Activity For Degradation Of Dye Research Articles

Photocatalytic dye degradation and antibacterial activities of CeO2/g-C3N4 nanomaterials for environmental applications.

The uncontrolled dumping of synthetic dyes into water sources has posed severe hazards to the ecosystem. For decades, several materials with low cost and high efficiency have been investigated for dye degradation. Photocatalytic degradation is regarded as a successful strategy since it utilizes sunlight to transform harmful pollutants into nontoxic compounds without using oxidative agents. The photocatalytic potentials of CeO2/g-C3N4 (CG) were investigated in this work using a simplistic ultrasonication process. Here, the amount of CeO2 was fixed, and g-C3N4 was varied in the ratio (1:x, where x = 1, 2, and 3) and abbreviated as CG1, CG2, and CG3. Characterization techniques such as Fourier transforms-infrared spectroscopy, thermal gravimetric analysis (TGA), powdered X-ray diffraction, ultraviolet-visible spectroscopy, etc. were used to characterize structural analysis, optical properties, particle size, and chemical bonds of the prepared nanocomposites. The photocatalytic results showed that CG2 effectively degraded rose bengal (RB) and crystal violet (CV) dyes when exposed to visible light irradiation as compared to pure GCN and CeO2. The antibacterial activity analysis further supported the potential application of prepared photocatalyst as a disinfectant agent against both gram-positive (Staphylococcus aureus and Bacillus cereus) and gram-negative (Salmonella abony and Escherichia coli) pathogenic strains of bacteria.

Biosynthesis, characterization, and evaluation of antibacterial and photocatalytic dye degradation activities of silver nanoparticles biosynthesized by Chlorella sorokiniana

Biosynthesis, characterization, and evaluation of antibacterial and photocatalytic dye degradation activities of silver nanoparticles biosynthesized by Chlorella sorokiniana

Enhanced photocatalytic activity for degradation of ofloxacin and dye by hierarchical flower-like ZnS/MoS2/Bi2WO6 heterojunction: Synergetic effect of 2D/2D coupling interface and solid sulfide solutions

To strengthen the photocatalytic degradation of antibiotics and organic dyes, the band structure engineering serves as an efficient approach, which can be realized by constructing heterostucture photocatalysts. Herein, 0D/2D/2D ZnS/MoS2/Bi2WO6 (ZMB) hierarchical flower-like microspheres were smoothly prepared via in-situ growth of Bi2WO6 nanoparticles on ZnS/MoS2 surfaces. The results illustrated that the content of Bi2WO6 played a crucial role in regulating the photocatalytic activity of ZMB heterostructures. ZMB-7 showed a better degradation capacity compared to ZnS/MoS2 and other ZMB composites, and the degradation rates of ofloxacin (OFL) and rhodamine B (RhB) respectively reached 98.5% and 91.1% under light illumination. The enhanced photocatalytic activity could be attributed to the large specific surface, improved separation of photogenerated carriers, as well as rapid charge transfer by combining the advantage of 2D coupling interfaces generated from MoS2/Bi2WO6 and composition-controlled band gap in solid sulfide solutions. On the basis of active species trapping experiments and HPLC-MS tests, a possible photocatalytic mechanism and gradation pathway for OFL were further proposed. The ternary ZnS/MoS2/Bi2WO6 heterojunction with enhanced photocatalytic activities in the work may have vital applications for environmental purification owing to its synergistic effects between composition and microstructure.

Fabrication of Fe3O4@Ti-PDA nanoparticles with enhanced photocatalytic activities for degradation of organic dye

In this paper, we synthesized a core-shell structured Fe3O4@Ti-PDA nanoparticles as photocatalyst by a facile method in environmental friend mild reaction conditions without organic solvent. Firstly, Fe3O4 was synthesized by solvothermal method, and Fe3O4@PDA was formed by dopamine (DA) self-polymerization to encapsulate Fe3O4 to form polydopamine (PDA) lager. Then, the surface of Fe3O4@PDA was wrapped by coordinating bis(2-hydroxypropionic acid) diammonium dihydroxide(Ti-BALDH) with DA combined DA self-polymerizing to obtain Fe3O4@Ti-PDA. As control, we synthesized another photocatalyst Fe3O4@PDA@TiO2. Compared with Fe3O4@PDA@TiO2 (band gap 3.0 eV), Fe3O4@Ti-PDA had a narrower band gap (2.5 eV) and a wider light absorption range (from ultraviolet to visible light to near-infrared light), as a photocatalyst, which can make full use of sunlight to improve photocatalytic efficiency. Meanwhile, magnetic core of Fe3O4@Ti-PDA made it was easy to separate from aqueous solution for convenient recovery. Using methylene blue (MB) as model pollutant, the degradation efficiency of Fe3O4@Ti-PDA on MB reached to 92.4% under visible light irradiation for 120 min without cocatalyst, while for Fe3O4@PDA@TiO2 only to 32.5%. The result indicated Fe3O4@Ti-PDA enabled photocatalytic oxidation and rapid separation when photogenerated electron-hole pairs were generated. After three recycles, the degradation efficiency of Fe3O4@Ti-PDA on MB still remained at 86.47%, showing good recycle stability.

The Biogenic Synthesis of Cobalt Monometallic and Cobalt–Zinc Bimetallic Nanoparticles Using Cymbopogan citratus L. Leaf Extract and Assessment of Their Activities as Efficient Dye Removal and Antioxidant Agents

In this work, green synthesized cobalt monometallic and cobalt–zinc bimetallic NPs were prepared by bioreduction of metallic salts with Cymbopogan citratus plant extract. Biosynthesized cobalt nanoparticles (NPs) and cobalt–zinc bimetallic NPs were characterized using diverse techniques such as FTIR, UV-Visible spectroscopy, SEM, XRD, and EDX analyses. UV-visible spectra for green-synthesized cobalt monometallic and cobalt–zinc bimetallic NPs were in the range between 300 to 350 nm, which confirmed the formation of stable monometallic and bimetallic NPs. The average particle size of CoNPs calculated by XRD analysis was found to be 22.77 nm and that of Co-Zn BMNPs was 14.8 nm. Different functional groups in the Cymbopogan citratus plant extract, which served as a reducing and stabilizing agent for NPs, were identified by FTIR spectra. Cobalt NPs and cobalt–zinc bimetallic NPs were used in the evaluation of antioxidant, anti-inflammatory, and dye degradation activity. Green-synthesized cobalt monometallic NPs and cobalt–zinc bimetallic NPs exhibited excellent antioxidant activity with the scavenging of DPPH free radicals. Green synthesized cobalt NPs and cobalt–zinc bimetallic NPs were utilized for the removal of methylene blue (MB) dye. Different parameters such as the effect of temperature, pH, and dye concentration on adsorbent doses were analyzed and optimized. The best dye removal percentage was obtained with Co-Zn BMNPs compared with CoNPs. Cobalt NPs and cobalt–zinc bimetallic NPs did not display good anti-inflammatory activity because of the presence of secondary metabolites which inhibited them to react with proteins.

Sida cordata assisted bio-inspired silver nanoparticles and its antimicrobial, free-radical scavenging, tyrosinase inhibition, and photocatalytic activity (4 in 1 system)

This study presents the successful application of Sida cordata (SC) extract in the renewable bio-inspired green synthesis of silver nanoparticles (AgNPs). The aqueous-alcoholic extract of S. cordata (aerial part) was effectively used for the silver nanoparticles (AgNPs) green synthesis. Physiochemical techniques, such as UV-Vis, FT-IR, XRD, FE-SEM, and HR-TEM analyses were applied to characterize the green synthesized AgNPs. UV-vis spectra showed characteristic plasmon resonance spectra with the maximum at 447 nm; the crystalline nature of SC-AgNPs was confirmed by XRD. Shape, size, and morphology were examined by FE-SEM and HR-TEM and the results confirmed the spherical shape of particles with an average diameter of about 48 nm. The presence of alcohols or phenols, carboxylic acids, ketones, amine functional groups were revealed by FTIR. In vitro biological activity studies portrayed that the synthesized SC-AgNPs have potential antimicrobial activity against Gram(−)ve and Gram(+)ve bacteria in a dose-dependent manner, dose-dependent antioxidant activity against DPPH (75.47 ± 2.5%) and a dose-dependent inhibition of tyrosinase (98.25 ± 1.25% at a dose of 110 µg/ml), moreover, the nanoparticles show excellent photocatalytic activity for methylene blue dye degradation. The AgNPs synthesized here were considered a 4 in-1 system.

Electric Poling Effect on Piezocatalytic BaTiO3/Polymer Composites for Coatings

BaTiO3-polymer paint composites were fabricated to examine piezocatalysis activities. Dye degradation and antibacterial activities were recorded under ultrasonication. The effect of polarization was also examined for the catalysis process. There were significant enhancements in catalysis performance in the poled sample; 80–90% dye degradation was recorded (240 min) in poled samples of BaTiO3-polymer paint composites. The above observations indicate that these composites can be utilized as coatings for self-cleaning applications.

Green Synthesis of Iron Oxide Nanoparticles Using Psidium guajava L. Leaves Extract for Degradation of Organic Dyes and Anti-microbial Applications

Among various metal and metal oxide nanoparticles, iron-oxide nanoparticles (IONPs) have been more widely used for the degradation of harmful organic dyes and the inhibition of microbial growth; on the other hand, it positively affects mammalian cells. Green synthesis of IONPs has piqued the interest of researchers because it improves stability and is an environmentally friendly method of avoiding the use of harmful chemicals as a reducing agent. In this study, IONPs were synthesized using Psidium guajava leaf extract, which was further applied for its industrial dye degradation and anti-microbial activities. UV–visible spectroscopy, FTIR, XRD, XPS, EDX, FE-SEM, HR-TEM, and Zeta potential analysis were used to characterize the synthesized nanoparticles. The synthesized IONPs managed to degrade methylene blue (MB) and methyl orange (MO) in the presence of H2O2. The degradation efficiency was 82.1% in 95 min and 53.9% in 205 min for MB and MO, respectively. Likewise, the synthesized IONPs showed good anti-bacterial activity with a ZOI of 13 mm for both Shigella sonnei and Staphylococcus aureus gram-positive bacteria. Similarly, they demonstrated good anti-fungal activity with ZOI of 15 mm and 13 mm for Candida tropicalis and Candidaalbicans, respectively. Thus, the IONPs can combat harmful organic dyes, and they can terminate the pathogenicity of several human pathogens.

Eco-friendly and solar light-active Ti-Fe2O3 ellipsoidal capsules’ nanostructure for removal of herbicides and organic dyes

In this work, Ti-doped Fe2O3 with hollow ellipsoidal capsules nanostructure has been prepared in a green manner using plant extract (flax seed). This new green hematite nanomaterial has been evaluated as photocatalyst for water treatment by testing its activity for degradation of bromophenol blue dye (BPB) and 2,4-dichlorophenoxy acetic acid (2,4-D) herbicide. For a better understanding of the green material properties, a comparison with the pristine Fe2O3 nanospheres previously prepared by the same procedure is included. Structural and optical properties of the green prepared materials are studied. The results revealed the success doping of Ti4+ at Fe3+ site, without forming any of TiO2 phases. It was also found that the Ti doping resulted in the reduction of the band gap of Fe2O3 as well as changing the morphology. The Ti-doped Fe2O3 nanomaterial exhibited an enhanced photocatalytic activity either for BPB dye or for 2,4-D degradation with more than 2 times higher rate than that using pristine Fe2O3.

Biosynthesis of zirconium nanoparticles (ZrO2 NPs) by Phyllanthus niruri extract: Characterization and its photocatalytic dye degradation activity.

The present study focused on microwave assisted synthesis of zirconium nanoparticles (ZrO2NPs) using leaf extract of Phyllanthus niruri as ecofriendly approach and assessed its antimicrobial and bioremediation efficiency. Visual color transition from yellow to brown indicates the formation of ZrO2NPs which was further substantiated by UV-Visible absorption peak at 300nm. Dynamic Light Scattering (DLS) analysis revealed that the average particle size of ZrO2NPs as 121.5nm with negative zeta potential of -22.6 mv. Scanning electron microscopic analysis showed spherical shaped nanoparticles with an average size of 125.4nm. Results of photocatalytic studies revealed that ZrO2NPs exhibited 74%, 62% and 57%, dye degradation for methyl red, methyl orange, and methyl blue respectively. Antimicrobial studies depicted that ZrO2NPs exhibited bactericidal activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Aspergillus niger at dose of 200μg/mL. Overall results of the present study revealed biogenic synthesis of ZrO2 NPs with potent bioremediation and antimicrobial properties.

Architectural MCM 41 was anchored to the Schiff base Co(II) complex to enhance methylene blue dye degradation and mimic activity

A sequence of Schiff base Cobalt (II) Mobile Composite Matter 41 heterojunction (SBCo(II)-MCM 41) was prepared by post-synthetic protocols. Various characterization techniques were used to characterize the above samples and MCM 41: Morphology, functional groups, optical properties, crystalline nature, pore diameter, and binding energy by scanning electron microscope (SEM), High-resolution transition electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FTIR), Ultra Violet-Visible Spectroscopy (UV), X-ray powder diffraction (XRD), Brunauer-Emmett-Teller (BET) and X-ray Photoelectron Spectroscopy (XPS). After the encapsulation of SBCo(II) on the MCM 41, the intensity in the 100-plane in powder x-ray diffraction (XRD) decreased significantly; moreover, the light absorption behavior in UV analysis was improved. The change in the surface area and the decrease in the pore diameter of the sample were also demonstrated by the BET study. The XPS results confirmed the presence of Si, O, C, N, and Co in the SBCo(II)-MCM 41 complex. The photocatalytic performance of MCM 41 and SBCo(II)-MCM 41 materials tested by the degradation of methylene blue dye (MBD) shows that MCM 41 immobilization with SBCo(II)complex is rapidly degraded under natural sunlight irradiation. The optimized 10 mg SBCo(II)-MCM 41 catalyst concentrations showed effective enhancement with the highest efficiency of 98% achieved within 2 h compared to the other two SBCo(II)-MCM 41 concentrations. Moreover, the catalytic efficiency of SBCo(II)-MCM 41 showed a biomimetic reaction without using an oxidant, which exposed it as an effective catalyst for amine to imine conversion; it was useful in the medical field for enzymes with structural assembly.

Antioxidant, Anti-Bacterial, and Congo Red Dye Degradation Activity of AgxO-Decorated Mustard Oil-Derived rGO Nanocomposites.

Scaling up the production of functional reduced graphene oxide (rGO) and its composites requires the use of low-cost, simple, and sustainable synthesis methods, and renewable feedstocks. In this study, silver oxide-decorated rGO (AgxO−rGO) composites were prepared by open-air combustion of mustard oil, essential oil-containing cooking oil commercially produced from the seeds of Brassica juncea. Silver oxide (AgxO) nanoparticles (NPs) were synthesized using Coleus aromaticus leaf extract as a reducing agent. Formation of mustard seed rGO and AgxO NPs was confirmed by UV-visible characteristic peaks at 258 nm and 444 nm, respectively. rGO had a flake-like morphology and a crystalline structure, with Raman spectra showing clear D and G bands with an ID/IG ratio of 0.992, confirming the fewer defects in the as-prepared mustard oil-derived rGO (M−rGO). The rGO-AgxO composite showed a degradation efficiency of 81.9% with a rate constant k−1 of 0.9506 min−1 for the sodium salt of benzidinediazo-bis-1-naphthylamine-4-sulfonic acid (known as the azo dye Congo Red) in an aqueous solution under visible light irradiation. The composite also showed some antimicrobial activity against Klebsilla pneomoniae, Escherichia coli, and Staphylococcus aureus bacterial cells, with inhibition zones of ~15, 18, and 14 mm, respectively, for a concentration of 300 µg/mL. At 600 µg/mL concentration, the composite also showed moderate scavenging activity for 2,2-diphenyl-1-picrylhydrazyl of ~30.6%, with significantly lower activities measured for AgxO (at ~18.1%) and rGO (~8%) when compared to control.

Fast synthesis of NaNbO3 nanoparticles with high photocatalytic activity for degradation of organic dyes

AbstractNaNbO3 nanoparticles were obtained using the microwave‐assisted hydrothermal method followed by heat treatment. It has been shown that heat treatment to increase the crystallinity of the material and modifies particle shape, from nanowires to nanograins. Nanowires with a diameter of approximately 35 nm and a length of tens of micrometers were obtained in the shortest time ever reported in the literature. Particles in the shape of nanograins with a diameter of approximately 35 nm were obtained by burning the nanowires. The photocatalytic activity of the nanoparticles was investigated through the photodegradation of Rhodamine B dye. Electronic structure analysis using density functional theory (DFT) along with experimental techniques was performed to help understand the photocatalytic activity of each sample. The obtained nanoparticles were highly favorable for photocatalytic applications, especially the nanograins, which degraded 100% of the dye in 50 min.

Biosynthesis of silver and gold nanoparticles using Sargassum horneri extract as catalyst for industrial dye degradation

This study focuses on the green synthesis of silver and gold nanoparticles using the marine algae extract, Sargassum horneri , as well as the degradation of organic dyes using biosynthesized nanoparticles as catalysts. The phytochemicals of the brown algae Sargassum horneri acted as reducing and capping agents for nanoparticle synthesis. Ultraviolet–visible absorption spectroscopy, dynamic light scattering, high-resolution transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectroscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy were used to characterize the biosynthesized nanoparticles. The green-synthesized SH-AgNPs and SH-AuNPs exhibited high catalytic activity for degradation of organic dyes, such as methylene blue, rhodamine B, and methyl orange. The reduction reactions of dyes are based on pseudo-first-order kinetics.

Surfactant‐Enhanced Nano Spinel Oxide for Applications in Catalysis, Dye Degradation and Antibacterial Activity

AbstractNovel surfactant supported Mn−Co−Ni oxide was effectively synthesized by simple and economic co‐precipitation method to investigate the efficiency of catalytic reduction of 4‐nitrophenol, degradation of methylene blue and antibacterial properties. The optical, structural and chemical compositions were cautiously analyzed by X‐ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), X‐ray photoelectron microscopy (XPS), ultraviolet‐visible (UV‐Vis), Fourier transform infrared (FT‐IR), Brunauer‐Emmett‐Teller (BET) and dynamic light scattering (DLS) analyses. XRD analysis showed cubic structure with average crystallite size of 19–21 nm. FESEM images confirmed the combination of spherical, needle, plate and rod like shapes. Accordingly, a high specific surface area of 55.66 m2 g−1 was achieved by urea/Mn−Co−Ni oxide. Band gap of ternary metal oxide was found in the range of 3.4‐3.6 eV. The XPS analysis confirmed the presence of manganese, cobalt and nickel as major parts with a 2p core level region. The M−O bond formation was confirmed by the peak appeared in the range of 500–600 cm−1. The negative charge of ternary metal oxide was confirmed by negative zeta potential value. The reduction of 4‐nitrophenol was carried out by Mn−Co−Ni oxide with the efficiency of >99 % and the degradation efficiency against methylene blue was studied. The synthesized catalyst was potent against S. aureus at higher concentration.

Leucas aspera mediated SeO nanoparticles synthesis for exploiting its pharmaceutical efficacy

The aim of this study is to synthesis Selenium oxide (SeO) nanoparticles using the leaf extract of Leucas aspera . The leaf extract has been reported to show phytochemicals effective for reducing Selenium precursors. Furthermore, these phytochemicals has being reported to show capping and stabilizing property. As-prepared nanoparticles physico-chemical properties were assessed by a array of various characterization technique. UV-Vis and XRD assessment showed maximum absorbance at 273 nm with high crystalline property. Qualitative assessment using FTIR assessment was performed to assess the phytochemical based functional groups presence which helped in reducing, stabilizing of the prepared nanoparticles. Morphological assessment of nanoparticles showed spherical attributes with good aggregation. Functional attributes of SeO nanoparticles for exploiting its pharmaceutical application, illustrated a significant antibacterial activity against both gram negative and gram-positive strains comparable to commercially available antibiotics. Moreover, MTT assay was employed to assess anticancer behaviour of SeO nanoparticles towards MG-63 cells, which showed effective reduction in cell viability. Furthermore, the study confirms photo catalytic degradation property of SeO nanoparticles towards dye degradation. The study not only discusses the SeO nanoparticles physico-chemical and functional properties, but and also opens future scope of SeO in clinical and environmental applications. • Prepared SeO nanoparticles from Leucas aspera stem extract by green synthesis. • Enhanced structural, dye degradation and antibacterial activity. • MTT assay method is used for the analysis of the anticancer activity of SeO.

Regulating of MnO2 photocatalytic activity in degradation of organic dyes by polymorphic engineering

Different phase nanostructured MnO2, including α-, β-, γ-, and δ-MnO2, were prepared by a hydrothermal route. Their photocatalytic activities in the degradation of cationic (methylene blue) and anionic (methyl orange) dyes were compared for the first time. The as-prepared oxides were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and low-temperature nitrogen adsorption-desorption techniques. It was shown that the highest efficiency was achieved in the degradation of cationic methylene in the presence of the δ-MnO2 photocatalyst (conversion of methylene blue was 90.4% after 180 min). These results are explained by unique physicochemical properties of the δ-MnO2 polymorph. It was observed that there is a synergetic effect between various physicochemical properties of δ-MnO2 which allows to obtain the high photodegradation efficiency: high adsorption ability towards methylene blue, unique 2D morphology, lower Mn–O bond strength, and high surface Mn4+/Mn3+ molar ratio. The reaction mechanism as well as the main products of the methylene blue photooxidation process over δ-MnO2 were also investigated.

A novel alginate/PVA hydrogel -supported Fe3O4 particles for efficient heterogeneous Fenton degradation of organic dyes

A major deficiency of the traditional Fenton technology in practical application is the production of a large amount of sludge. In this paper, we first synthesized a kind of magnetic alginate/PVA hydrogel microspheres by inverse emulsion method along with coprecipitation method. Through the cross-linking action of iron ions, sodium alginate and polyvinyl alcohol formed a stable interpenetrating network structure, in which the magnetic Fe3O4 nanoparticles were stably wrapped. After drying, a novel alginate/PVA hydrogel-supported magnetic Fe3O4 particles were obtained. FTIR,XRD，SEM and EDS were used to confirm the composition and structure of the composite material. Furthermore, the resultant alginate/PVA hydrogel-supported Fe3O4 particles perform excellent broad-spectrum catalytic activity for Fenton degradation of organic dyes. Especially, compared with the classical Fenton catalyst, the double-crosslinked structure in the alginate/PVA hydrogel endows the magnetic Fe3O4 particles with high stability and recyclability. After reuse for six times, the mass loss of the composite material is only 10 %, which can avoid the generation of iron sludge in Fenton-like reaction to the greatest extent.

Synthesis of a Polyoxometalate-Encapsulated Metal-Organic Framework via In Situ Ligand Transformation Showing Highly Catalytic Activity in Both Hydrogen Evolution and Dye Degradation.

In situ molecular transformation under hydrothermal conditions is a feasible method to introduce distinct organic ligands and suppress competitive reactions between different synthons. However, this strategy has not yet been explored for the preparation of polyoxometalate (POM)-encapsulated metal-organic frameworks (MOFs). In this work, we designed and prepared a new compound, [Co2(3,3'-bpy)(3,5'-bpp)(4,3'-bpy)](H2O)3[SiW12O40] (1) (4,3'-bpy = 4,3'-dipyridine, 3,5'-bpp = 3,5'-bis(pyrid-4-yl)pyridine, and 3,3'-bpy = 3,3'-bis(pyrid-4-yl) dipyridine), via an in situ ligand synthesis route. The compound shows a novel POM-encapsulated MOF structure with two pairs of left- and right-handed double helixes. These left- and right-handed helical chains further lead to triangular and rhombus-like channels, respectively. Moreover, the as-synthesized title compound shows superior electrocatalytic activity toward the hydrogen evolution reaction (HER) in 1 M KOH aqueous solution with a low overpotential and Tafel slope of 92 mV and 92.1 mV dec-1, respectively, under a current density of 10 cm-2. Also, the compound exhibits a high activity for the photocatalytic degradation of the dye rhodamine B. The excellent performance of the compound may be attributed to the synergistic effect between W and Co elements and the presence of encapsulated POMs. The title compound proves that it is possible to prepare multifunctional MOFs with POMs and transition metals showing HER activity and dye degradation activity.

Local dipole enhancement of space-charge piezophototronic catalysts of core-shell polytetrafluoroethylene@TiO2 nanospheres

This study demonstrates the hydrothermal treatment of core-shell polytetrafluoroethylene (PTFE) nanoparticles decorated with TiO2 (h-PTFE@TiO2); this material exhibits strain-induced local dipole enhancement of the space-charge piezopotential that improves the photocatalytic effect. Under acoustic cavitation, dielectric barrier discharge and electric dipole formation are initiated in voids within the PTFE nanoparticles and at the TiO2–PTFE interface. The h-PTFE@TiO2 nanoparticles (NPs) have exceptionally high catalytic activity in organic dye degradation because of the local dipole enhancement of photoinduced charge separation with a carrier lifetime of 3.14 ns. The observed rate constant of the h-PTFE@TiO2 NPs in the piezophototronic reaction reaches 0.1388 min−1, which is 17 times that of the photocatalytic reaction (0.0084 min−1) and 66 times that of the piezocatalytic reaction (0.0021 min−1). Computational simulation reveals that large strain-induced space charge piezoelectric polarization induces an internal electric field between the unsaturated PTFE (fluorine vacancies) and TiO2 surface. The piezopotential has a critical role in band bending at PTFE-TiO2 interfaces to enhance the electron-hole separation when PTFE is constrained in TiO2 shells. Results of piezoresponse force microscopy reveal that the piezoelectric coefficient d33 of PTFE is approximately 79.77 pCN−1. The findings provide insights into catalytic activity for environmental remediation.