2 research outputs found
Impact on the Photocatalytic Dye Degradation of Morphology and Annealing-Induced Defects in Zinc Oxide Nanostructures
In this study, three
different morphologies, nanoflower (NF), nano
sponge (NS), and nano urchin (NU), of zinc oxide (ZnO) nanostructures
were synthesized successfully via a mild hydrothermal method. After
synthesis, the samples were annealed in the atmosphere at 300, 600,
and 800 °C. Although annealing provides different degradation
kinetics for different morphologies, ZnO NS performed significantly
better than other morphologies for all annealing temperatures we used
in the study. When the photoluminescence, electron paramagnetic resonance
spectroscopy, BET surface, and X-ray diffraction analysis results
are examined, it is revealed that the defect structure, pore diameter,
and crystallinity cumulatively affect the photocatalytic activity
of ZnO nanocatalysts. As a result, to obtain high photocatalytic activity
in rhodamine B (RhB) degradation, it is necessary to develop a ZnO
catalyst with fewer core defects, more oxygen vacancies, near band
emission, large crystallite size, and large pore diameter. The ZnO
NS-800 °C nanocatalyst studied here had a 35.6 × 10–3 min–1 rate constant and excellent
stability after a 5-cycle photocatalytic degradation of RhB
Nitrogen-Doped WO<sub>3</sub> Nanoparticles as Electrode Materials in All-in-One Supercapacitor Devices
The
effect of the annealing temperature on 1% nitrogen-doped WO3 materials was studied, which were then used as electrode
materials for high-performance supercapacitor (SC) devices. The supercapacitive
performance of the proposed materials was strongly influenced by the
doping element and the annealing temperature by directly changing
the defect structure of the host material. The 1% N-doped WO3 materials annealed at different temperatures were thoroughly characterized
through various characterization techniques, including electron paramagnetic
resonance and photoluminescence spectroscopy, giving insight into
the effect of N-doping on the defect structure and optical properties
of WO3. When the WO3:N materials were used as
electrode material in symmetric SCs, the doping element and the annealing
temperature improved the electrochemical performance. No booster materials
(such as carbon black) were used in the symmetric SC designs, showing
increased specific capacitance (102 F/g) and energy density (14.6
W h/kg) values