Synthesis and thermoelectric properties of RuO2 nanorods

Abstract

We have explored the effect of the O/Ru ratio on the morphology and the Seebeck coefficient of RuO2 nanorods (space group P42/mnm) synthesized by reactive sputtering. At an O/Ru ratio of 1.69, a faceted surface is observed, while nanorod formation occurs at O/Ru ratios of 2.03 and 2.24. Using classical molecular dynamics with the potential parameters derived in this work, we show that volatile species enable nanorod formation. Based on ab initio calculations, two effects of the nanorod formation on the Seebeck coefficient are observed: (i) increase due to additional states in the vicinity of the Fermi level and (ii) decrease due to oxygen point defects (volatile species). These two competing effects give rise to a moderate increase in the Seebeck coefficient upon nanorod formation.

Atomistic growth phenomena of reactively sputtered RuO2 and MnO2 thin films

“…When an additional Ru is added onto RuO 2 (110) with already adsorbed Ru and dissociated O 2 molecule, it is desorbed. This excess of oxygen is consistent with hyperoxide formation, 12,14,15 which is relevant for nucleation of RuO 2 nanorods.…”

“…This is consistent with previous work. 12,14 Based on the comparison with literature on RuO 2 nanorods, 12,14-16 it may be speculated that RuO 2 nanorods shown in Fig. 2 deviations is to be expected for polycrystalline aggregates where one morphological feature contains several coherency domains.…”

RuO2 Nanorods on Electrospun Carbon Nanofibers for Supercapacitors

“…It has an excellent specific capacitance higher than 700 F g –1 , stable electrochemical reversibility, and high rate capability in aqueous electrolytes due to the multiple reversible redox states of RuO 2 electrodes. − Recently, there has been growing interest in hybridized one-dimensional (1D) RuO 2 nanorods on carbon materials, which exhibit high performance in energy applications. Various synthetic methodologies to combine 1D RuO 2 nanorods with carbon materials have been presented, e.g., the sputtering technique, hydrothermal method, and vapor deposition process. − However, these methods are very expensive and require complicated multistep preparation, which cannot satisfy the requirements for commercial applications.…”

Determining the Elasticity of Materials Employing Quantum‐mechanical Approaches: From the Electronic Ground State to the Limits of Materials Stability

“…In such multi‐scale modelling of materials or scale‐hopping approaches, the role of ab initio calculations is mostly two‐fold: (i) to study the cases where the electronic effects are crucial and must be treated from first principles and (ii) to provide data for the generation of inter‐atomic potentials with an extended range of transferability (see e.g. 5). Let us note that there exists a vast amount of literature devoted to multiscale modelling of materials (recent reviews may be found for example in 6–9).…”