Synthesis of edge-site selectively deposited Au nanocrystals on TiO2 nanosheets: An efficient heterogeneous catalyst with enhanced visible-light photoactivity

Enhanced Photocatalytic Degradation of Bisphenol A by a Novel MOF/CuFe2O4 Composite in Wastewater Treatment

The synergistic effects of a CuFe₂O₄ and cobalt/nickel metal organic framework (Co/Ni-MOF) based composite (MOF/CuFe₂O₄) were explored for photodegradation of Bisphenol A (BPA), various MOF/CuFe₂O₄ composites were synthesized via a hydrothermal method, By adjusting CuFe₂O₄ to Co/Ni-MOF mass ratios of 2:1, 1:1, and 1:2 and were denoted as MOF/CuFe₂O₄ (2:1), MOF/CuFe₂O₄ (1:1), and MOF/CuFe₂O₄ (1:2), respectively. The composite MOF/CuFe₂O₄ (1:1) with a band gap energy (Eg) of 2.28 eV exhibited excellent photocatalytic activity achieving 98% degradation of a 10 ppm BPA solution under visible light (50 W) irradiation within 75 min, at pH 3, 25°C. This process achieved a quantum yield (QY) of 9.10 × 10-6 molecules photon-1 and a space-time yield (SY) of 9.10 × 10-7, highlighting the composite's efficiency and potential for practical applications. Visible-light absorption efficiency improved as photon energy increased (25 to 50 W) and facilitated the generation of˙ O 2 - radicals. Kinetic studies indicated a first-order reaction rate (R 2 = 0.964) for BPA photodegradation by MOF/CuFe₂O₄ (1:1) composite. Additionally, the MOF/CuFe₂O₄ composite demonstrated superior antimicrobial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) under light compared with dark environment. Remarkably, the composite maintained its photocatalytic efficiency over at least six cycles. The results of the current study highlight the effectiveness and reusability of the MOF/CuFe₂O₄ (1:1) composite as a nanomaterial for the photodegradation of BPA and its potential applications in water treatment.

Dual-Function Nanocomposites: CuS@ZnO P-N Heterojunctions for Enhanced Light-Driven Photocatalysis and Microbial Inactivation

Organic dyes pose significant environmental and health concerns, including increased carcinogenicity and detrimental effects on photosynthesis due to elevated levels of BOD and COD. Herein, a hydrothermal approach was employed to synthesize CuS@ZnO nanocomposites. Structural properties of the prepared nanocomposites were confirmed and evaluated by using XRD and FTIR techniques. Morphological characteristics and particle size (showing an average size of around 40 nm) were evaluated by FESEM. To assess their effectiveness, the prepared nanomaterials were investigated against the photodegradation of rhodamine B (RhB). The CuS@ZnO-b composite, with a 1:1 M ratio, achieved an impressive 94.31% photodegradation efficiency against 10 ppm RhB with a quantum yield of 1.97 × 10-5 molecules photon-1 (within 120 min at pH 4.0, 50-W light intensity and 40°C). The ability of the CuS@ZnO photocatalyst to absorb visible light effectively and generate free radicals was significantly enhanced by increased photon energy activation. The antimicrobial effectiveness of the CuS@ZnO nanocomposite was tested against two bacterial strains, Lactobacillus and Escherichia coli , using the agar disk diffusion technique. The nanocomposites showed excellent antimicrobial activity, producing inhibition zones of 18 mm for Lactobacillus and 19 mm for Escherichia coli , demonstrating their strong potential to combat these bacteria. These findings underscore potential advancements in photocatalytic systems for water purification applications.

Eco-Friendly Fabrication of Porous ZnO Nanostructures Using Araucaria heterophylla Leaf Extract for Catalytic Wastewater Treatment: A Sustainable Approach to Toxic Pollutant Removal

The current investigation documented the construction of eco-friendly zinc oxide nanoparticles (ZnO NPs) using Araucaria heterophylla leaf extract. The synthesized material is characterized through various techniques. The x-ray diffraction (XRD) spectrum depicted prominent diffraction peaks. 31.9 nm was determined to be the average particle size. The spherical and aggregated ZnO NPs were visible in the scanning electron microscope (SEM) results. Energy dispersive x-ray (EDX) spectra results confirmed the existence of Zinc and oxygen elemental peaks. FTIR results of synthesized ZnO NPs and leaf extract elaborated on the participation of phytochemical constituents. Catalytic activity is investigated for Methylene blue (MB) and Congo red dye (CR). For both dyes, the best outcomes are achieved when the dye concentration is 5 mg/L and the adsorbent dose is 10 mg, with a contact duration of 20 min. Adsorption isotherms (Langmuir and Freundlich) and kinetic models including pseudo first order, Elovich, intraparticle diffusion, and Boyd were also applied for dye degradation studies. Antioxidant potential is assessed with three different approaches: total antioxidant, 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity, and total phenolic contents. The scavenging free radical activity percentage was calculated to be 82 ± 0.07 with 1500 μg/mL concentration. In comparison to the standard, total antioxidant activity is 0.569 ± 0.07 (% w/w). While total phenolic contents were 244 ± 1.4 mg GAE/g. Hence, this study demonstrated that biosynthesized ZnO NPs exhibit adequate potential for environmental remediation studies.

Kinetic and Isothermal Analysis of the Adsorptive Elimination of Direct Yellow 26 Dye Utilizing Activated Bioadsorbent From Textile Effluent

Due to their widespread usage in recent years, synthetic dyes may be difficult to remove and pose a health concern. Bioadsorbents proved a low-cost and sustainable method for dye removal. In this study, straight yellow 26 is extracted from textile effluent using sugarcane bagasse. Sugarcane bagasse was treated with propionic acid to enhance the adsorption capability and 0.25 mm particle size was used for further studies which was confirmed by BET analysis. Standard solutions of direct yellow 26 dye were prepared from 10 to 100 ppm concentrations and absorbance was recorded with the help of a UV visible spectrophotometer. After optimizing different parameters (concentration of dye and bioadsorbent dose, pH, time, and particle size), the studies explored that the maximum dye removal percentage was 89% obtained at pH 3, contact time 120 min, particle size 0.25 mm, high adsorbent, and low concentration of dye solution. The kinetic studies were also employed to comprehend the adsorption isotherm and Freundlich isotherm that revealed the pseudo-first-order adsorption process.

E. coli-Assisted Eco-Friendly Production of Biogenic Silver Cobalt Oxide (AgCoO2 ) Nanoparticles: Methanolysis-Based Hydrogen Production, Wastewater Remediation, and Pathogen Control

Herein, bacterial-assisted synthesis of AgCoO2 is carried out. In the first step, E. coli was separated from soil samples via the "serial dilution method." Ten milliliters of bacterial supernatant was mixed with cobalt chloride and silver nitrate hatched at 38°C for 24 h to get AgCoO2 nanoparticles (NPs). XRD results confirm the synthesis of AgCoO2 NPs while EDX results confirm the absence of any other elements than Ag, Co, and O. An average NP size of 12-26 nm was determined by TEM examination, and the surface of the particles was seen rough, irregularly shaped borders. The antibacterial activity of the constructed NPs was checked against S. aureus, E. coli, Bacillus subtilus, and Pseudomanas areguinosa using agar well diffusion method. The maximum zone of inhibition was 27 mm at 40 mg/mL against Bacillus subtilus. The performance of the synthesized NPs as photocatalysts was also assessed, and several operational parameters that control the photodegradation of the harmful dyes were tried to tune as well, and 85% degrading efficiency was obtained at 60oC for 240 min for 30 mg of catalyst dose These NPs were also used to produce hydrogen by methanolysis.

Empowering wastewater treatment with step scheme heterojunction ternary nanocomposites for photocatalytic degradation of nitrophenol

The ongoing challenge of water pollution necessitates innovative approaches to remove organic contaminants from wastewater. In this work, new two-dimensional S-scheme heterojunction photocatalysts Bi2O3/CdS and MoS2/Bi2O3/CdS that are intended for the effective photocatalytic destruction of 4-nitrophenol, a dangerous organic pollutant, are synthesized and characterized. Utilizing a solvothermal method, successfully generated these ternary nanocomposites, which were characterized through various techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), high resolution transmission electronmicroscopy (HRTEM), Brunauer-Emmett-Telle (BET) and diffuse reflectance spectroscopy (DRS). Our results demonstrated that the Bi2O3/CdS heterojunction achieved an 86% degradation rate of 4-nitrophenol, while the MoS2/Bi2O3/CdS composite exhibited exceptional photocatalytic performance, achieving nearly complete degradation (99%) within 120 min under visible light irradiation. Most importantly the improved photocatalytic activity of MoS2/Bi2O3/CdS heterojunction originated from the release of internal electric field in S-scheme heterojunction. This enhanced activity is attributable to the synergistic effects of the heterojunctions that facilitate more effective charge separation and generation with more OP and RP confirmed the composite synthesis using S-scheme. The S-scheme is further confirmed by XPS, DRS, XPS-VB and photocurrent response. These findings highlight the promising application of these advanced photocatalysts in real-world wastewater treatment processes, offering a sustainable solution to combat water pollution.

Novel yellowish-green single-phased spinel Mg1-xBaxAl2O4:Mn2+ phosphor(s) for color rendering white-light-emitting diodes

For white light-rendering research activities, interpretation by using colored emitting materials is an alternative approach. But there are issues in designing the white color emitting materials. Particularly, differences in thermal and decay properties of discrete red, green, and blue emitting materials led to the quest for the search of a single-phased material, able to emit primary colors for white light generation. The current study is an effort to design a simple, single-phase, and cost-effective material with the tunable emission of primary colors by a series of Mg1-xBaxAl2O4:Mn2+ nanopowders. Doping of manganese ion (Mn2+) in the presence of the larger barium cation (Ba2+) at tetrahedral-sites of the spinel magnesium aluminate (MgAl2O4) structure led to the creation of antisite defects. Doped samples were found to have lower bandgaps compared with MgAl2O4, and hybridization of 3d-orbitals of Mn2+ with O(2p), Mg(2s)/Al(2s3p) was found to be responsible for narrowing the bandgap. The distribution of cations at various sites at random results in a variety of electronic transitions between the valance band and oxygen vacancies as well as electron traps produced the antisite defects. The suggested compositions might be used in white light applications since they have three emission bands with centers at 516 nm (green), 464 nm (blue) and 622 nm (red) at an excitation wavelength of 380 nm. A detailed discussion to analyze the effects of the larger cationic radius of Ba2+ on the lattice strain, unit cell parameters, and cell volumes using X-ray diffraction analysis is presented.

Fabrication of Ni/TiO2 visible light responsive photocatalyst for decomposition of oxytetracycline

Nickel-impregnated TiO₂ photocatalyst (NiTP) responding to visible light was prepared by the liquid phase plasma (LPP) method, and its photoactivity was evaluated in degrading an antibiotic (oxytetracycline, OTC). For preparing the photocatalyst, nickel was uniformly impregnated onto TiO₂ (P-25) powder, and the nickel content increased as the number of LPP reactions increased. In addition, the morphology and lattice of NiTP were observed through various instrumental analyses, and it was confirmed that NiO-type nanoparticles were impregnated in NiTP. Fundamentally, as the amount of impregnated nickel in the TiO₂ powder increased sufficiently, the band gap energy of TiO₂ decreased, and eventually, the NiTP excited by visible light was synthesized. Further, OTC had a decomposition reaction pathway in which active radicals generated in OTC photocatalytic reaction under NiTP were finally mineralized through reactions such as decarboxamidation, hydration, deamination, demethylation, and dehydroxylation. In effect, we succeeded in synthesizing a photocatalyst useable under visible light by performing only the LPP single process and developed a new advanced oxidation process (AOP) that can remove toxic antibiotics.

Semiconductor-metal-semiconductor TiO2@Au/g-C3N4 interfacial heterojunction for high performance Z-scheme photocatalyst

We designed an edge-sites 2D/0D/2D based TiO2@Au/g-C3N4 Z-scheme photocatalytic system consists of highly exposed (001) TNSs@Au edge-site heterojunction, and the Au/g-C3N4 interfacial heterojunction. The designed photocatalyst was prepared by a facile and controlled hydrothermal synthesis strategy via in-situ nanoclusters-to-nanoparticles deposition technique and programable calcination in N2 atmosphere to get edge-site well-crystalline interface, followed by chemically bonded thin overlay of g-C3N4. Photocatalytic performance of the prepared TNSs@Au/g-C3N4 catalyst was evaluated by the photocatalytic degradation of organic pollutants in water under visible light irradiation. The results obtained from structural and chemical characterization conclude that the inter-facet junction between highly exposed (001) and (101) TNSs surface, and TNSs@Au interfacial heterojunction formed by a direct contact between highly crystalline TNSs and Au, are the key factors to enhance the separation efficiency of photogenerated electrons/holes. On coupling with overlay of g-C3N4 2D NSs synergistically offer tremendous reactive sites for the potential photocatalytic dye degradation in the Z-scheme photocatalyst. Particularly in the designed photocatalyst, Au nanoparticles accumulates and transfer the photo-stimulated electrons originated from anatase TNSs to g-C3N4via semiconductor-metal heterojunction. Because of the large exposed reactive 2D surface, overlay g-C3N4 sheets not only trap photoelectrons, but also provide a potential platform for increased adsorption capacities for organic contaminants. This work establishes a foundation for the development of high-performance Z-scheme photocatalytic systems.

Coupling Long-Range Facet Junction and Interfacial Heterojunction via Edge-Selective Deposition for High-Performance Z-Scheme Photocatalyst

The construction of photocatalytic systems that have strong redox capability, effective charge separation, and large reactive surfaces is of great scientific and practical interest. Herein, an edge-connected 2D/2D Z-scheme system that combines the facet junction and the interfacial heterojunction to achieve effective long-range charge separation and large reactive surface exposure is designed and fabricated. The heterostructure is realized by the selective growth of 2D-layered MoS2 nanoflakes on the edge-sites of thin TiO2 nanosheets via an Au-promoted photodeposition method. Attributed to the synergetic coupling of the facet junction and the interfacial heterojunction that assures the effective charge separation, and the tremendous but physically separated reactive sites offered by layered MoS2 and highly-exposed (001) facets of TiO2 , respectively, the artificial Z-scheme exhibits excellent photocatalytic performance in photodegradation tests. Moreover, the junctional plasmonic Au nanoclusters not only act as electron traps to promote the edge-selective synthesis but also generate "hot electrons" to further boost photocatalytic performance. The Z-scheme charge-flow direction in the heterostructure and the roles of electrons and holes are comprehensively studied using in situ irradiated X-ray photoelectron spectroscopy and photodegradation tests. This work offers a new insight into designing high-performance Z-scheme photocatalytic systems.

Facile preparation of bismuth vanadate-sheet/carbon nitride rod-like interface photocatalyst for efficient degradation of model organic pollutant under direct sunlight irradiation

The photocatalytic performance of a semiconducting catalytic system is strongly influenced by charge-carrier separation rate, charge transport properties, surface area, utilization of light energy, and interface bonding. Herein, a series of bismuth vanadate (BiVO₄) samples were prepared via hydrothermal method by changing the volume ratios of ethelene glycol and ethanol as a solvent mixture for bismuth precursors. Further, the optimized BiVO₄ sheets with hierarchical morphology were used to construct an interface with rod-like g-C₃N₄ materials, which was confirmed by HRSEM and HRTEM. Due to the formation of an effective interface bonding between BiVO₄/g-C₃N₄, the photoinduced charge carrier's recombination rate was suppressed as confirmed by the PL analysis. The prepared BiVO₄/g-C₃N₄ sample were used to assess the photodegradation efficiency of Rhodamine B (RhB) under direct sunlight irradiation and the photocatalysts degraded ~92.8% of RhB within 2 h. The TOC measurements revealed a 66.4% mineralization efficiency for RhB. In addition, the radical trapping experiments demonstrated that superoxide and hydroxyl radicals are the main reactive species for the degradation. Based on the experimental evidences, a plausible charge transfer mechanism has been proposed. The enhanced photocatalytic activity has been mainly attributed to the inhibition of the recombination rate, enhanced charge carrier transfer efficiency, and high rate of production of reactive species.

Significant Aggregation-Enhanced Carrier Separation in Nanoscopic Catalysts Heterojunction Stacks

Nanoscopic heterojunction stacks are prevalent in nature as well as in artificial material systems, such as the nanoscopically blended components in soil or artificial catalytic layers on device surfaces. Despite the enormous attention placed on studying individual heterojunctions, the advantageous catalytic performance of heterojunction aggregates has not been recognized. In this study, we employ the ordered N-doped TiO₂ nanosheets and Au nanoparticle heterojunction multilayers obtained by a layer-by-layer technique to investigate the functional merits stemmed from heterojunction aggregates. The study demonstrates that nanoscopic heterojunction stacks promote the internal electric field that stemmed from charge separation and boost carrier separations. The aggregate-enhanced carrier separation can be harnessed in chemical conversions. The enhancement effect is influenced by both the dimensions of the entire aggregates as well as the dimensions of the nanoscopic building units. We expect the study to promote the understanding of heterojunction catalysts and corresponding matter conversion from the individual particulate level to the nanoscopic aggregate level and facilitate better harnessing of the photovoltaic effects or catalytic power in nanoscopic heterojunction aggregates.

Iron and chromium co-doped cobalt phosphide porous nanosheets as robust bifunctional electrocatalyst for efficient water splitting

It is still a huge challenge to develop highly efficient and low-cost non-precious metal-based electrocatalysts for overall water splitting in alkaline electrolytes. Herein, Cr and Fe co-doped CoP porous mesh nanosheets (Mesh-CrFe-CoP NSs) were synthesized through hydrolysis reaction, ion exchange etching and subsequent low-temperature phosphating process. The Mesh-CrFe-CoP NSs provides overpotentials at a current density of 10 mA cm^-2under alkaline electrolyte of 103.7 mV and 256.4 mV for HER and OER, respectively. Furthermore, when using Mesh-CrFe-CoP NSs as anode and cathode, the water splitting system could afford a current density of 10 mA cm^-2at 1.55 V, which is better than an electrolytic cell composed of 20% Pt/C and RuO₂. The excellent electrocatalytic performance of Mesh-CrFe-CoP NSs is attributed to the co-doping and porous nanostructure. Specifically, the Cr and Fe co-doped porous CoP nanosheets electrocatalyst not only provided abundant exposure active sites, accelerated the entry of liquid and the diffusion of gas, but also regulated the electronic environment of active sites, and thus enhanced the electrochemical performance. This work proposes a strategy for the rational design of highly efficient and stable non-precious metal co-doped phosphide electrocatalysts in the of electrochemical water splitting.

A facile synthesis of nano AgBr attached potato-like Ag2MoO4 composite as highly visible-light active photocatalyst for purification of industrial waste-water

In recent times, silver (Ag) based semiconductors have been gained a lot of attention as photocatalysts for industrial waste-water treatment owing to their strong visible-light absorbing capability and small bandgap energy. Therefore, herein, we have designed and utilized a one-pot hydrothermal approach to the synthesis of nano-sized AgBr covered potato-like Ag₂MoO₄ composite photocatalysts for the elimination of organic wastes from the aquatic environment. To achieve a high-performance photocatalyst, a sequence of AgBr/Ag₂MoO₄ composites were acquired with varying CTAB from 1 to 4 mmol. Furthermore, the photocatalytic activity of these photocatalysts was confirmed from decomposing of Rhodamine B (RhB) dye via visible-light elucidation. It can be noticed that AgBr/Ag₂MoO₄ composites exhibited significantly increased photocatalytic behaviour as compared with pure AgBr and Ag₂MoO₄. Surprisingly, the AgBr/Ag₂MoO₄ composite obtained from 2 mmol CTAB was eliminated the entire RhB dye with 25 min. Also, the recycling experiment indicates the AgBr/Ag₂MoO₄ composite has an excellent photo-stability. Accordingly, the as-acquired AgBr/Ag₂MoO₄ composite would be a suitable photocatalytic material for industrial waste-water purification.

Bifunctional nanoporous Ni-Zn electrocatalysts with super-aerophobic surface for high-performance hydrazine-assisted hydrogen production

In the present study, an effective approach is proposed to replace the oxygen evolution reaction with the substituted anodic hydrazine oxidation reaction (HzOR) to assist in hydrogen generation based on a bifunctional porous Ni-Zn electrocatalyst with nanosheet arrays. The Ni-Zn catalyst exhibits an extraordinary HzOR performance with a high current density of 970 mA cm^-2 at 0.7 V, and 93.8% of its initial activity after 5000 s, simultaneously delivering an overpotential of 68 mV at 10 mA cm^-2 for the hydrogen evolution reaction. Moreover, the electrolytic cell is constructed employing Ni-Zn catalysts as both the anode and cathode, achieving 100 mA cm^-2 at an ultralow cell voltage of 0.497 V with an outstanding stability over 10 h. The superior electrocatalytic performance can be ascribed to its porous structure with large active surface area, high electrical conductivity, and most importantly the super-aerophobic nature of the Ni-Zn surface. This work also provides a novel approach to designing and constructing porous structured non-noble metal bifunctional electrocatalysts with super-aerophobic surface to be used for energy-saving hydrogen production.

Tailoring hollow structure within NiCoP nanowire arrays via nanoscale Kirkendall diffusion to enhance hydrogen evolution reaction

Hollow structured nanomaterials with void space available inside the shells can effectively enhance electrocatalytic activity due to their high specific surface area, volume buffer and shell permeability properties. In this study, low-cost and hollow structured bimetal phosphide nanowires are synthesized directly on Ni foam via the Kirkendall effect by using NaH2PO2 as a phosphorizing agent at 350 °C. Both the crystal and hollow structures of the obtained phosphide can be efficiently tuned by controlling the amount of phosphorizing agent and the phosphorizing time. The morphology and microstructure of the obtained phosphides are characterised using various techniques, which indicate that the formation mechanism of the hollow structure is consistent with the Kirkendall effect. The optimized bimetal phosphide sample demonstrates a low onset potential (59 mV) at a current density of 10 mA cm-2, low charge transfer resistance (0.83 Ω) and superior durability in the hydrogen evolution reaction (HER) for water electrolysis. The electrochemical results clearly demonstrate that the hollow structure can efficiently improve the HER properties and the obtained phosphide is a promising HER catalysts for water splitting in KOH or seawater electrolytes.

Structurally and Compositionally Tunable Absorption Properties of AgCl@AgAu Nanocatalysts for Plasmonic Photocatalytic Degradation of Environmental Pollutants

Composite nanomaterials having Ag nanoparticles (NPs) that decorate nanostructured AgCl (Ag/AgCl) are promising as plasmonic photocatalysts because of the visible-light absorption of Ag NPs. However, the narrow absorption bands of Ag NPs near 400 nm cause inefficient absorption in the visible range and, consequently, unsatisfactory photocatalytic activity of Ag/AgCl nanomaterials. In this study, we introduce a new class of AgCl-based photocatalysts that are decorated with bimetallic Ag and Au NPs (AgCl@AgAu NPs) for visible-light-driven photocatalytic degradation of organic pollutants. Polyvinylpyrrolidone induces selective reduction of noble metal precursors on AgCl while leaving AgCl intact. The extended composition of the decorating NPs red-shifts the absorption band to 550–650 nm, which allows the catalysts to take advantage of more energy in the visible range for improved efficiency. Furthermore, we control the structures of the AgCl@AgAu NPs, and investigate their correlation with photocatalytic properties. The versatility, chemical stability, and practical application of the AgCl@AgAu NPs are demonstrated using various organic pollutants, recycling experiments, and natural aqueous media, respectively. Our fundamental investigation on the synthesis and applications of AgCl-based nano-photocatalysts is highly valuable for designing plasmonic photocatalysts and expanding their utilization.

Improved figures of merit of nano-Schottky diode by embedding and characterizing individual gold nanoparticles on n-Si substrates

Improving Schottky diode characteristics in semiconducting devices is essential for better functionality in electronic and optoelectronic devices at nanoscale. In this paper, we investigate the electric transport characteristics of a gold (Au)-tip/n-Si-based nano-Schottky diode by using a conductive-mode atomic force microscope (CAFM). First, 10 nm average diameter Au nanoparticles (NPs) are monodispersed on the highly cleaned n-type Si substrate using an optimized spin-coating technique. The controlled and well dispersed NPs are confirmed by using the AC imaging mode of the AFM. The electrical characteristics are established by using an Au-coated AFM tip, by either soft engaging at the surface of the n-Si substrate or at the top of an individual Au NP. Landing of the AFM tip on the NP or n-Si substrate is validated by the force curves of the AFM. From the localized CAFM electrical characteristics, we observed the improvement in the figures of merit (FOM) that characterize the rectification performance including the (1-V) asymmetry (f _ASYM), and the turn-on voltage due to placing the Au NP between the AFM tip and n-Si substrate. These improved FOM of the nanoscale diodes are explained based on the increase in the tunneling current at the nanoscale Au-NP/n-Si interface. Moreover, the nanoscale control of interface structure is extremely important to improve the characteristics of nano-Schottky diodes.

Time dependence of electrical characteristics during the charge decay from a single gold nanoparticle on silicon

In this work, we investigate the time dependence of trapped charge in isolated gold nanoparticles (Au-NPS) dispersed on n-Si substrates, based on the electrical characteristics of nano metal–semiconductor junctions. The current–voltage (I–V) characteristics have been analysed on a single Au-NP at different time intervals, using conductive mode atomic force microscopy (AFM). The Au-NPs have been characterized for their morphology and optical properties using transmission electron microscopy (TEM), ultraviolet visible (UV-vis) spectroscopy and scanning electron microscopy (SEM). The tunneling current is found to be a direct function of the trapped charge in the NP, due to the charge screening effect of the electric field at the NP/n-Si interface. The evolution of the I–V curves is observed at different time intervals until all the trapped charge dissipates. Moreover, the time needed for nanoparticles to restore their initial state is verified and the dependence of the trapped charge on the applied voltage sweep is investigated.

In this work, we investigate the time dependence of trapped charge in isolated gold nanoparticles (Au-NPS) dispersed on n-Si substrates, based on the electrical characteristics of nano metal–semiconductor junctions.

Designing novel morphologies of l-cysteine surface capped 2D covellite (CuS) nanoplates to study the effect of CuS morphologies on dye degradation rate under visible light

Novel CuS@l-Cys NPs are designed by a hydrothermal route. The effects of synthetic parameters on the morphologies of CuS@l-Cys NPs were investigated. CuS@l-Cys NPs exhibit an enhanced dye degradation rate under visible light.