Synthesis, Characterization and Optical Activity of RE-doped ZnWO4 Nanorods and Nanospheres by Hydrothermal Method

This work has investigated the effect of different dopants on structure, morphology and optical property of ZnWO4. Rare-earth doped ZnWO4 (ZnWO4:RE, with 0.5, 1, and 2 mol% of Eu3+ and Pr3+) were successfully synthesized by coprecipitation method followed by microwave-assisted hydrothermal system at 140 °C for 1 h. XRD indicated that the crystals have a wolframite- type monoclinic structure and with the addition of dopants the crystallite size decreased. HR-TEM images revealed interesting homogenous nanorods for pure ZnWO4 crystals with grow along (021) direction. For ZnWO4: RE we have found nanospheres morphologies, in which the decreasing crystal size were dependent on the RE doping concentration. IR spectra confirm the crystals structure. Ultraviolet–Visible diffuse reflectance spectra indicated that the optical band gap varies with increasing replacement of Zn2+ by RE ions. Egap was characteristic of semiconductor materials. DOI: http://dx.doi.org/10.17807/orbital.v11i2.1350 &nbsp

Interface Influence on Photocatalytic Properties of Ag2MoO4/ZnO Heterojunctions

Ag2MoO4/ZnO heterostructures were synthesized by a co-precipitation method in room temperature. XRD studies have showed the formation of the heterostructures containing wurtzite-type structure with hexagonal phase (ZnO) and spinel-type cubic structures (Ag2MoO4). The crystal morphologies and sizes were observed by field emission scanning electron microscopy (FE-SEM). The photocatalytic activities were evaluated by the degradation of rhodamine B (RhB) under ultraviolet light irradiation. DOI: http://dx.doi.org/10.17807/orbital.v11i2.136

Synthesis, Characterization and Optical Activity of RE-doped ZnWO4 Nanorods and Nanospheres by Hydrothermal Method

This work has investigated the effect of different dopants on structure, morphology and optical property of ZnWO4. Rare-earth doped ZnWO4 (ZnWO4:RE, with 0.5, 1, and 2 mol% of Eu3+ and Pr3+) were successfully synthesized by coprecipitation method followed by microwave-assisted hydrothermal system at 140 °C for 1 h. XRD indicated that the crystals have a wolframite- type monoclinic structure and with the addition of dopants the crystallite size decreased. HR-TEM images revealed interesting homogenous nanorods for pure ZnWO4 crystals with grow along (021) direction. For ZnWO4: RE we have found nanospheres morphologies, in which the decreasing crystal size were dependent on the RE doping concentration. IR spectra confirm the crystals structure. Ultraviolet–Visible diffuse reflectance spectra indicated that the optical band gap varies with increasing replacement of Zn2+ by RE ions. Egap was characteristic of semiconductor materials. DOI: http://dx.doi.org/10.17807/orbital.v11i2.1350

The Influence of Magnetic Field and Nanoparticle Concentration on the Thin Film Colloidal Deposition Process of Magnetic Nanoparticles: The Search for High-Efficiency Hematite Photoanodes

Hematite is considered a promising photoanode material for photoelectrochemical water splitting, and the literature has shown that the photoanode production process has an impact on the final efficiency of hydrogen generation. Among the methods used to process hematite photoanode, we can highlight the thin films from the colloidal deposition process of magnetic nanoparticles. This technique leads to the production of high-performance hematite photoanode. However, little is known about the influence of the magnetic field and heat treatment parameters on the final properties of hematite photoanodes. Here, we will evaluate those processing parameters in the morphology and photoelectrochemical properties of nanostructured hematite anodes. The analysis of thickness demonstrated a relationship between the magnetic field and nanoparticles concentration utilized to prepare the thin films, showing that the higher magnetic fields decrease the thickness. The Jabs results corroborate to influence the magnetic field since the use of a higher magnetic field decreases the deposited material amount, consequently decreasing the absorption of the thin films. The PEC measurements showed that at higher concentrations, the use of higher magnetic fields increases the JPH values, and lower magnetic fields cause a decrease in JPH when using the higher nanoparticle concentrations

ESTUDO DA CINÉTICA DE DEGRADAÇÃO DO CORANTE AZUL DE METILENO UTILIZANDO CATALISADORES DE CÉRIA DOPADA COM ÍNDIO

A céria (CeO2) tem atraído a atenção de muitos pesquisadores devido à sua variabilidade de aplicações. Entretanto, este trabalho teve como finalidade investigar a influência do dopante índio (In) na morfologia e nas propriedades fotocatalíticas da céria. A céria dopada com 10, 15 e 20% em mol de índio (Ce1-xInxO2) foi obtida pelo método de coprecipitação acrescida do tratamento hidrotérmico assistido por micro-ondas. Os materiais obtidos apresentaram diferentes morfologias com tamanhos entre 200 e 600 nm, dependendo da concentração de dopante utilizada. A morfologia também tem corroborarado nas propriedades fotocatalíticas observadas na degradação do azul de metileno, em que houve um melhor resultado nas proporções de 10 e 15% em mol de índio. Por intermédio do perfil cinético observou-se que todos os materiais são regidos por uma lei de velocidade de pseudo primeira ordem

Interface Influence on Photocatalytic Properties of Ag2MoO4/ZnO Heterojunctions

Ag2MoO4/ZnO heterostructures were synthesized by a co-precipitation method in room temperature. XRD studies have showed the formation of the heterostructures containing wurtzite-type structure with hexagonal phase (ZnO) and spinel-type cubic structures (Ag2MoO4). The crystal morphologies and sizes were observed by field emission scanning electron microscopy (FE-SEM). The photocatalytic activities were evaluated by the degradation of rhodamine B (RhB) under ultraviolet light irradiation. DOI: http://dx.doi.org/10.17807/orbital.v11i2.1364 </p

NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans—anteaters, sloths, and armadillos—have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data