Semiconductors are key materials in modern electronics and are widely used to build, for instance, transistors in integrated circuits as well as thermoelectric materials for energy conversion, and there is a tremendous interest in the development and improvement of novel materials and technologies to increase the performance of electronic devices and thermoelectrics. Tetramorphic Ag(10)Te(4)Br(3) is a semiconductor capable of switching its electrical properties by a simple change of temperature. The combination of high silver mobility, a small non-stoichiometry range and an internal redox process in the tellurium substructure causes a thermopower drop of 1,400 microV K(-1), in addition to a thermal diffusivity in the range of organic polymers. The capability to reversibly switch semiconducting properties from ionic to electronic conduction in one single compound simply by virtue of temperature enables novel electronic devices such as semiconductor switches.
251 83 367 05 Doped ceria and ceria based solid oxide solutions show a unique combination of oxygen ion mobility, electronic conductivity, and high catalytic activity for redox reactions. In this work, the minority conductivity of electrons has been measured directly as a function of the composition of ceria-praseodymia based solid solutions in order to maximize the electronic conductivity without depressing the oxygen ion mobility. The influence of Co as well as the Gd/Pr dopant ratio on the electronic conductivity of ceria-praseodymia pellets was studied for the compositions Ce 0.8 Gd 0.2Àx Pr x O 2Àd (0.05 x 0.15) with and without an additional Co content of 0.02 with respect to the formula. The Hebb-Wagner polarization technique was used with ion-blocking microcontacts. In the temperature range 700-800 8C, the presence of high amounts of praseodymium increases the p-type conductivity by a factor of more than 10 for oxygen partial pressures higher than 10 À10 bar. Co-doped ceria-gadolinia-praseodymia solid solutions showed a further increase of the electronic conductivities in a partial pressure range where the Co-free materials showed the minimum of the electronic conductivities. It is assumed that the effect of the additional cobalt doping is due to electronic short circuits along the grain boundaries via segregated CoO.
The gas-phase ammoxidation of ethanol, a bio-based platform molecule, has been investigated as a possible more sustainable route for the production of acetonitrile, using supported vanadium oxide catalysts. The nature of the interaction between the support and the active species greatly affected the catalytic performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.