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Made available in DSpace on 2018-11-29T01:20:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) FINEP Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) In this study, the structure and photoelectrochemical properties of CuWO4 porous films synthesized by a co-precipitation method followed by a hydrothermal treatment were investigated. The film was deposited on fluorine-doped tin oxide (FTO)-conducting glass, from a suspension containing polyethylene glycol, and heat-treated at 500 degrees C for 30 min. X-ray diffraction patterns, the Rietveld refinement data, and the micro-Raman spectrum showed that the CuWO4 film has a triclinic structure. The optical band gap energy of the film was estimated to be 2.45 eV by the Tauc plot. Field emission scanning electron microcopy images of the films indicated that they are about 4.0 +/- 0.5 mm thick. The photoelectrochemical properties of the film were investigated in a Na2SO4 aqueous solution, in the absence of light and under polychromatic irradiation. The CuWO4 film exhibited photoelectrochemical behavior of a n-type semiconductor, with a negative photopotential and an anodic photocurrent density of 68 mu mA cm(-2) at 0.73 V vs. Ag/AgCl (1.23 V vs. RHE). The n-type photoelectrochemical behavior was confirmed by a chronoamperometry measurement biased condition at + 0.7 V, at different pH values. From these studies, it was noted that when the pH values increased from 3 to 11, the photocurrent density increased about 9 times. Also, the flat band potential (E-fb) of the semiconductor was estimated by the Butler-Gartner model at + 0.34 V, which was utilized to calculate the conduction band edge. The studies presented here reveal that the CuWO4 porous film is a promising candidate to be applied as a photoanode in photocatalytic processes under irradiation by visible light. (C) 2017 Elsevier Ltd. All rights reserved. Univ Fed Piaui UFPI, DQ, BR-64049550 Teresina, PI, Brazil Univ Estadual Piaui, DQ, GERATEC, PPGQ, Rua Joao Cabral,2231,POB 381, BR-64002150 Teresina, PI, Brazil Univ Estadual Paulista, CDMF, POB 355, BR-14801907 Araraquara, SP, Brazil Univ Estadual Paulista, CDMF, POB 355, BR-14801907 Araraquara, SP, Brazil CNPq: 455864/2014-4 CNPq: 307559/2015-7 FINEP: 0315/08

Made available in DSpace on 2019-10-04T12:33:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-12-03. Added 1 bitstream(s) on 2019-10-09T18:33:48Z : No. of bitstreams: 1 S0104-64972018000100222.pdf: 2176102 bytes, checksum: 7d0bea2e2bcd6039bf8379c663354084 (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) We determined the infestation rate of Probopyrus sp. in populations of Palaemon pandaliformis (Stimpson, 1871) and P. northropi (Rankin, 1898) in the Ubatumirim River, localized in a mangrove ecosystem on Ubatumirim Beach, northern coast of the state of Sao Paulo, Brazil. Samplings were carried out monthly from April 2003 to March 2004. Monthly prevalence varied from 0 to 4.94 % for P. pandahformis, and from 0 to 4.54 % for P. northropi. This is the first record of Probopyrus sp. infesting the studied species in this region. Species of Probopyrus (Giard and Bonnier, 1888) seem to have a high plasticity with regard to palaemonid hosts, as they can be parasites of shrimps in both Palaemon (Fabricius, 1798) and Macrobrachium (Spence Bate, 1868). The linear relationships between the parasite and host sizes suggest that the parasite infests both hosts early in their development. We concluded that the infestation of Probopyrus sp. has little impact on Palaemon populations, mostly due to the low prevalence of infestation. Univ Fed Piaui UFPI, Dept Biol, Ctr Ciencias Nat, Campus Minist Petronio Portella, Teresina, Piaui, Brazil Univ Estadual Paulista, UNESP, Grp Estudos Biol Ecol & Cult Crustaceos NEBECC, Dept Zool,Inst Biociencias, Botucatu, SP, Brazil Univ Paulista UNIP, Curso Ciencias Biol, Bauru, SP, Brazil Univ Sao Paulo, Dept Zool, Inst Biociencias, Sao Paulo, SP, Brazil Univ Estadual Paulista, UNESP, Grp Estudos Biol Ecol & Cult Crustaceos NEBECC, Dept Zool,Inst Biociencias, Botucatu, SP, Brazil FAPESP: 98/3234-6

Made available in DSpace on 2018-11-27T21:47:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-12-15 LIMAV-UFPI IFPI UERN Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) In this paper, a new synthesis method was proposed to obtain anatase titanium oxide (TiO2) nanocrystals anchored into SBA-15 molecular sieve, as a matrix assigned by the in-situ anchoring (ISA) method. Pure SBA-15 and modified with TiO2 nanocrystals at different Si/Ti molar ratios (R = 75, 50, and 25) were structurally characterized by X-ray diffraction (XRD), Micro-Raman and Fourier Transform infrared (FTIR) spectroscopies. Specific surface area, pore volume and average pore diameter were estimated using both Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods, respectively. Morphological aspects of these samples were observed by means of field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Optical properties were investigated by ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. XRD patterns, Micro-Raman and FT-IR spectra indicate the TiO2 nanocrystals crystallized in a tetragonal structure anchored into the SBA-15 mesopores. BET and BJH methods prove a large amount of TiO2 nanocrystals were anchored inside of SBA-15 mesopores due to increase in surface area and average pore size of SBA-15 matrix. FE-SEM and TEM images showed the pure SBA-15 has an elongated hexagon-shaped microstructure, and an average size of 7.34 nm for 2D hexagonal mesopores. Moreover, ISA method was able to avoid blocking of mesopores, in addition promotes a significant increasing the impregnation rate of anatase TiO2 nanocrystals in SBA-15 matrix. A growth mechanism was proposed in order to explain the stages involved in the formation of TiO2-SBA mesoporous. UV-vis spectra revealed a dependence of the optical band gap energy (E-gap) with the decreasing of Si/Ti molar ratios. (C) 2016 Elsevier B.V. All rights reserved. Univ Estadual Piaui, PPGQ GERATEC CCN DQ, Joao Cabral,2231,POB 381, BR-64002150 Teresina, PI, Brazil Univ Fed Piaui UFPI, DQ, BR-64049550 Teresina, PI, Brazil CDMF Univ Estadual Paulista, POB 355, BR-14801907 Araraquara, SP, Brazil Univ Estado Rio Grande do Norte, Dept Ciencias Nat, Mossoro, RN, Brazil CDMF Univ Estadual Paulista, POB 355, BR-14801907 Araraquara, SP, Brazil CNPq: 307559/2015-7 CNPq: 350711/2012-7 CNPq: 479644/2012-8 CNPq: 455864/2014-4 FAPESP: 12/14004-5 FAPESP: 13/07296-2 CAPES: 33001014005P5 CAPES: 20131475