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Bandgap engineering of TiO2 nanoparticles through MeV Cu ions irradiation
摘要： The effect of 5 MeV Cu++ ions irradiation on structural and optical properties of Anatase TiO2 nanoparticles (TiO2-NPs) is investigated. For this purpose, TiO2-NPs are irradiated with different Cu++ ions ?uences, ranging from 1 (cid:1) 1015 to 1 (cid:1) 1016 ions/cm2 at room temperature. XRD results con?rm the Ti3O7 phase appear at the dose of 5 (cid:1) 1015 ions/cm2 and peak intensity of Ti3O7 phase gradually increases with an increase of Cu++ ions irradiation dose. At the dose of 1 (cid:1) 1016 ions/cm2 TiO2 Anatase phase were transformed to Rutile phase. Same observations are con?rmed from Raman spectroscopy. High resolution transmission electron microscopy (HRTEM) reveals that morphology converted into wavy shape and crystal structure detrioted with increase Cu ion irradiation dose to form vacancy loops and interstitial loops. Scanning electron microscopy (SEM) shows that TiO2-NPs have been fused to form a cluster of nanoparticles at high Cu ion beam dose, while bandgap of TiO2-NPs reduces from 3.19 eV to 2.96 eV as a function of Cu++ irradiation ?uence. These phase transformations and crystal damage are the responsible for optical bandgap reduction. The mechanism for the currently observed phase transformation of TiO2 and coalescence of TiO2-NPs are discussed in term of thermal spikes model.
关键词： Coalescence of NPs,Bandgap engineering,Cu++ irradiation,Rutile phase,TiO2 nanoparticles
更新于2025-09-10 09:29:36
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PHYTOSYNTHESIS OF SILVER NANOPARTICLES USING E. CAMALDULENSIS LEAF EXTRACT AND THEIR CHARACTERIZATION
摘要： Herein, we report a simple green synthesis of silver nanoparticles (Ag NPs) by the reduction of aqueous silver salt solution using leaf broth of Eucalyptus camaldulensis. The profile of synthesized silver nanoparticles was evaluated by using UV-visible spectrophotometer, X-ray diffractometer, atomic force microscope, energy-dispersive X-ray spectroscope and scanning electron microscope. Surface plasmon resonance peak of silver nanoparticles appeared at 425 nm in UV-vis spectra of silver nanoparticles. XRD studies clearly confirmed the crystalline nature of the synthesized nanoparticles. The EDX analysis disclosed the arranged inorganic composition of the synthesized Ag NPs. Atomic force microscopy investigation revealed 3D surface profile of nanoparticles. From the SEM images, the silver nanoparticles were found to be more or less spherical with an average diameter range of 110-250 nanometers.
关键词： E. camaldulensis,SEM,AFM,UV-visible spectrophotometry,XRD,Ag NPs
更新于2025-09-10 09:29:36
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Catechol oxidase mimetic activity of cadmium sulfide nanoparticles for the oxidation of L- 3,4 -dihydroxyphenylalanine
摘要： In the present work we have investigated the oxidation of L-3,4 -dihydroxyphenylalanine (L-Dopa) using colloidal cadmium sulfide nanoparticles (CdS NPs) as a photocatalyst. The CdS NPs were synthesized and characterized using UV-visible absorption spectroscopy, transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). It was demonstrated that the as-prepared CdS NPs mimiced the activity of the catechol oxidase enzyme. To the best of our knowledge, this is the first report on the oxidation of L-Dopa using semiconductor NPs. The kinetic analysis was carried out using the Michaelis-Menten equation. The results observed that the CdS NPs oxidized L-Dopa within 30 min of irradiation using a 200 W Hg(Xe) arc lamp. The oxidation product was identified using high performance liquid chromatography (HPLC). The HPLC analyses were carried out on a reverse-phase C18 column under isocratic conditions using methanol/water (10/90) as the mobile phase. The retention time of the product matched with that of dopachrome. The mechanistic studies indicated the participation of hydroxyl radicals (?OH) in the photocatalytic oxidation of L-Dopa.
关键词： CdS NPs,semiconductor,irradiation,photocatalytic,catechol oxidase
更新于2025-09-09 09:28:46
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pHydroxyl decorated g-C3N4 nanoparticles with narrowed bandgap for high efficient photocatalyst design
摘要： Zero-dimensional graphitic carbon nitride nanoparticles (0D g-C3N4 NPs) possess the advantages of non-toxicity, metal-free, and rich surface catalytic active sites. However, the complex preparation process, wide bandgap structure, easily particle aggregation and rapid carriers’ recombination still limit their development in photocatalysis. Herein, these issues are addressed by synthesizing a novel hydroxyl (-OH) modified g-C3N4 NPs with a simple hydrothermal method without using any etching agents. Besides the high hydrophily and small particle size, the -OH decorated 0D g-C3N4 NPs possess obvious narrowed bandgap and high reduction potential. To further improve their dispersity and carriers’ separation rate, 0D/3D g-C3N4 NPs/ZnS type II heterojunction is fabricated, which simultaneously improves the hydrophily, passivates the surface defects and extends the sunlight absorption range of ZnS. As a result, a high and cyclable photocatalytic activity of 112 μmol h-1 (5.6 mmol h-1 g-1) is achieved under visible light irradiation without any co-catalysts, which is 140 times higher than that of pure ZnS and much better than the pure 0D g-C3N4 NPs. A systematic study of photocatalytic mechanism is proposed by combining the theoretical calculations and experimental results. This work offers a new sight for the design of 0D g-C3N4 NPs based photocatalysts for H2 production.
关键词： g-C3N4 NPs,Narrowed bandgap,Hydroxyl,Hydrogen,Photocatalysis
更新于2025-09-09 09:28:46
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Total Aqueous Synthesis of Au@Cu <sub/>2?</sub><i> <sub/>x</sub></i> S Core–Shell Nanoparticles for In Vitro and In Vivo SERS/PA Imaging‐Guided Photothermal Cancer Therapy
摘要： Both accurate tumor navigation and nanostructures with high photothermal (PT) conversion efficiency are important but remain challenging to achieve in current biomedical applications. This study reports an anion exchange-based facile and green approach for synthesizing Au@Cu2?xS core–shell nanoparticles (NPs) in an aqueous system. In addition to the PT effect of the suggested NPs, the surface-enhanced Raman scattering (SERS) is also significantly improved due to the tailored localized surface plasmon resonance coupling between the Au metal core and the Cu2?xS semiconductor shell. Using an epitaxial strategy, Au@Cu2O NPs are first obtained by the in situ reduction of cupric hydroxide on a cresyl violet acetate-coated Au core; then, Au@Cu2?xS NPs are obtained via anion exchange between the S2? and Cu2O shell. Both the Cu/S atomic ratio and the Cu2?xS shell thickness can be adjusted conveniently. Hence, the ideal integration of the plasmonic Au core and Cu2?xS shell into a single unit is conducive not only to highly efficient PT conversion but also to the construction of a SERS-based navigator. This new type of SERS-guided NP, with enhanced photoacoustic signals, is an important candidate for both accurate tumor navigation and nondestructive PT treatment guided in vivo by two modes of optical imaging.
关键词： navigation treatment,photothermal therapy (PTT),Au@Cu2?xS core–shell nanoparticles (NPs),plasmonic enhancement,surface-enhanced Raman scattering (SERS)
更新于2025-09-09 09:28:46
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Ag/TiO <sub/>2</sub> NPs/TiO <sub/>2</sub> TF/Si Based Non-Volatile Memristor Device for Neuromorphic Computing Applications
摘要： Memristor device is a very promising emerging component for a revolution of the memory and computing applications in the recent years. It could be enhancing the field of artificial intelligence and helping the patients, suffering from various kinds of autism disorders, as well as in neuromorphic computing, neural networks, etc. This research article proposes fabricated non-volatile memristor device for neuromorphic computing applications. The demonstrate memory is based on Ag/TiO2 NPs/TiO2 TF/Si layers’ structure and achieves better conductivity and storage capacity, which could improve the performance of the neuromorphic computing as compared to conventional ones. The fabrication method of the proposed multi-layer memristor is examine with well precise techniques, which overcome the previous challenges. The surface morphology of the device is analysed by field emission gun scanning electron microscopy (FEGSEM) and Energy dispersive X-ray system. The rise time (Tr) of 2.5 s and fall time (Tf) of 3 s are demonstrated under ON/OFF white light illumination. While X-ray diffraction depicted that titanium dioxide nano particle, (TiO2 NPs) are crystalline in nature. Moreover, Photoluminescence and Raman analysis justify crystalline nature also and increasing oxygen vacancies concentration with the heating effect of TiO2 NPs. The electrical analysis reveals the driving mechanism under different sweeping voltages during SET and RESET resulting in low resistance state (‘ON’). Finally, capacitance-voltage characteristic of the proposed memory device shows excellent charge storage capacity within the dynamic range of operation.
关键词： Titanium Dioxide Nano Particles (TiO2 NPs),Memristor Devices,Neuromorphic Computing,Titanium Dioxide Thin Film (TiO2 TF)
更新于2025-09-09 09:28:46
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Graphitic Carbon Nitride Impregnated Niobium Oxide (g-C <sub/>3</sub> N <sub/>4</sub> /Nb <sub/>2</sub> O <sub/>5</sub> ) Type (II) Heterojunctions and Its Synergetic Solar-Driven Hydrogen Generation
摘要： Graphitic carbon nitride (g-C3N4) based catalysts are evolving in energy harvesting applications due to their robustness, nontoxicity, and most important photocatalytic efficiencies. In this work, we successfully engineered g-C3N4/Nb2O5 type (II) heterojunction via pulse sonochemical technique based on opposite charge-induced hetero-aggregation on the surface. The agglomerated spherical Nb2O5 nanoparticles (NPs) having diameter 30-40 nm observed on the lamellar surface of g-C3N4 in FESEM images. The XRD and XPS analysis confirm the orthorhombic phase and formation of the g-C3N4/Nb2O5 heterostructure. The FTIR spectra of g-C3N4/Nb2O5 show characteristic poly s-triazine bands from 1250 to 1650 cm-1. Moreover, g-C3N4/Nb2O5 exhibited the lower bandgap value of 2.82 eV as compared to Nb2O5 (3.25eV) with significant redshift and enhance visible light absorption. The Mott-Schottky (MS) analysis confirms the formation of heterojunction between g-C3N4 and Nb2O5, with significant band shifting towards lower hydrogen evolution reaction (HER) potential. The g-C3N4/Nb2O5 heterojunctions showed many folds enhanced photocurrent response from photoelectrochemical (PEC) water splitting, and the value reached to – 0.17 mA/cm2 with good stability and insignificant dark photocurrent at 1.0 V vs RHE. The electrochemical impedance spectroscopic (EIS) measurements further elucidate the suppression of photogenerated electrons/holes as the radius of the semicircle significantly decreased in case of heterojunction formation. The enhanced photocatalytic hydrogen generation by the heterostructures could be attributed to the effective formation of heterojunctions between the g-C3N4 and Nb2O5 semiconductors, causing the migration of the photogenerated electrons and holes, hence increasing their lifetimes.
关键词： Pulse Sonication,PEC Water Splitting,g-C3N4,Photocurrent density,Nb2O5 NPs
更新于2025-09-09 09:28:46
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Green engineered nano MgO and ZnO doped with Sm3+: Synthesis and a comparison study on their characterization, PC activity and electrochemical properties
摘要： Structural, photocatalytic, photoluminescence and electrochemical activities of rare earth (RE) metal ions (Samarium (Sm3+)) doped Magnesium oxide (MgO) and Zinc oxide (ZnO) nanoparticles (NPs) prepared by using Cicer artinum powder as a fuel via green solution combustion method were discussed in detail. The synthesized NPs were found to have an average crystal size of around 25 nm as established by powder X-ray diffraction (PXRD). The semiconductor behavior has been confirmed by the study of energy band gap via diffuse reflectance spectroscopy (DRS). The conductivity of the samples was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was observed that on 378 and 398 nm excitation of both the samples, it emits yellow and white radiation resonating with the ideal white light. The Rare Earth (RE) doped NPs have been applied as a novel photocatalyst for removal of rodhamin-B (rh-B) and malachite green (MG) dyes. The release of OH radicals played a crucial role in dye degradation; its extent depending on the chemical structure and photocatalyst dosage. The photocatalytic activity (PCA) was found to be maximum for MgO:Sm3+ (0.1mol %) under UV light and ZnO:Sm3+ (1 mol %) under sunlight.
关键词： Cicer arietinum,MgO NPs,malachite green (MG),ZnO NPs,rhodamin-B (rh-B)
更新于2025-09-04 15:30:14
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Structural and optoelectronic properties of Ce-Al2O3 nanoparticles prepared by sol-gel precursors
摘要： Pure and Ce-doped Al2O3 nanoparticles (NPs) were synthesized in different cerium percentages of 1%, 2%, and 3% by cerium chloride and aluminum nitrate precursors in the presence of powerful reducing agent-NaBH4 and CTAB stabilizers using sol-gel method. To examine the crystal, morphological, optical, and electronic properties, the XRD, FESEM, TEM, FTIR, UV-DRS, and PL analyses were used for the heated samples in 1000 °C for 4 hours. The XRD analysis indicated that the pure sample has γ, δ and θ phases, and the structure remained unchanged when Ce impurity was increased. The EDS analysis showed that the percentage of Al element was 47.40 wt% in the pure sample and that it increased to 53.83 wt% for 1% doped sample increasing Al ions in tetrahedral and octahedral sites of alumina through increasing Ce impurities. The TEM results revealed the sphere-like particles with mean particle size of 26 nm in diameter at a 3% level of impurity. The FTIR result showed that an increase in AlO4 adsorption peak in 821 cm-1 compared to AlO6 adsorption peak in 619 cm-1 was due to the dominance of vibrating bonds of tetrahedral sites rather than octahedral sites in alumina. The optical UV-DRS analysis also demonstrated the redshift configuration in a sample by increasing Ce dopant and reducing energy bandgap from 4.10 to 3.26 eV for pure and 3% Ce-doped Al2O3 NPs, respectively. Finally, the photoluminescence (PL) results indicated that increasing Ce dopant reduced electron-hole recombination leading to an increase in photocatalytic activity.
关键词： Chemical Synthesis,Cerium dopant,Sol-gel,Ceramics,Al2O3 NPs
更新于2025-09-04 15:30:14
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Magnetically Recyclable MoS <sub/>2</sub> /Fe <sub/>3</sub> O <sub/>4</sub> Hybrid Composite as Visible Light Responsive Photocatalyst with Enhanced Photocatalytic Performance
摘要： Photocatalysis is one of the most promising technologies in wastewater treatment. However, the inactivity to visible light and the inconvenience to recycle severely limit its practical application. In this work, via a facile hydrothermal method, Fe3O4 NPs were integrated onto the surfaces of 3D ball-flower-like MoS2 microspheres as efficiently visible light responsive and magnetically recyclable photocatalysts. Experimental results indicate that, an optimal loading amount (20 wt.%) of Fe3O4 NPs can not only effectively enhance the photocatalytic ability of the MoS2/Fe3O4 (MF) hybrid composite with approximately 2 times better than pure MoS2, but also make it conveniently recycle from water by an external magnetic field. The photoelectrochemical studies also reveal that the incorporation of Fe3O4 NPs can effectively enhance the charge transfer rate and accelerate separation of photo-induced charge carriers. The surface catalytic mechanism of MF hybrid composite was also explored through XPS spectra. With both the excellent photocatalytic performance and magnetical recyclability, the 20wt%-MF hybrid composite is considered to be a promising and competitive photocatalyst for wastewater treatment utilizing solar energy.
关键词： magnetical recyclability,Fe3O4 NPs,MoS2,photocatalyst,visible light responsive
更新于2025-09-04 15:30:14