부산대학교 도서관

This letter reports the synthesis of RuO2nanocrystals by the anionic surfactant-assisted hydrothermal method at 90 °C for24 h followed by heat treatment at 500 °C for 1 h. These crystals were structurally characterized by means of X-ray diffraction(XRD) and Rietveld refinement analysis. Field emission scanning electron microscopy (FE-SEM) was employed to observethe morphological features these crystals. The optical behavior was investigated by ultraviolet–visible (UV–Vis) spectroscopy. First-principles quantum mechanical calculations based on the density functional theory at the B3LYP level wereemployed to obtain the electronic band structure and density of states. For electrochemical behavior, the supercapacitorproperties of RuO2crystals were investigated by cyclic voltammetry. XRD patterns and Rietveld refinement data indicatethat RuO2crystals have a rutile-type tetragonal structure. FE-SEM images showed the presence of sphere-like RuO2crystalswith an average crystal sized at around 19.13 nm. The experimental band gap energy (Egap[exp]) was estimated at 2.60 eV byusing UV–Vis spectroscopy, while the theoretical calculations indicate an Egap[theo] at 1.92 eV. These calculations revealed aband structure predominantly composed of O 2p orbitals (valence band) and Ru 4d orbitals (conduction band). The specificcapacitance measured for RuO2film was 193 F g−1 at 5 mV s−1 in an electrode with 0.5 mg of electroactive material in 1 MNa2SO4solution.
This letter reports the synthesis of RuO2nanocrystals by the anionic surfactant-assisted hydrothermal method at 90 °C for24 h followed by heat treatment at 500 °C for 1 h. These crystals were structurally characterized by means of X-ray diffraction(XRD) and Rietveld refinement analysis. Field emission scanning electron microscopy (FE-SEM) was employed to observethe morphological features these crystals. The optical behavior was investigated by ultraviolet–visible (UV–Vis) spectroscopy. First-principles quantum mechanical calculations based on the density functional theory at the B3LYP level wereemployed to obtain the electronic band structure and density of states. For electrochemical behavior, the supercapacitorproperties of RuO2crystals were investigated by cyclic voltammetry. XRD patterns and Rietveld refinement data indicatethat RuO2crystals have a rutile-type tetragonal structure. FE-SEM images showed the presence of sphere-like RuO2crystalswith an average crystal sized at around 19.13 nm. The experimental band gap energy (Egap[exp]) was estimated at 2.60 eV byusing UV–Vis spectroscopy, while the theoretical calculations indicate an Egap[theo] at 1.92 eV. These calculations revealed aband structure predominantly composed of O 2p orbitals (valence band) and Ru 4d orbitals (conduction band). The specificcapacitance measured for RuO2film was 193 F g−1 at 5 mV s−1 in an electrode with 0.5 mg of electroactive material in 1 MNa2SO4solution.