Unusual semiconductor–metal–semiconductor transitions in magnetite Fe₃O₄ nanoparticles

Abstract

Herein, we report the existence of a novel semiconductor–metal–semiconductor type transition in Fe3O4 nanoparticles by employing impedance spectroscopy techniques.

Fabrication of La3+ doped Ba1−xLaxTiO3 ceramics with improved dielectric and ferroelectric properties using a composite-hydroxide-mediated method

“…The activation energies ( E a ) were calculated from the slopes of the linear regions of plots between ln σ and 1000/ T of all prepared samples in different regions using the Arrhenius law given below:where σ o is the pre-exponential factor, E a is the activation energy, k B is the Boltzmann constant and T is the absolute temperature. 48 Table 2 shows the calculated values of E a ′s for the prepared samples in different regions at a representative frequencies of 1 kHz, 10 kHz and 100 kHz. We found that the BaTiO 3 sample has a large values of E a due to bigger grain size.…”

“…where s o is the pre-exponential factor, E a is the activation energy, k B is the Boltzmann constant and T is the absolute temperature. 48 Table 2 shows the calculated values of E a ′ s for the prepared samples in different regions at a representative frequencies of 1 kHz, 10 kHz and 100 kHz. We found that the BaTiO 3 sample has a large values of E a due to bigger grain size.…”

A Cobalt–Platinum–Ruthenium System for Acidic Methanol Oxidation

“…As such, ternary metal composites are a reasonable system, as Pt and Ru loadings can be effectively varied. There are several reports on ternary metal composites for the MOR; however, the onset potential for the MOR of these catalysts is still higher than 0.6 V RHE due to the absence of Ru or the heterogeneous distribution of Ru. , Moreover, when transition metals are employed in acids, one unavoidable problem is that the catalyst will gradually transform under acidic conditions through processes such as rearrangement and partial dissolution. − Thus, finding a suitable substrate, regulating the loading of Pt, and investigating the change of catalyst under acidic conditions are of significance for the rational design of MOR catalysts.…”