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Multi-functional MnO <sub/>2</sub> nanomaterials for photo-activated applications by a plasma-assisted fabrication route
摘要： Supported MnO2-based nanomaterials were fabricated on fluorine-doped tin oxide substrates using plasma enhanced-chemical vapor deposition (PE-CVD) between 100 °C and 400 °C, starting from a fluorinated Mn(II) diamine diketonate precursor. Growth experiments yielded β-MnO2 with a hierarchical morphology tuneable from dendritic structures to quasi-1D nanosystems as a function of growth temperature, whose variation also enabled a concomitant tailoring of the system fluorine content, and of the optical absorption and band gap. Preliminary photocatalytic tests were aimed at the investigation of photoinduced hydrophilic (PH) and solid phase photocatalytic (PC) performances of the present nanomaterials, as well as at the photodegradation of Plasmocorinth B azo-dye aqueous solutions. The obtained findings highlighted an attractive system photoactivity even under visible light, finely tailored by fluorine content, morphological organization and optical properties of the prepared nanostructures. The results indicate that the synthesized MnO2 nanosystems have potential applications as advanced smart materials for anti-fogging/self-cleaning end uses and water purification.
关键词： anti-fogging,photoactivated applications,fluorine doping,photocatalysis,water purification,self-cleaning,plasma-assisted fabrication,MnO2 nanomaterials
更新于2025-09-19 17:15:36
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - L-Band Amplifiers Based on Cladding-Pumped Er-Doped (Yb-Free) Fibers with Al <sub/>2</sub> O <sub/>3</sub> -SiO <sub/>2</sub> Core Highly Doped by Fluorine
摘要： Recently we have demonstrated perspectives of application double clad (DC) highly Er-doped (Yb-free) fibers for pulse amplification to a record-high energy and peak power [1]. Single-mode propagation regime, high pump-to-signal conversion efficiency (PCE) of 25% in L-band (near 1575 nm) and a relatively short fiber length (~ 6 m) was achieved by optimization of fiber geometry and core compound. Core-to-cladding ratio was chosen as high as possible (core and cladding diameters were 35 (cid:80)m and 125 (cid:80)m correspondingly) to increase pump absorption from the cladding. Utilization of P2O5-Al2O3-SiO2 (PAS) glass matrix [2] allowed us to achieve a low core numerical aperture (NA) and, simultaneously, high PCE even for heavily Er-doped fibers.
关键词： L-band amplifiers,Fluorine doping,Er-doped fibers,Al2O3-SiO2 core,Pump-to-signal conversion efficiency
更新于2025-09-11 14:15:04
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Impact of the anodization time on the photocatalytic activity of TiO <sub/>2</sub> nanotubes
摘要： Titanium oxide nanotubes (TNTs) were anodically grown in ethylene glycol electrolyte. The influence of the anodization time on their physicochemical and photoelectrochemical properties was evaluated. Concomitant with the anodization time, the NT length, fluorine content, and capacitance of the space charge region increased, affecting the opto-electronic properties (bandgap, bathochromic shift, band-edge position) and surface hydrophilicity of TiO2 NTs. These properties are at the origin of the photocatalytic activity (PCA), as proved with the photooxidation of methylene blue.
关键词： nanotubes,photocatalytic activity,photoelectrochemistry,titanium(IV) oxide (TiO2),fluorine doping
更新于2025-09-10 09:29:36
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Enhanced visible-light-driven photocatalytic activity of F doped reduced graphene oxide - Bi <sub/>2</sub> WO <sub/>6</sub> photocatalyst
摘要： The reduced graphene oxide‐Bi2WO6 (rGO‐BWO) photocatalysts with the different RF/O values (molar ratio of the F molar mass and the O's molar mass of Bi2WO6) had been successfully synthesized via one‐step hydrothermal method. The F‐doped rGO‐BWO samples were characterized by X‐ray diffraction patterns (XRD), field‐emission scanning electron microscopy (FE‐ESEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller surface area (BET), X‐ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (DRS). The results indicate that F ions had been successfully doped into rGO‐BWO samples. With the increasing of the RF/O values from 0 to 2%, the evident change of the morphology and the absorption edges of F‐doped rGO‐BWO samples and the photocatalytic activities had been enhanced. Moreover, the photocatalytic activity of F‐doped rGO‐BWO with RF/O = 0.05 were better than rGO‐BWO and the other F‐doped rGO‐BWO under 500 W Xe lamp light irradiation. The enhanced photocatalytic activity can be attributed to the morphology of the intact microsphere that signify the bigger specific surface area for providing more possible reaction sites for the adsorption–desorption equilibrium of photocatalytic reaction, the introduction of F ions that may cause the enhancement of surface acidity and creation of oxygen vacancies under visible light irradiation, the narrower band gap which means needing less energy for the electron hole pair transition.
关键词： photocatalytic activity,rGO‐Bi2WO6,fluorine doping,hydrothermal method
更新于2025-09-10 09:29:36
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XPS investigation of F-doped MnO <sub/>2</sub> nanosystems fabricated by plasma assisted-CVD
摘要： Supported Mn(IV) oxide nanomaterials were prepared by plasma assisted-chemical vapor deposition from Ar/O2 plasmas starting from a fluorinated Mn(II) β-diketonate diamine adduct. Under the adopted conditions, the target compound served as a single-source molecular precursor for the obtainment of MnO2 nanosystems uniformly doped with fluorine. The overall F content in the target materials, composed of phase-pure β-MnO2, could be tailored as a function of the deposition temperature from 100 to 400 °C, a result of particular importance in view of photocatalytic and gas sensing applications. In the present study, attention is specifically devoted to the investigation of a representative specimen by means of x-ray photoelectron spectroscopy. Besides the wide scan spectrum, a detailed analysis of C 1s, O 1s, Mn 2p, Mn 3s, and F 1s photoelectron peaks is presented and discussed. The analyses reveal the formation of MnO2 free from other manganese oxides, with fluorine present in different chemical states, i.e., lattice F plus traces of precursor residuals at the system surface.
关键词： fluorine doping,x-ray photoelectron spectroscopy,PA-CVD,manganese oxide
更新于2025-09-04 15:30:14