13 documents found, page 1 of 2
Prospects for electrical performance tuning in Ca3Co4O9 materials by metallic F...
Constantinescu, Gabriel; Mikhalev, Sergey M.; Lisenkov, Aleksey D.; Lopes, Daniela V.; Sarabando, Artur R.; Ferro, Marta C.; Silva, Tiago F. daThis work further explores the possibilities for designing the high-temperature electrical performance of the thermoelectric Ca3Co4O9 phase, by a composite approach involving separate metallic iron and nickel particles additions, and by employing two different sintering schemes, capable to promote the controlled interactions between the components, encouraged by our recent promising results obtained for similar...
On the high-temperature degradation mechanism of ZnO-based thermoelectrics
Arias-Serrano, Blanca I.; Mikhalev, Sergey M.; Ferro, Marta C.; Tobaldi, David M.; Frade, Jorge R.; Kovalevsky, Andrei V.The stability and reproducibility of the electric properties in n-type doped ZnO represent known bottlenecks towards potential thermoelectric applications. The degradation is promoted by the vanishing of the electronic defects on oxidation and irreversible exsolution of the phase impurities. This work proposes a microstructural mechanism showing that these processes take place mainly in the pores and highlighti...
Prospects for electrical performance tuning in Ca3Co4O9 materials by metallic F...
Constantinescu, Gabriel; Mikhalev, Sergey M.; Lisenkov, Aleksey D.; Lopes, Daniela V.; Sarabando, Artur R.; Ferro, Marta C.; Silva, Tiago F. daThis work further explores the possibilities for designing the high-temperature electrical performance of the thermoelectric Ca3Co4O9 phase, by a composite approach involving separate metallic iron and nickel particles additions, and by employing two different sintering schemes, capable to promote the controlled interactions between the components, encouraged by our recent promising results obtained for similar...
MXene-containing composite electrodes for hydrogen evolution: material design a...
Sergiienko, Sergii A.; Lopes, Daniela V.; Constantinescu, Gabriel; Ferro, Marta C.; Shchaerban, Nataliya D.; Tursunov, Obid B.; Shkepu, Viacheslav I.This work explores the possibilities for the processing of Ni- and Ti3C2Tx (T = OH, O) MXene-containing composite electrodes, by co-pressing and plastic deformation or by etching of the electrodes prepared directly by self-propagation high-temperature synthesis (SHS). Various material design approaches were also explored. In order to tune the Ti3C2 interlayer distance in Ti3C2Al MAX phase, an introduction of ad...
Novel highly luminescent amine-functionalized bridged silsesquioxanes
Pereira, Rui F. P.; Nunes, Sílvia C.; Toquer, Guillaume; Cardoso, Marita A.; Valente, Artur J. M.; Ferro, Marta C.; Silva, Maria M.; Carlos, Luís D.Amine-functionalized bridged silsesquioxanes (BSs) were synthesized from bis[(3-trimethoxysilyl)propyl] amine via a solvent-mediated route. BS-1 and BS-2 were obtained at neutral pH with sub- and stoichiometric amounts of water, respectively, and high tetrahydrofuran content. BS-3 was prepared with hyperstoichiometric water concentration, high tetrahydrofuran content, and hydrochloric acid. BS-4 was synthesized...
Novel Highly Luminescent Amine-Functionalized Bridged Silsesquioxanes
Pereira, Rui F. P.; Nunes, Sílvia C; Toquer, Guillaume; Cardoso, Marita A; Valente, Artur J. M.; Ferro, Marta C.; Silva, Maria M.; Carlos, Luís D.Amine-functionalized bridged silsesquioxanes (BSs) were synthesized from bis[(3-trimethoxysilyl)propyl] amine via a solvent-mediated route. BS-1 and BS-2 were obtained at neutral pH with sub- and stoichiometric amounts of water, respectively, and high tetrahydrofuran content. BS-3 was prepared with hyperstoichiometric water concentration, high tetrahydrofuran content, and hydrochloric acid. BS-4 was synthesized...
Application of scanning electron microscopy–energy dispersive X-Ray spectroscop...
Girão, Ana Violeta; Caputo, Gianvito; Ferro, Marta C.In scanning electron microscopy (SEM), a highly energetic and focused electron beam scans the sample and normally provides an extremely enlarged image of the morphology of the sample, as well as information on its chemical composition using an energy dispersive spectrometer (EDS) detector. SEM-EDS is mainly used for characterization of materials, but lately its application has been extended to study organic-bas...
A new concept of ceramic consumable anode for iron pyroelectrolysis in magnesiu...
Ferreira, Nuno M.; Kovalevsky, Andrei V.; Ferro, Marta C.; Costa, Florinda M.; Frade, Jorge R.Drivenbyenvironmentalchallengesandglobalmovementtocarbonleantechnologies,thepyroelec trolysisprocessforironextractionfromoxidemeltsisbeingproposedasaninterestingalternativetothe traditional steelmaking.Still,oneofthecriticalissuesimpactingtheprospectsofthistechnologyincludes the developmentofappropriateanodematerials,takingintoaccounttheextremelyaggressivenatureof oxidemeltsatveryhightemperatures.Hereweproposea...
Simultaneous CVD synthesis of graphene-diamond hybrid films
Carvalho, Alexandre F.; Holz, Tiago; Santos, Nuno F.; Ferro, Marta C.; Martins, Manuel A.; Fernandes, Antonio J. S.; Silva, Rui F.; Costa, Florinda M.An innovation is reported in the synthesis of a hybrid carbon structure resulting from the simultaneous growth of graphene and nanocrystalline diamond (NCD) by the microwave plasma chemical vapor deposition technique. This strategy allows to take advantage of the complementary electronic behavior of each carbon allotrope, a key feature in new nanostructured materials for electronics under the graphene/insulator...
A new concept of ceramic consumable anode for iron pyroelectrolysis in magnesiu...
Ferreira, Nuno M.; Kovalevsky, Andrei V.; Ferro, Marta C.; Costa, Florinda M.; Frade, Jorge R.Driven by environmental challenges and global movement to carbon-lean technologies, the pyroelectrolysis process for iron extraction from oxide melts is being proposed as an interesting alternative to the traditional steelmaking. Still, one of the critical issues impacting the prospects of this technology includes the development of appropriate anode materials, taking into account the extremely aggressive natur...