Facile method to synthesize magnetic iron oxides/TiO2 hybrid nanoparticles and their photodegradation application of methylene blue

Many methods have been reported to improving the photocatalytic efficiency of organic pollutant and their reliable applications. In this work, we propose a facile pathway to prepare three different types of magnetic iron oxides/TiO2 hybrid nanoparticles (NPs) by seed-mediated method. The hybrid NPs are composed of spindle, hollow, and ultrafine iron oxide NPs as seeds and 3-aminopropyltriethyloxysilane as linker between the magnetic cores and TiO2 layers, respectively. The composite structure and the presence of the iron oxide and titania phase have been confirmed by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectra. The hybrid NPs show good magnetic response, which can get together under an external applied magnetic field and hence they should become promising magnetic recovery catalysts (MRCs). Photocatalytic ability examination of the magnetic hybrid NPs was carried out in methylene blue (MB) solutions illuminated under Hg light in a photochemical reactor. About 50% to 60% of MB was decomposed in 90 min in the presence of magnetic hybrid NPs. The synthesized magnetic hybrid NPs display high photocatalytic efficiency and will find recoverable potential applications in cleaning polluted water with the help of magnetic separation

Preparation and characterization of spindle-like Fe3O4 mesoporous nanoparticles

Magnetic spindle-like Fe3O4 mesoporous nanoparticles with a length of 200 nm and diameter of 60 nm were successfully synthesized by reducing the spindle-like α-Fe2O3 NPs which were prepared by forced hydrolysis method. The obtained samples were characterized by transmission electron microscopy, powder X-ray diffraction, attenuated total reflection fourier transform infrared spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and nitrogen adsorption-desorption analysis techniques. The results show that α-Fe2O3 phase transformed into Fe3O4 phase after annealing in hydrogen atmosphere at 350°C. The as-prepared spindle-like Fe3O4 mesoporous NPs possess high Brunauer-Emmett-Teller (BET) surface area up to ca. 7.9 m2 g-1. In addition, the Fe3O4 NPs present higher saturation magnetization (85.2 emu g-1) and excellent magnetic response behaviors, which have great potential applications in magnetic separation technology

Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment

Funding Information: This work was supported by the National Natural Science Foundation of China under grant 11875210, the Science and Technology Planning Project of Guangdong Province under grant 2018A050506082, China Postdoctoral Science Foundation under grant 2019M652687, and by the grant RFBR No.19-05-00554 in the part of the development of advanced approach to analysis of geochemical objects.In the present study Ar+ cluster ions accelerated by voltages in the range of 5-10 kV are used to irradiate single crystal ZnO substrates and nanorods to fabricate self-assembled surface nanoripple arrays. The ripple formation is observed when the incidence angle of the cluster beam is in the range of 30-70°. The influence of incidence angle, accelerating voltage, and fluence on the ripple formation is studied. Wavelength and height of the nanoripples increase with increasing accelerating voltage and fluence for both targets. The nanoripples formed on the flat substrates remind of aeolian sand ripples. The ripples formed at high ion fluences on the nanorod facets resemble well-ordered parallel steps or ribs. The more ordered ripple formation on nanorods can be associated with the confinement of the nanorod facets in comparison with the quasi-infinite surface of the flat substrates.publishersversionpublishe

Regulation of Two-Dimensional Lattice Deformation Recovery

The lattice directly determines the electronic structure, and it enables controllably tailoring the properties by deforming the lattices of two-dimensional (2D)materials. Owing to the unbalanced electrostatic equilibrium among the dislocated atoms, the deformed lattice is thermodynamically unstable and would recover to the initial state. Here, we demonstrate that the recovery of deformed 2D lattices could be directly regulated via doping metal donors to reconstruct electrostatic equilibrium. Compared with the methods that employed external force fields with intrinsic instability and nonuniformity, the stretched 2D molybdenum diselenide (MoSe2)could be uniformly retained and permanently preserved via doping metal atoms with more outermost electrons and smaller electronegativity than Mo. We believe that the proposed strategy could open up a new avenue in directly regulating the atomic-thickness lattice and promote its practical applications based on 2D crystals. © 2019 The Author(s

Fabrication of TiO 2

The TiO2 photoelectrodes fabricated on the substrate of Ti foils by Ti ions implantation and subsequent annealing at different temperatures were applied for water splitting. The size of TiO2 nanoparticles increased with annealing temperatures, and the GIXRD patterns and Raman spectra demonstrate that the phase of TiO2 turns to rutile at high temperature. The photoelectrochemical (PEC) and X-ray photoelectron spectroscopy (XPS) spectra of the valence band demonstrate that the samples annealed at 400 and 500°C show the n-type property. The sample annealed at 600°C shows the weak p-type TiO2 property. For the sample annealed at 700°C, the negative photocurrent is main, which mainly performs the p-type property of TiO2. The IPCE values indicate that the absorption edges are red shifted with the increase of annealing temperatures

Enhanced photocatalysis by coupling of anatase TiO2 film to triangular Ag nanoparticle island

In order to overcome the low utilization ratio of solar light and high electron-hole pair recombination rate of TiO(2), the triangular Ag nanoparticle island is covered on the surface of the TiO(2) thin film. Enhancement of the photocatalytic activity of the Ag/TiO(2) nanocomposite system is observed. The increase of electron-hole pair generation is caused by the enhanced near-field amplitudes of localized surface plasmon of the Ag nanoparticles. The efficiently suppressed recombination of electron-hole pair caused by the metal-semiconductor contact can also enhance the photocatalytic activity of the TiO(2) film

Reconversión laboral del sector agropecuario hacia el turismo. Desafíos para la Patagonia chilena

[EN] The development of tourism can help to diversify the productive matrix and reduce rural depopulation. This study analyzes the possibility of agricultural worker participation in the tourism sector in rural areas of Chilean Patagonia. Based on the 2017 CASEN survey, data matching and estimation of logit model are conducted to evaluate the probability of agricultural worker reconversion. The results indicate that the proportion of agricultural workers who can move to tourism is low. However, women and individuals with post-secondary education are more likely to be reconverted.[ES] La actividad turística puede ayudar a diversificar la matriz productiva y reducir el despoblamiento rural. Este estudio analiza la posibilidad de participación de trabajadores agropecuarios en el sector turismo en las zonas rurales de la Patagonia Chilena. Usando la encuesta CASEN del año 2017, se realiza un proceso de emparejamiento de datos (matching) y la estimación de un modelo logit para evaluar la probabilidad de reconversión laboral. Los resultados indican que hay una baja proporción de trabajadores que puedan transitar hacia el sector turismo. Sin embargo, las mujeres y los individuos con estudios postsecundarios tienen mayores probabilidades de reconversión.Este trabajo está enmarcado dentro del proyecto de investigación “La Vocación Productiva, el Nivel Educativo y la Funcionalidad del Centro Emisor y Receptor como Factores Explicativos de la Conmutación Inter e Intrarregional en la Región de los Andes Australes de la Patagonia Chilena”, financiado por CONICYT (Proyecto Fondecyt Número 1160196), por lo que los autores agradecen dichos aportes.Mancilla, C.; Ferrada, LM.; Soza-Amigo, S. (2019). Labour reconversion of the agricultural sector towards tourism. Challenges for Chilean Patagonia. Economía Agraria y Recursos Naturales - Agricultural and Resource Economics. 19(1):175-194. https://doi.org/10.7201/earn.2019.01.0917519419

One-Pot Reaction and Subsequent Annealing to Synthesis Hollow Spherical Magnetite and Maghemite Nanocages

Abstract Water-soluble hollow spherical magnetite (Fe3O4) nanocages (ca.100 nm) with high saturation magnetization are prepared in a one-pot reaction by sol-gel method and subsequent annealing to synthesise the maghemite (&#947;-Fe2O3) nanocages with similar nanostructures. The nanocages have been investigated by powder X-ray diffraction (XRD), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), and superconducting quantum interference device (SQUID). The results indicated that glutamic acid played an important role in the formation of the cage-like nanostructures.</p

Recent progress in perovskite-based photodetectors: the design of materials and structures

In recent years, taking advantages of high light absorption coefficients, long charge carrier diffusion lengths and intense photoluminescence, halide perovskites have attracted a great deal of interest in developing high-performance optoelectronic devices including solar cells, light-emitting diodes, photodetectors, transistors, lasers, and so on. Especially, the excellent combination of effective light absorption with tailorable absorption spectrum and high charge carrier mobility in a broadband range makes perovskite-based photodetectors different from traditional photodetectors made of inorganic semiconductors such as GaN, Si, and InGaAs. According to the recent reports, perovskites are promising to greatly improve responsivity, detectivity, noise equivalent power, linear dynamic range, and response speed of photodetectors. Here, we summarize the recent advancements in organic–inorganic hybrid perovskite-based photodetectors in terms of the progress in various low-dimension perovskites, and the recent effective approaches to enhance the performance of perovskite photodetector based on the interfacial engineering in perovskite heterostructures. Besides, two kinds of perovskite photodetectors, namely vertical structure and lateral structure, are analyzed, and the challenges to achieve practical applications in photodetectors are also discussed

Catalytic Application and Mechanism Studies of Argentic Chloride Coupled Ag/Au Hollow Heterostructures: Considering the Interface Between Ag/Au Bimetals

Abstract For an economical use of solar energy, photocatalysts that are sufficiently efficient, stable, and capable of harvesting light are required. Composite heterostructures composed of noble metals and semiconductors exhibited the excellent in catalytic application. Here, 1D Ag/Au/AgCl hollow heterostructures are synthesized by galvanic replacement reaction (GRR) from Ag nanowires (NWs). The catalytic properties of these as-obtained Ag/Au/AgCl hollow heterostructures with different ratios are investigated by reducing 4-nitrophenol (Nip) into 4-aminophenol (Amp) in the presence of NaBH4, and the influence of AgCl semiconductor to the catalytic performances of Ag/Au bimetals is also investigated. These hollow heterostructures show the higher catalytic properties than pure Ag NWs, and the AgCl not only act as supporting materials, but the excess AgCl is also the obstacle for contact of Ag/Au bimetals with reactive species. Moreover, the photocatalytic performances of these hollow heterostructures are carried out by degradation of acid orange 7 (AO7) under UV and visible light. These Ag/Au/AgCl hollow heterostructures present the higher photocatalytic activities than pure Ag NWs and commercial TiO2 (P25), and the Ag/Au bimetals enhance the photocatalytic activity of AgCl semiconductor via the localized surface plasmon resonance (LSPR) and plasmon resonance energy transfer (PRET) mechanisms. The as-synthesized 1D Ag/Au/AgCl hollow heterostructures with multifunction could apply in practical environmental remedy by catalytic manners. Graphical abstrac