separation ability, and redox reactivity through adjustments in composition and size. By conducting reactions under different conditions, we obtained various products, with CO being the primary product. Despite the significant challenge posed by plastic pollution, our study offers a novel approach for plastic photodegradation.

Bi2O3/ZnO heterostructured semiconductor nanocomposites: synthesis, characterization and its visible light-induced degradation of methylene blue dye

Abstract In this study, we describe the creation of linked semiconductor nanomaterials, which represents a significant development for photocatalytic applications. A Bi2O3–ZnO hetrostructured thin film was created using the SILAR-CBD deposition technique. In comparison to pure ZnO and Bi2O3, the produced heterostructured thin film showed greater photocatalytic (PCD) activity for the degradation of methylene blue (MB) dye under UV light. The formation of Bi2O3 (monoclinic lattice phase) and ZnO (hexagonal wurtzite phase) are the heterostructured nanomaterials that were generated, according to a powder XRD inspection. An image taken with HR-TEM demonstrates the mixing of nanoparticles and nanorod formations in the Bi2O3/ZnO. The vectorial movement of electrons (e−) and holes (h+) between ZnO and Bi2O3 is responsible for the boosted photocatalytic efficiency, which is in turn, accountable for the enhanced photocatalytic activities.

In2S3 incorporated into CO32−@Ni/Fe/Zn trimetallic LDH as a bi-functional novel nanomaterial for enzymatic urea sensing and removal of sulfur-containing pharmaceutical from aqueous streams

The Ni/Fe/Zn trimetallic LDH intercalated with carbonate ions grown over In2S3 nanoparticles to form a novel In2S3/LDH nanocomposite fabricated with the combined efforts of the solvothermal and in-situ precipitation processes, as well as its enzymatic sensing and visible light-induced degradation ability, were thoroughly investigated in this study. The urease-immobilized In2S3/LDH/ITO electrode showed high-performance electrochemical sensing over a wide range of 1–240 µM with a lower limit of detection (LOD) of 0.246 µM and enhanced sensitivity of 2.29 × 10−7 A μM−1 cm−2 in phosphate buffer solution (50 mM, pH 7.5, 0.9 % NaCl) at a scan rate of 50 mV s−1. The fabricated electrode was reusable for up to 15 scans and demonstrated very high selectivity towards urea, as it showed an insignificant change in current, even in the introduction of various interferences. Furthermore, the synthesized In2S3/LDH nanocomposite demonstrated enhanced photocatalytic ability for degradation of 15 ppm of emerging sulfur-containing pollutant pantoprazole with an impressive efficiency of 98.25 ± 1.51 % in 35 min of visible light irradiation, with a high rate constant of 0.1 min−1. The H2O2-assisted AOP process showed improved COD removal of up to 87.31 ± 1.43 %, with high stability and reusability up to 7 consecutive cycles. Moreover, the as-prepared In2S3/LDH nanocomposite also showed significant degradation of other emerging pollutants with a more than 70 % degradation efficiency. As a result, this composite is a potential electrocatalyst for urea sensors in practical analysis, and it also has outstanding photodegradation of pantoprazole under visible light irradiation.

Biogenic Synthesis, Characterization of Cerium Oxide Nano Particles using <i>Perioria pinnatum</i> Leaf Extract and Its Applications

The biogenic method of synthesis of metal oxide nanoparticles is the recent advances development in nanotechnology, and cerium oxide (CeO2) nanoparticles (NPs), in particular, are advantageous due to their remarkable properties. In this report, we discuss the results of Cerium oxide NPs synthesized by solution-combustion method using “Perioria pinnatum” leaf extract as a reducing and stabilizing agent. The structurally spherical shaped CeO2 NPs with 12 nm crystal size were synthesized and further characterized by powder X-ray diffraction analysis (PXRD), Fourier transforms infrared spectroscopy (FT-IR), and Scanning electron microscopy (SEM) and with Energy dispersive X-ray (EDX) analysis. XRD pattern confirmed the formation of CeO2 NPs with FCC structure. Further, green synthesized CeO2 nanoparticles were assessed for their in-vitro antioxidant activity, visible light-induced dye degradation property against methylene blue, and in electrical cells modified with CeO2 NPs that could electrochemically sense Dopamine (DA) up to 11 µM.

CuS Nanoparticles Modified ZnO/CdS Dual Direct Z-type Heterostructure Nanocomposite for Efficient Visible-Light Photocatalytic Degradation RhB

The low-temperature hydrothermal and water bath methods are used to manufacture CuS@ZnO/CdS catalyst. The Rhodamine B degradation rate constant of CuS@ZnO/CdS is around 1.53 × 10−2 min−1, which is 3.9 times greater than that of ZnO. The coupling of CdS and loading of CuS onto ZnO surfaces were evaluated using XRD, SEM, TEM, and XPS. SEM demonstrated that 5 mg of CdS was the most effective in controlling the shape of ZnO nanoflakes. Ultraviolet-visible absorption (UV–vis) and Photoluminescence (PL) spectra reveal that CdS and CuS decreased the bandgap of ZnO and boosted its ability to absorb visible light. Transient photocurrent response (TPR) and electrochemical impedance spectra (EIS) display that CdS and CuS facilitate the quick separation of photoexcited carriers in ZnO. Notably, the optimal weight ratio of CuS was determined to be 15%, since excessive amounts of CuS would operate as recombination centers and cover active sites. Additionally, the dual Z-scheme carriers movement mechanism was proposed using sacrificed agent experiments, and TOC analyzed the mineralization rate of RhB after degradation. In this study, CuS@ZnO/CdS photocatalyst degraded RhB nearly 99% in 80 min, which is superior to the earlier photocatalysts. Therefore, this article holds great significance in the practical application of metal chalcogenide-modified ZnO-based photocatalysts with superior visible light-induced degradation performance in environmental purification.

Visible Light-Induced Oxidative Degradation of Chloramphenicol by Iron-Containing Ceramic-Metal Composites

Visible Light-Induced Oxidative Degradation of Chloramphenicol by Iron-Containing Ceramic-Metal Composites

Visible light-induced degradation of organic dyes by niobium tellurium oxides ANbTeO6 (A = Rb, Cs) with β-pyrochlore structure

Niobium tellurium oxides ANbTeO6 (A = Rb, Cs) with β-pyrochlore structure were prepared via a solid-state reaction followed by ball milling. The photocatalytic activity of the compounds was investigated in the degradation of organic dyes under ultraviolet and visible light. The nanosized RbNbTeO6 demonstrated the highest photocatalytic activity in the degradation of methylene blue, which could be attributed to much more efficient adsorption of the dye onto the surface. It was found that the photocatalytic activity of the nanosized RbNbTeO6 photocatalyst is much higher than that of its structural analogues. This work presents a novel photocatalyst with high performance for the degradation of cationic dyes, and it affords a prototype to efficiently utilize solar energy.

New approach for the synthesis of Ag3PO4-graphene photocatalysts

A facile and effective plasma sputtering method for the preparation of a visible light active photocatalyst - rhombic dodecahedral silver phosphate Ag3PO4 covered with nanographene (Ag3PO4-GR) with improved stability has been developed. Proposed method allows for the usage of readily available materials for nanographene sputtering and for easy scaling-up. The stability improvement, confirmed by visible light-induced phenol degradation experiment, could be attributed to the synergistic effect of the silver phosphate particles and graphene material allowing for migration of metallic silver nanoparticles from semiconductor's surface to graphene body keeping the semiconductors surface “silver free”. Also due to its conductive properties, nanographene may additionally be preventing electron-hole recombination and metallic silver formation.

Visible light-induced degradation of propranolol with peroxymonosulfate as an oxidant and a radical precursor

A cost-effective method for the degradation of propranolol, which does not require a high amount of energy and expensive materials/chemicals, was developed. The degradation of propranolol by peroxymonosulfate (PMS) was slow under dark conditions. However, visible-light irradiation significantly accelerated the PMS-mediated propranolol degradation (degradation efficiency after 2 h = 71.0% under visible light vs. 9.7% under dark conditions), although neither PMS nor propranolol absorbed the visible light. The degradation products generated from the oxidation of propranolol by PMS absorb visible light, which facilitates the photochemical reduction of PMS and oxygen and the production of various free radicals, such as superoxide (O2●−), hydroxyl (●OH), and sulfate radicals (SO4●−). These behaviors were verified by ultraviolet–visible absorption spectroscopy, electron spin resonance spectroscopy, fluorescence spectroscopy, and radical quenching experiments. The production of radical species (particularly ●OH), which was negligible under dark conditions, is responsible for the enhanced degradation of propranolol in the presence of PMS under visible light. The positive effect of visible light on the propranolol degradation was observed in the PMS concentration range and the pH range of 100–3000 μM and 3–9, respectively. Compared to the visible light/platinum-loaded tungsten oxide (Pt-WO3) system, the visible light/PMS system showed a superior ability to degrade propranolol (degradation efficiency after 2 h of visible-light irradiation = 71.0% in the visible light/PMS system vs. 58.3% in the visible light/Pt-WO3 system).

Z-Scheme MoS2/TiO2/graphene nanohybrid photocatalysts for visible light-induced degradation for highly efficient water disinfection and antibacterial activity

A new Z-scheme MoS2/TiO2/graphene nanohybrid effectively degraded antibiotics, heavy metals and microorganisms under visible irradiation.

Visible Light-Induced Degradation of Propranolol with Peroxymonosulfate as an Oxidant and a Radical Precursor

Visible Light-Induced Degradation of Propranolol with Peroxymonosulfate as an Oxidant and a Radical Precursor

Rational design of uniformly embedded Cu/CoTe nanoparticles in freestanding rGO sheets for visible light-induced degradation of toxic dyes

Rational design of uniformly embedded Cu/CoTe nanoparticles in freestanding rGO sheets for visible light-induced degradation of toxic dyes

Sustainable 2D Bi2WO6/g-C3N5 heterostructure as visible light-triggered abatement of colorless endocrine disruptors in wastewater

Colorless endocrine disruptors (EDs) are generally known as interference chemicals with the hormonal system. Widespread usage of such pollutants in daily life leads to the hike in the level of EDs in water resources as well as drinking water resulting in various health issues upon ingestion unknowingly. Thus, it is a challenging issue to efficiently degrade colorless EDs under visible light in spite the report of several photocatalysts. Herein, we fabricated a composite comprising metal-free graphitic carbon nitride (g-C3N5) with Bi2WO6 that exhibits visible light-induced efficient degradation of colorless EDs. A simple hydrothermal polymerization method was adopted to prepare nanosheets of g-C3N5 loaded with Bi2WO6 nanoplates and the resulting heterostructure efficiently degrade tetracycline, 2-mercaptobenzothiazole, and chlorpyrifos under cheap visible light irradiation in a short period of time. The synergistic effect of g-C3N5 and Bi2WO6 components in the composite leads to efficient separation of photogenerated charge carriers via Z-scheme pathway and resulting in remarkable photocatalytic activity compared to individuals.

Fabrication of S-scheme ZnO/Zn3(PO4)2 heterojunction photocatalyst toward photodegradation of tetracycline antibiotic and photocatalytic mechanism insight

In this work, a S-scheme ZnO/Zn3(PO4)2 heterojunction photocatalyst was fabricated by a simple co-precipitation manner under reflux condition. The ZnO/Zn3(PO4)2 heterostructured nanocomposite was employed for the degradation of tetracycline antibiotic under UV and visible light irradiation. The structure, composition, morphology, and optical properties of the as-synthesized ZnO/Zn3(PO4)2 products were characterized by XRD, EDS, FESEM, TEM, UV–Vis DRS, and PL measurements. The hybrid ZnO/Zn3(PO4)2 nanoparticles exhibited the highest photocatalytic efficiency in the degradation of tetracycline under ultraviolet (97%) and visible (82%) light irradiation, which was ∼1.5 times more than sole Zn3(PO4)2 nanostructures. The promoted light harvesting and generated heterojunction interfaces between ZnO and Zn3(PO4)2 can obviously reduce the recombination rate of charge carriers in the ZnO/Zn3(PO4)2 heterostructure. Moreover, a reasonable photocatalytic mechanism of the UV and visible light-induced degradation of antibiotic over ZnO/Zn3(PO4)2 nanocomposites is suggested. The results indicated that under UV, the mechanism follows from the S-scheme in the presence of •O2− and •OH as predominant species, while upon visible, the type-II heterojunction utilizing •O2− as prevailing radical is possible.

Visible light-induced degradation of amoxicillin antibiotic by novel CuI/FePO4 p-n heterojunction photocatalyst and photodegradation mechanism

Antibiotic pollutant as a toxic wastewater is a critical global issue for human and ecosystems. In this work, we introduce a high-performance CuI/FePO4 heterojunction nanocomposite for the elimination of amoxicillin antibiotic under simulated sunlight radiation. The hybrid CuI/FePO4 nanoparticles exhibited an energy gap of 3.03 eV and photodegradation efficiency of 90%, which were better than those of CuI and FePO4 nanostructures. The prominent photocatalytic removal activity of the CuI/FePO4 heterostructures depends on the ultrafine particles, elevated visible-light absorption, and impressive separation and negligible recombination rate of electron-hole pairs due to the generation of p-n heterojunctions. We also presented a photocatalytic degradation pathway utilizing radical quenching analysis, which is based on fundamental function of the •OH and •O2− radicals in the photocatalytic elimination of amoxicillin by CuI/FePO4 nanocomposite. These functional properties of the CuI/FePO4 can be beneficial for the development of future photocatalyst materials.

Novel dual-effective Z-scheme heterojunction with g-C3N4, Ti3C2 MXene and black phosphorus for improving visible light-induced degradation of ciprofloxacin

Novel dual-effective Z-scheme heterojunction of graphitic carbon nitride/Ti3C2 MXene/black phosphorus (CN/MX/BP, CXB) was synthesized via a calcination process that achieved high photodegradation efficiency (> 99 %) of ciprofloxacin (CIP) under visible light irradiation (λ > 420 nm) within 60 min. The dual-effective CXB was reflected in the design of Z-scheme heterojunction and P-bridging effect, which were beneficial to form stable heterojunction and improve visible light-irradiated photocatalytic activity, including wider visible absorption range, faster carrier transfer and stronger redox ability. The P-bridging effect was designed from the reactions between the active P atom in the BP nanosheet and as-prepared CN (nitrogen deficiency). We rationally employed the binding energy shifts in X-ray photoelectron spectroscopy (XPS) and the redox ability of the photogenerated charges to prove the CXB was a Z-scheme heterojunction and the existence of P–N/P=N bonds. Moreover, the mechanisms of CIP degradation over the dual-effective Z-scheme heterojunction CXB were elucidated.

Synergistic effect of mesoporous graphitic carbon nitride and peroxydisulfate in visible light-induced degradation of atenolol: A combined experimental and theoretical study

The visible light sensitive metal-free mesoporous graphitic carbon nitride (mpg-CN) was fabricated for photodegradation of atenolol (ATN), a widely used drug for cardiovascular diseases. Peroxydisulfate (PDS) as an electron acceptor as well as a radical origin was introduced to enhance the catalytic performance, and retaining the nature of metal-free and mesoporous of mpg-CN. The photo-induced holes, SO4− and O2− were identified as the active species. Integrated with density functional theory (DFT) calculations and photoelectrochemical experiments, the interaction among PDS, catalyst, and ATN is unveiled. PDS can obtain an electron from the catalyst, hence to improve the separation of electron-hole pairs and activates itself. ATN has stable chemical adsorption states on catalyst surface. Then the electron-deficient catalysts can acquire electrons from ATN. In addition, primary degradation sites of ATN and following possible degradation pathways were explored with DFT calculations and mass spectrometry analysis.

Green Synthesis of Carbon Dots and Their Application as Photocatalyst in Dye Degradation Studies

This paper presents work on green synthesis of the carbon dots from leaves of Elettaria cardamomum (E.C) using simple ultra-sonication technique. In X-ray diffraction analysis, peak at 2θ value of 22.9° confirmed the amorphous nature of synthesized carbon dots. Furthermore, Raman investigations of the synthesized carbon dots illustrated D and G band at 1365 cm−1 and 1575 cm−1, respectively, showing graphitic structure of carbon dots. Similarly, Fourier transform infrared spectrum of carbon dots confirmed the presence of different functional groups such as C=O, C=C, OH, C–OH at absorption peaks values of 1715 cm−1, 1634 cm−1, 3257 cm−1 and 1027 cm−1, respectively. Photoluminescence spectral analysis of carbon dots confirms photoluminescent nature by exhibiting two emission peaks at 520 nm and 850 nm, respectively. UV–visible spectrophotometric investigations confirmed the presence of carbon dots showing two absorption peaks at 220 nm and 272 nm. After confirmation and characterization, the synthesized carbon dots were utilized for studying visible light-induced degradation of congo red and methylene blue dyes. This further investigation showed that the maximum degradation of congo red dye was observed in acidic media at pH 4 with a dye concentration of 5 ppm in a time interval of 50 min. For methylene blue dye, optimum degradation was observed in alkaline medium at a pH value of 8 with 5 ppm dye concentration in a time interval of 55 min.

Novel quantification of formation trend and reaction efficiency of hydroxyl radicals for investigating photocatalytic mechanism of Fe-doped TiO2 during UV and visible light-induced degradation of acid orange 7

A detailed mechanistic investigation of the hydroxyl radical (•OH) formation and organic pollutant degradation over transition metal-doped and undoped TiO2 photocatalysts was performed by the quantitative measurement of •OH and the identification of intermediate products under various experimental conditions. The Fe-doped TiO2 as a typical subject was prepared, characterized and used to degrade an azo dye Acid Orange 7 (AO7). It is indicated that the enhanced photocatalytic activity of Fe-doped TiO2 for AO7 degradation was attributed to the increase in surface area, the facilitated charge transfer via Fe-dopant, and a red shift of absorbable wavelength, maintaining a great formation of •OH under visible irradiation. The oxidation of H2O by holes was estimated as the major pathway of •OH formation rather than the reduction of dissolved O2 by electrons, and their formation trends reached to approximately 75% and 25%, respectively. Meanwhile the synergistic effect of Fe-dopant produced nearly 10% of extra •OH by visible light photoactivation. The intermediate products and pathways of AO7 degradation varied greatly with different photocatalysts and conditions of the process, involving several reaction mechanisms such as the azo bond cleaving, naphthalene oxidation, desulfonation, and hydroxylated products generation. Through the quantification of •OH-reacted efficiency we proposed, a stoichiometry of •OH affecting overall reaction mechanisms in the TiO2-assisted photodegradation of AO7 was further established. This study can provide new insights on how to better clarify the variation regularity of organic pollutant degradation from different treatments of the •OH-based advanced oxidation processes.