Carbon-supported trimetallic catalysts (PdAuNi/C) for borohydride oxidation reaction

The synthesis of palladium-based trimetallic catalysts via a facile and scalable synthesis procedure was shown to yield highly promising materials for borohydride-based fuel cells, which are attractive for use in compact environments. This, thereby, provides a route to more environmentally friendly energy storage and generation systems. Carbon-supported trimetallic catalysts were herein prepared by three different routes: using a NaBH4-ethylene glycol complex (PdAuNi/CSBEG), a NaBH4-2-propanol complex (PdAuNi/CSBIPA), and a three-step route (PdAuNi/C3-step). Notably, PdAuNi/CSBIPA yielded highly dispersed trimetallic alloy particles, as determined by XRD, EDX, ICP-OES, XPS, and TEM. The activity of the catalysts for borohydride oxidation reaction was assessed by cyclic voltammetry and RDE-based procedures, with results referenced to a Pd/C catalyst. A number of exchanged electrons close to eight was obtained for PdAuNi/C3-step and PdAuNi/CSBIPA (7.4 and 7.1, respectively), while the others, PdAuNi/CSBEG and Pd/CSBIPA, presented lower values, 2.8 and 1.2, respectively. A direct borohydride-peroxide fuel cell employing PdAuNi/CSBIPA catalyst in the anode attained a power density of 47.5 mW cm−2 at room temperature, while the elevation of temperature to 75 °C led to an approximately four-fold increase in power density to 175 mW cm−2. Trimetallic catalysts prepared via this synthesis route have significant potential for future development

Nanometric Particle Size And Phase Controlled Synthesis And Characterization Of γ-fe2o3 Or (α + γ)-fe2o3 By A Modified Sol-gel Method

Fe2O3 nanoparticles with sizes ranging from 15 to 53 nm were synthesized by a modified sol-gel method. Maghemite particles as well as particles with admixture of maghemite and hematite were obtained and characterized by XRD, FTIR, UV-Vis photoacoustic and Mössbauer spectroscopy, TEM, and magnetic measurements. The size and hematite/maghemite ratio of the nanoparticles were controlled by changing the Fe:PVA (poly (vinyl alcohol)) monomeric unit ratio used in the medium reaction (1:6, 1:12, 1:18, and 1:24). The average size of the nanoparticles decreases, and the maghemite content increases with increasing PVA amount until 1:18 ratio. The maghemite and hematite nanoparticles showed cubic and hexagonal morphology, respectively. Direct band gap energy were 1.77 and 1.91 eV for A6 and A18 samples. Zero-field-cooling-field-cooling curves show that samples present superparamagnetic behavior. Maghemite-hematite phase transition and hematite Néel transition were observed near 700 K and 1015 K, respectively. Magnetization of the particles increases consistently with the increase in the amount of PVA used in the synthesis. Mössbauer spectra were adjusted with a hematite sextet and maghemite distribution for A6, A12, and A24 and with maghemite distribution for A18, in agreement with XRD results. © 2013 AIP Publishing LLC.11410Xu, P., Zeng, G.M., Huang, D.L., Feng, C.L., Hu, S., Zhao, M.H., Lai, C., Liu, Z.F., (2012) Sci. Total Environ., 424, pp. 1-10. , 10.1016/j.scitotenv.2012.02.023Rajabi, F., Karimi, N., Saidi, M.R., Primo, A., Varma, R.S., Luque, R., (2012) Adv. Synth. Catal., 354, pp. 1707-1711. , 10.1002/adsc.201100630Kitamuraa, H., Zhaob, L., Hangc, B.T., Okadab, S., Yamaki, J.-I., (2012) J. Power Sources, 208, pp. 391-396. , 10.1016/j.jpowsour.2012.02.051Figuerola, A., Di Corato, R., Manna, L., Pellegrino, T., (2010) Pharmacol. Res., 62, pp. 126-143. , 10.1016/j.phrs.2009.12.012Yang, H.-M., Oh, B.C., Kim, J.H., Ahn, T., Nam, H.-S., Park, C.W., Kim, J.-D., (2011) Colloids Surf., A, 391, pp. 208-215. , 10.1016/j.colsurfa.2011.04.032Xu, H., Aguilar, Z.P., Yang, L., Kuang, M., Duan, H., Xiong, Y., Wei, H., Wang, A., (2011) Biomaterials, 32, pp. 9758-9765. , 10.1016/j.biomaterials.2011.08.076Mahmoudi, M., Sant, S., Wang, B., Laurent, S., Sen, T., (2011) Adv. Drug Delivery Rev., 63, pp. 24-46. , 10.1016/j.addr.2010.05.006Jolivet, J.-P., Cassaignon, S., Chanéac, C., Chiche, D., Durupthy, O., Portehault, D., (2010) C. R. Chim., 13, pp. 40-51. , 10.1016/j.crci.2009.09.012Yang, S., Jang, Y.-H., Kim, C.H., Hwang, C., Lee, J., Chae, S., Jung, S., Choi, M., (2010) Powder Technol., 197, pp. 170-176. , 10.1016/j.powtec.2009.09.011Wu, Y., Wang, X., (2011) Mater. Lett., 65, pp. 2062-2065. , 10.1016/j.matlet.2011.04.004Fernandes, D.M., Hechenleitner, A.A.W., Silva, M.F., Lima, M.K., Bittencourt, P.R.S., Silva, R., Melo, M.A.C., Pineda, E.A.G., (2009) Mater. Chem. Phys., 118, pp. 447-452. , 10.1016/j.matchemphys.2009.08.016Han, L.-H., Liu, H., Wei, Y., (2011) Powder Technol., 207, pp. 42-46. , 10.1016/j.powtec.2010.10.008Chen, L., Lin, Z., Zhao, C., Zheng, Y., Zhou, Y., Peng, H., (2011) J. Alloy Compd., 509, pp. 1-L5. , 10.1016/j.jallcom.2010.08.130Hassanjani-Roshan, A., Vaezi, M.R., Shokuhfar, A., Rajabali, Z., (2011) Particuology, 9, pp. 95-99. , 10.1016/j.partic.2010.05.013Khaleel, A., Al-Marzouqi, A., (2012) Mater. Lett., 68, pp. 385-387. , 10.1016/j.matlet.2011.11.002Komarneni, S., Hu, W., Noh, Y.D., Orden, A.V., Feng, S., Wei, C., Pang, H., Katsuki, H., (2012) Ceram. Int., 38, pp. 2563-2568. , 10.1016/j.ceramint.2011.11.027Fernandes, D.M., Silva, R., Hechenleitner, A.A.W., Radovanovic, E., Melo, M.A.C., Pineda, E.A.G., (2009) Mater. Chem. Phys., 115, pp. 110-115. , 10.1016/j.matchemphys.2008.11.038Rodriguez-Carvajal, J., (1993) Physica B, 192, pp. 55-69. , 10.1016/0921-4526(93)90108-ICornell, R.M., Sshwertmann, U., (2003) The Iron Oxides: Structures, Properties, Reactions, Occurrences and Uses, , (John Wiley Sons)Gotic, M., Music, S., Mössbauer, FT-IR and FE SEM investigation of iron oxides precipitated from FeSO4 solutions (2007) Journal of Molecular Structure, 834-836 (SPEC. ISS.), pp. 445-453. , DOI 10.1016/j.molstruc.2006.10.059, PII S0022286006009513Predoi, D., (2007) Dig. J. Nanomater. Biostruct., 2, pp. 169-173Namduri, H., Nasrazadani, S., (2008) Corros. Sci., 50, pp. 2493-2497. , 10.1016/j.corsci.2008.06.034Gulgun, M.A., Nguyen, M.H., Kriven, W.M., (1999) J. Am. Ceram. Soc., 82, pp. 556-560. , 10.1111/j.1151-2916.1999.tb01800.xFeng, J., Liu, T., Xu, Y., Zhao, J., He, Y., (2011) Ceram. Int., 37, pp. 1203-1207. , 10.1016/j.ceramint.2010.11.045Park, T.-J., Papaefthymiou, G.C., Moodenbaugh, A.R., Mao, Y., Wong, S.S., Synthesis and characterization of submicron single-crystalline Bi 2Fe4O9 cubes (2005) Journal of Materials Chemistry, 15 (21), pp. 2099-2105. , DOI 10.1039/b501552aLiu, T., Xu, Y., Zhao, J., (2010) J. Am. Ceram. Soc., 93, pp. 3637-3641. , 10.1111/j.1551-2916.2010.03945.xSarangi, P.P., Naik, B., Ghosh, N.N., (2009) Powder Technol., 192, pp. 245-249. , 10.1016/j.powtec.2009.01.002Sarangi, P.P., Naik, B.D., Vadera, S.R., Patra, M.K., Prakash, C., Ghosh, N.N., (2009) Mater. Technol.: Adv. Perform. Mater., 24, pp. 97-99. , 10.1179/175355509X387156Tauc, J., Grigorovici, R., Vancu, A., (1966) Phys. Status Solidi, 15, p. 627. , 10.1002/pssb.19660150224Martinez, F.L., Toledano-Luque, M., Gandia, J.J., Carabe, J., Bohne, W., Rohrich, J., Strub, E., Martil, I., Optical properties and structure of HfO2 thin films grown by high pressure reactive sputtering (2007) Journal of Physics D: Applied Physics, 40 (17), pp. 5256-5265. , DOI 10.1088/0022-3727/40/17/037, PII S0022372707493032, 037Rahman, M.M., Khan, S.B., Faisal, M., Asiri, A.M., Tariq, M.A., (2012) Electrochim. Acta, 75, pp. 164-170. , 10.1016/j.electacta.2012.04.093Gilbert, B., Frandsen, C., Maxey, E.R., Sherman, D.M., (2009) Phys. Rev. B, 79, p. 035108. , 10.1103/PhysRevB.79.035108Echigo, T., Aruguete, D.M., Murayamac, M., Hochella Jr., M.F., (2012) Geochim. Cosmochim. Acta, 90, pp. 149-162. , 10.1016/j.gca.2012.05.008Duret, A., Gratzel, M., Visible light-induced water oxidation on mesoscopic α-Fe 2O3 films made by ultrasonic spray pyrolysis (2005) Journal of Physical Chemistry B, 109 (36), pp. 17184-17191. , DOI 10.1021/jp044127cSouza, F.L., Lopes, K.P., Nascente, P.A.P., Leite, E.R., (2009) Sol. Energy Mater. Sol. Cells, 93, pp. 362-368. , 10.1016/j.solmat.2008.11.049De Oliveira, L.A.S., Sinnecker, J.P., Vieira, M.D., Penton-Madrigal, A., (2010) J. Appl. Phys., 107, pp. 09D907. , 10.1063/1.3362927Ennas, G., Marongiu, G., Musinu, A., Falqui, A., Ballirano, P., Caminiti, R., (1999) J. Mater. Res., 14, pp. 1570-1575. , 10.1557/JMR.1999.0210Wu, J., Mao, S., Ye, Z., Xie, Z., Zheng, L., (2010) ACS Appl. Mater. Interfaces, 2, pp. 1561-1564. , 10.1021/am1002052Phu, N.D., Ngo, D.T., Hoang, L.H., Luong, N.H., Chau, N., Hai, N.H., (2011) J. Phys. D: Appl. Phys., 44, p. 345002. , 10.1088/0022-3727/44/34/345002Nagar, H., Kulkarni, N.V., Karmakar, S., Sahoo, B., Banerjee, I., Chaudhari, P.S., Pasricha, R., Keune, W., (2008) Mater. Charact., 59, pp. 1215-1220. , 10.1016/j.matchar.2007.10.003Goulart, A.T., Filho D. F M, J., (1994) Hyperfine Interact., 83, pp. 451-455. , 10.1007/BF02074316Costa, G.M., Grave, E., Bowen, L.H., Vandenberghe, R.E., Bakker, P.M.A., (1994) Clay Clay Miner., 42, pp. 628-633. , 10.1346/CCMN.1994.042051

Optimization of maghemite-loaded PLGA nanospheres for biomedical applications

Magnetic nanoparticles have been proposed as interesting tools for biomedical purposes. One of their promising utilization is the MRI in which magnetic substances like maghemite are used in a nanometric size and encapsulated within locally biodegradable nanoparticles. In this work, maghemite has been obtained by a modified sol-gel method and encapsulated in polymer-based nanospheres. The nanospheres have been prepared by single emulsion evaporation method. The different parameters influencing the size, polydispersity index and zeta potential surface of nanospheres were investigated. The size of nanospheres was found to increase as the concentration of PLGA increases, but lower sizes were obtained for 3 min of sonication time and surfactant concentration of 1%. Zeta potential response of magnetic nanospheres towards pH variation was similar to that of maghemite-free nanospheres confirming the encapsulation of maghemite within PLGA nanospheres. The maghemite entrapment efficiency and maghemite content for nanospheres are 12% and 0.59% w/w respectively

Trimetallic carbon-supported catalysts for borohydride oxidation and oxygen reduction in alkaline solutions

ECEE 2019 meeting abstract

Survey of mutations in prolificacy genes in Santa Ines and Morada Nova sheep

ABSTRACT Polymorphisms in the BMP-15 gene related to Galway (FecXG) and Inverdale (FecXI) and in the BMPR-1B gene known as Booroola (FecB) mutations were investigated using the Polymerase Chain Reaction - Restriction Fragment Length Polymorphism (PCR-RFLP) method, on sheep from the breeds Santa Inês (n= 574) and Morada Nova (n=282). DNA was extracted and amplified through PCR with specific primers that introduced a restriction site in association with the mutation. The PCR products were submitted to endonucleases. The experiment found no FecXG and FecXI mutations. Six samples of animals with multiple offspring/birth history presented polymorphism for FecB similar to control samples, but this pattern was not confirmed by nucleotide sequencing. Although the absence of these mutations in the studied breeds, other factors related to prolificacy should be investigated to explain the inherent prolificity mechanisms

Expressão gênica de adipocinas em ovelhas alimentadas com resíduos da indústria do biodiesel da mamona

A expressão de RNAm para leptina, receptor de leptina (obRb), adiponectina, receptor de adiponectina (AdipoR1) e resistina foi avaliada por meio da técnica de PCR em tempo real, em tecidos ovariano, hipofisário, adiposo do omento e da região perirrenal, em ovelhas alimentadas sem farelo de mamona ou com farelo de mamona detoxificada durante 14 meses. O tipo de dieta não afetou os níveis de RNAm para leptina, obRb, adiponectina, AdipoR1 e resistina nos diferentes tecidos avaliados (P>0,05). Nos tecidos ovariano e hipofisário, não foi verificada a expressão da adiponecina e da resistina, respectivamente. Como consequência, pode-se concluir que o farelo de mamona detoxificada pode ser utilizado como fonte proteica na dieta de ovelhas, sem afetar a expressão do gene resistina e dos genes leptina e adiponectina, bem como de seus receptores

Optimization of maghemite-loaded PLGA nanospheres for biomedical applications

Magnetic nanoparticles have been proposed as interesting tools for biomedical purposes. One of their promising utilization is the MRI in which magnetic substances like maghemite are used in a nanometric size and encapsulated within locally biodegradable nanoparticles. In this work, maghemite has been obtained by a modified sol-gel method and encapsulated in polymer-based nanospheres. The nanospheres have been prepared by single emulsion evaporation method. The different parameters influencing the size, polydispersity index and zeta potential surface of nanospheres were investigated. The size of nanospheres was found to increase as the concentration of PLGA increases, but lower sizes were obtained for 3 min of sonication time and surfactant concentration of 1%. Zeta potential response of magnetic nanospheres towards pH variation was similar to that of maghemite-free nanospheres confirming the encapsulation of maghemite within PLGA nanospheres. The maghemite entrapment efficiency and maghemite content for nanospheres are 12% and 0.59% w/w respectively