22 documents found, page 1 of 3
High-performance thermoelectric oxides: processing approaches and composition d...
Kovalevsky, Andrei; Constantinescu, Gabriel; Lopes, Diogo; Zakharchuk, Kiryl V.; Rasekh, Shahed; Yaremchenko, Aleksey A.; Ferreira, Nuno M.; Xie, WenjieOxide materials represent a promising alternative to traditional thermoelectrics, by providing a possibility to operate at high temperatures, resulting in a higher Carnot efficiency. Although their conversion efficiency is considerably lower, their known structural and microstructural versatility can open new horizons for thermoelectric applications. This work reviews some representative cases of engineering th...
Exploring the strategies towards enhancing the thermoelectric performance in ox...
Kovalevsky, Andrei; Constantinescu, Gabriel; Lopes, Diogo; Ferreira, Nuno M.; Zakharchuk, Kiryl; Paulino, Tiago; Zúquete, Joana; Suarez, DianaOxide materials are currently considered a promising alternative to traditional thermoelectrics. Moderate charge carrier mobility stemming from strong covalent and ionic bonding, combined with relatively high thermal conductivity, represent known disadvantages of these materials for thermoelectric applications. However, oxides offer a possibility to operate at high temperatures, resulting in a higher Carnot eff...
Enhancement of thermoelectric performance of donor-doped ZnO ceramics by involv...
Constantinescu, Gabriel; Galatanu, Andrei; Tobaldi, David; Mikhalev, Sergey; Suarez, Diana; Paulino, Tiago; Zakharchuk, Kiryl; Sergiienko, SergiiThis work explores the possibility of involving aluminothermy in processing donor-doped zinc oxide-based thermoelectrics by relying on local, strong exothermic effects developed during sintering, with a potential positive impact on the electrical and thermal transport properties. The strategy was exemplified by using aluminium as a dopant, due to its recognized ability to generate additional, available charge c...
Exploring the high-temperature thermoelectric performance of la-substituted Ca3...
Constantinescu, Gabriel; Lopes, Daniela V.; Amir Khizi, Parisa; Vieira, Miguel A.; Kavaleuski, AndreiIt is well-known that the electrical properties of the Ca3Co4O9 thermoelectric (TE) compound are strongly influenced by the valence of the substituting cation, while its solubility and “functional” impact depend largely on the preparation and/or processing methods used. Furthermore, this material’s hybrid crystal structure allows for different cation substitutions in/from different sublattices. This research wo...
Photocatalytic removal of benzene over Ti3C2Tx MXene and TiO2–MXene composite m...
Sergiienko, S.A.; Tobaldi, David M.; Lajaunie, Luc; Lopes, Daniela V.; Constantinescu, Gabriel; Shaula, A.L.; Shcherban, Nataliya D.MXenes, a family of two-dimensional (2D) transition metal carbides, nitrides and carbonitrides based on earth-abundant constituents, are prospective candidates for energy conversion applications, including photocatalysis. While the activity of individual MXenes towards various photocatalytic processes is still debatable, these materials were proved to be excellent co-catalysts, accelerating the charge separatio...
Redox-promoted tailoring of the high-temperature electrical performance in Ca3C...
Constantinescu, Gabriel; Sarabando, Artur R.; Rasekh, Shahed; Lopes, Diogo; Sergiienko, Sergii; Amirkhizi, Parisa; Frade, Jorge R.This paper reports a novel composite-based processing route for improving the electrical performance of Ca3Co4O9 thermoelectric (TE) ceramics. The approach involves the addition of metallic Co, acting as a pore filler on oxidation, and considers two simple sintering schemes. The (1-x)Ca3Co4O9/xCo composites (x = 0%, 3%, 6% and 9% vol.) have been prepared through a modified Pechini method, followed by one- and t...
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...
Exploring the high-temperature electrical performance of Ca3-xLaxCo4O9 thermoel...
Constantinescu, Gabriel; Rasekh, Shahed; Amirkhizi, Parisa; Lopes, Daniela V.; Vieira, Miguel A.; Kovalevsky, Andrei V.; Diez, Juan C.; Sotelo, AndresAliovalent substitutions in Ca3Co4O9 often result in complex effects on the electrical prop-erties and the solubility, and impact of the substituting cation also depends largely on the prepara-tion and processing method. It is also well-known that the monoclinic symmetry of this material’s composite crystal structure allows for a significant hole transfer from the rock salt-type Ca2CoO3 buffer layers to the hex...
Exploring the high-temperature thermoelectric performance of Al-doped ZnO ceram...
Constantinescu, Gabriel; Mikhalev, Sergey M.; Zakharchuk, Kiryl V.; Kovalevsky, Andrei V.Zinc oxide (ZnO) is a highly versatile and well-known material, widely used for its useful optoelectronic, catalytic, and photochemical properties [1]. In the search for alternative energy sources, ZnO-based ceramics emerge as promising materials for high-temperature thermoelectric (TE) applications [2], capable of direct conversion of (waste) heat to electricity, thanks to the Seebeck effect. Owing to the spec...
Microstructural aspects affecting the performance of thermoelectric oxides: sel...
Kovalevsky, Andrei V.; Arias-Serrano, Blanca I.; Constantinescu, Gabriel; Zakharchuk, Kiryl; Rasekh, Shahed; Ferreira, Nuno M.; Xie, WenjieOxide materials represent certain advantages as compared to traditional thermoelectric materials, including stability at high temperatures and versatility regarding the gas atmosphere composition. Microstructural aspects play a crucial role in the performance of oxides, often dominating even over chemical composition effects. Thus, engineering the microstructure in these materials represents a powerful tool tow...