- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Detoxification of dye contaminated water by Mn $$^{2+}$$ 2 + -doped ZnS nanostructures
摘要： Chemical co-precipitation route was successfully employed to synthesize polyethylene glycol-coated pure and doped Zn1?x Mnx S (0 ≤ x ≤ 0.1) nanoparticles. The crystallographic and morphological analyses have been done by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The formation of cubic crystal structure and quasi-spherical morphology has been revealed by XRD and TEM, respectively. The optical analyses have been done by UV–Vis absorption spectroscopy and energy resolved photoluminescence spectroscopy. Energy dispersive X-ray spectroscopy study has been carried to analyse the elemental composition. The doping concentration dependent photo-catalytic activity was checked to analyse the photo-catalytic potential of Zn1?x Mnx S nanoparticles under UV irradiation.
关键词： photo-catalytic activity,Chemical co-precipitation,Zn1?x Mnx S nanoparticles
更新于2025-11-14 15:26:12
-
Ternary Ag nanoparticles/natural-magnetic SiO2-nanowires/reduced graphene oxide nanocomposites with highly visible photocatalytic activity for 4-nitrophenol reduction
摘要： Agglomerate and reuse limit the promising application of silver nanoparticles (AgNPs) as catalyst. To eliminate those disadvantages, herein, Fe-containing silica nanowires (SiO2NWs) and reduced graphene oxide (RGO) are used as suitable substrates to prepare AgNPs/SiO2NWs/RGO nanocomposite via self-assembly approach. The nanocomposite mostly assembled with each other via intermolecular hydrogen bond and electrostatic adsorption to form a three-dimensional network structure. The AgNPs/SiO2NWs/RGO nanocomposite exhibit excellent photocatalytic activity for 4-nitrophenol reduction by NaBH4, originating from that the nearly mono-dispersed AgNPs are adhered on the surface of the SiO2NWs and RGO, allowing the effective contact of reactants with catalyst and facilitating the electron transfer between them in the reaction. The obtained nanocomposites exhibit the superior stability and can be easily recovered with their fully catalytic activities due to the hydrophobic and magnetic properties of the nanocomposites. It shows the great prospect for the 4-NP reduction in practice and is promising for wide applications in visible light catalytic reaction.
关键词： SiO2 nanowires,Photo-catalytic activity,Reduced graphene oxide,Silver nanoparticles,4-Nitrophenol reduction
更新于2025-09-23 15:22:29
-
Density Functional Theory Calculations of Oxygen-Vacancy Formation and Subsequent Molecular Adsorption on Oxide Surfaces
摘要： The surface oxygen vacancy formation energy (EOvac) is an important parameter in determining the catalytic activity of metal oxides. Estimating these energies can therefore lead to data-driven design of promising catalyst candidates. In the present study, we determine EOvac for various insulating and semiconducting oxides. Statistical investigations indicate that the band gap, bulk formation energy, and electron affinity are factors that strongly influence EOvac. Electrons enter defect states after O desorption, and these states can be in the valence band, mid-gap, or in the conduction band. Subsequent adsorption of O2, NO, CO, CO2, and H2 molecules on an O-deficient surface is also investigated. These molecules become preferentially adsorbed at the defect sites, and EOvac is identified as the dominant factor that determines the adsorption mode as well as a descriptor that shows good correlation with the adsorption energy.
关键词： catalytic activity,molecular adsorption,oxygen vacancy formation energy,metal oxides,density functional theory
更新于2025-09-23 15:21:21
-
Optical Control of Biomimetic Nanoparticle Catalysts Based Upon the Metal Component
摘要： Nanoparticle catalysts provide an intriguing route to achieving sustainable reactivity. Recent evidence has suggested that both the underlying metallic core and the passivating ligand layer can be exploited to control reactivity. The intimate interactions between the core metal and structure of the ligand layer can change based upon the metal used to generate the catalytic particle. Through judicious selection of both components, nanoparticle catalytic systems can be designed to be stimuli responsive for controlled reactivity. Herein we demonstrate the effects of the underlying metal on the optically modulated catalytic activity of peptide-capped noble metal nanoparticles. For this, a photoswitch was incorporated into the peptide that enables reversible reconfiguration of the bioligand overlayer structure between two conformations based upon the isomerization state of the photoswitch. These changes in activity are dependent upon the inorganic metal of the particle core, and we exploit this dependence to demonstrate changes in the activity. The materials were fully characterized via spectroscopic methods and microscopy to correlate the observed reactivity to the material composition. The results provide new pathways to achieve remotely responsive catalysts that could be important for controlled multistep reactions or be exploited for other applications including biosensing and plasmonic devices.
关键词： optically modulated catalytic activity,peptide-capped noble metal nanoparticles,biosensing,Nanoparticle catalysts,photoswitch,plasmonic devices
更新于2025-09-23 15:21:21
-
A Unique Pair: Ag40 and Ag46 Nanoclusters with the Same Surface but Different Cores for Structure-Property Correlation
摘要： Understanding the optical properties of nanoclusters is one of the central tasks in fundamental research. In this work, two new Ag nanoclusters that have distinctly different cores but a common protecting shell are [Ag40(2,4-DMBT)24(PPh3)8] and [Ag46(2,5-DMBT)24(PPh3)8]2+. Significantly, the Ag40 nanocluster comprises a simple cubic core of Ag8, which is for the first time observed experimentally. Using the Ag40 and Ag46 nanoclusters as a unique pair, we have investigated the effect of core structure on the optical absorption properties of these nanoclusters. The compact core-shell in Ag46 makes the frontier orbitals highly degenerate, whereas the loose core-shell of Ag40 leads to much less degeneracy in the frontier orbits. Also, with the difference in the core structure, these two silver nanoclusters show different catalytic activity in the oxygen reduction reaction. Overall, this work reveals that the core packing mode plays a significant role in determining the optical of metal nanoclusters. The new materials with controlled crystalline phases also hold promise in other applications.
关键词： Ag nanoclusters,crystalline phases,core structure,optical properties,catalytic activity
更新于2025-09-23 15:21:01
-
Kinetic Map for Destabilization of Pt-Skin Au Nanoparticles via Atomic Scale Rearrangements
摘要： A commonly used strategy to enhance the mass activity of Pt-based catalysts involves the synthesis of Au nanoparticles (NPs) with a monolayer-thick Pt-skin layer. The synergistic effect of Au and Pt results in a higher catalytic activity and better Pt utilization. However, the stability of the Pt-skin layer is questionable as our recent equilibrium Monte Carlo simulations predict that eventually the surface Pt is replaced by Au. The role of Au during destabilization of Pt-skin in vacuum and solution is investigated with the help of molecular dynamics. Different starting Au?Pt arrangements are studied mimicking various NP synthesis approaches. Beyond a critical number of atoms in a Pt cluster, the ideal Pt monolayer rapidly transforms to a three-dimensional (3D) Pt cluster. This is supported by our model predicting transition from the Pt monolayer to Volmer?Weber growth in the Au?Pt system. At room temperature, Pt atoms move into the subsurface layer at second timescales mainly via the exchange mechanism involving Au atoms or Au climbing on top of Pt. For all practical purposes, the experimental “Pt-skin” Au NPs may actually correspond to a single layer of surface Au over subsurface Pt layers. Presence of large 3D Pt clusters may slowdown the climbing of Au atoms on Pt, thereby delaying the formation of Au-skin.
关键词： Pt-skin,Au nanoparticles,destabilization,catalytic activity,molecular dynamics
更新于2025-09-23 15:21:01
-
Silver modified cadmium oxide - A novel material for enhanced photodegradation of malachite green
摘要： An enhancement of Cadmium oxide (CdO) based catalyst activity was observed on modification with silver (Ag) by hydrothermal route in a short time and at low temperature. The products were characterized by XRD, Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD confirming the formation of CdO showed an intense diffraction peak at 32.73° with lattice plane (111). The IR spectrum shows characteristic peaks at 607, 1387 cm-1 corresponding to Cd-O bonds. Both CdO and Ag modified CdO (Ag-CdO) showed band gaps of 2.76 eV and 2.56 eV respectively stretching into the red portion of the solar spectrum. On irradiation with Ultraviolet (Uv) light CdO-Ag showed 78.02 % degradation of malachite green oxalate (MG), a hazardous dye within 175 minutes in comparison to native CdO (75.85 % in 175 minutes). Photoluminescence (PL) studies demonstrated better emission intensity quenching in case of Ag-CdO which is particularly promising for photocatalytic applications.
关键词： catalytic activity,semiconductor,luminescence,nanostructure
更新于2025-09-23 15:21:01
-
The Optical Properties and Photo catalytic Activity of ZnS-TiO2/Graphite Under Ultra Violet and Visible Light Radiation
摘要： This paper discuss research about the optical properties and photo catalytic activity of TiO2 film on graphite substrate and its modification with ZnS. The optical properties investigated are the light response at various light wavelength and the gap energy (Eg). Meanwhile, the photocatalytic activity was studied from isopropanol degradation to determine the Quantum Yield (QY) and kinetics of reaction. The results show that the TiO2 layer is consisted of rutile and anatase phases. Meanwhile, the ZnS peaks are at 2θ 27.91o and 54.58o. The gap energy of TiO2/G consist of two band gap represent- ing the band gap of rutile and anatase. The ZnS deposition shifted the band gap into single gap of 3.40 eV which is in between the gap energy of single TiO2 and single ZnS. The isopropanol degradation with TiO2/G photocatalyst under visible light radiation did not produce any new peaks representing product. Meanwhile, the photocatalytic process under 380 nm light produce new peaks representing the elec- tronic transition of acetone. The isopropanol degradation with ZnS-TiO2/Graphite produced new peaks that indicates the photocataytic activity of ZnS-TiO2/Graphite whether under UV or visible light radia- tion. Significant role of ZnS also proven by the increase of the QY values and the increase of rate con- stant, k. ? 2015 BCREC UNDIP. All rights reserved.
关键词： photo catalytic activity,ZnS,chemical bath deposition,TiO2,composite
更新于2025-09-23 15:19:57
-
Artificial tailored catalytic activity for identification of 6 kinds of volatile organic compounds via the light-regulated electrochemical reaction
摘要： Light-regulated electrochemical reaction is confirmed to be useful to improve the classification efficiency. However, the use of different photoactive sensing materials results in time-consuming for exploring well-designed materials, besides, the light-regulated electrochemical reaction only improved the classification feature while didn't bring essential difference in the distinguish capability yet. Herein, a zirconia-based electrochemical sensor array comprised of 3 types of ZnO/In2O3 composite sensing materials is fabricated. After illumination, significantly enhancement is witnessed for the response magnitude and detection limit. Additionally, the response signal of the sensor array to part of the examined volatile organic compounds (VOCs) is selectively enhanced and 3 more disparate response patterns are generated. Through inputting all the response patterns into principle component analysis (PCA) software, 6 kinds of concerned VOCs have been fully classified. Conclusively, with utilizing sensing materials with similar composition, the fabrication process of the sensor array can be simplified. Particularly, after exposure to illumination the sensor array consisting of limited photoactive sensing materials (e.g. 3 kinds of materials) can identify even more number of gases (e.g. 6 types of VOCs). We anticipate these promising results shed light on the bright future of designing compact sensing devices for progressively smarter monitoring of concerned gas species.
关键词： Principle component analysis,Light-regulated electrochemical reaction,Volatile organic compounds,Response patterns,Artificial tailored catalytic activity,Zirconia-based sensor array
更新于2025-09-19 17:15:36
-
Robot path planning with two-axis positioner for non-ideal sphere-pipe joint welding based on laser scanning
摘要： The conversion and degradation of organic pollutants remain challenges relating to environmental science. Herein, we report the carbonization of organic pollutants (4-nitrophenol, 4-NP) toward metal-free nitrogen-doped graphene quantum dots (N-GQDs) using a one-pot solvothermal route. The resultant N-GQDs demonstrate excellent activity for the catalytic conversion of 4-NP to 4-aminophenol (4-AP) when exposed to near infrared (NIR) light because of their excellent upconverted photoluminescence and photothermal conversion ability. The NIR-enhanced reduction efficiency of 4-NP to 4-AP not only originates from the enhanced collisions between N-GQDs and 4-NP due to photothermal-increased Brownian movement of molecules, but also comes from the accelerated transfer rate of electrons produced by the photoexcitation of N-GQDs under NIR irradiation. The N-GQDs display excellent photostability and remain high activity even after five cycles of reuse. Such conversion of organic pollutants to highly efficient metal-free carbocatalysts has significant importance in relevance of the industrial production of aniline and paracetamol.
关键词： organic pollutants,metal-free photocatalysts,4-nitrophenol reduction,nitrogen-doped graphene quantum dots,NIR-enhanced catalytic activity
更新于2025-09-19 17:13:59