KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Karaphun, AttapholSubject: search.filters.subject.Nanocomposite

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Structural, morphological, optical, and electrochemical properties of Zn-doped CeO2/rGO nanocomposites
    (2025-04-01)
    Utara, Songkot
    ;
    Salidkul, Nuchjaree
    ;
    Karaphun, Attaphol
    ;
    Sonsupap, Somchai
    ;
    Chanlek, Narong
    Metal-doped cerium oxide has recently attracted the interest of researchers worldwide because of its various applications in different fields such as supercapacitors, high-sensitivity electrodes or photocatalytic. Metal-doped cerium oxide can be improved utilizing a variety of metals and composites with enhanced conductivity, which advances materials science in semiconductor processing. In this study, undoped and Zn-doped CeO<inf>2</inf> nanoparticles at 5, 10, 15, and 20 at.% were reacted with reduced graphene oxide (rGO) using a hydrothermal method. They were heated at 150 °C for 12 h and then processed in an ultrasonic reactor (20 kHz) at 25 ± 1 °C. Their structural, morphological, elemental, optical, and electrochemical properties were systematically characterized. The calculated average crystallite sizes of CeO<inf>2</inf> peaks ranged from 4.60 ± 0.2 to 12.0 ± 0.4 nm. These samples exhibited a single CeO<inf>2</inf> phase corresponding to a face-centered cubic structure, except for 20 at.% Zn-doped CeO<inf>2</inf>/rGO, which presented a ZnO phase. The samples had lower band gap values than expected for undoped CeO<inf>2</inf> nanoparticles, higher valence states due to their Ce<sup>3+</sup>/Ce<sup>4+</sup> ratios, and a large surface area, 242 m<sup>2</sup>/g, due to Zn-doping in CeO<inf>2</inf> samples. The highest specific capacitance values achieved were 88.49 F/g at 5 mV/s and 134.01 F/g at 0.5 A/g for undoped CeO<inf>2</inf>/rGO. Zn-doping resulted in decreased capacitive behavior with specific capacitance values in the range of 70.78–81.00 F/g at 5 mV/s and 79.24–101.43 F/g at 0.5 A/g. This study for synthesizing Zn/CeO<inf>2</inf>/rGO ternary nanocomposites produced materials with improved band gaps, valence states of Ce<sup>3+</sup>/Ce<sup>4+</sup> ratios, and greater surface area for improved electrocatalytic performance.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Ag nanomaterials deposited reduced graphene oxide nanocomposite as an advanced hybrid electrode material for Asymmetric Supercapacitor device
    (2020-12-30)
    Tuichai, Wattana
    ;
    Karaphun, Attaphol
    ;
    Ruttanapun, Chesta
    Asymmetric Supercapacitor (ASC) was effectively fabricated using CR 2032-coin cell based on the positive electrode of the hybrid Ag@rGO nanocomposite and the negative electrode of reduced Graphene Oxide (rGO) material with polyvinyl alcohol (PVA)/6 M KOH electrolyte. The Ag@rGO nanocomposite was prepared through a seed-mediated growing process by a 10 wt% of Ag nanomaterials deposits in suspension rGO 90 wt% which presented a specific capacitance value of 65.9 F g<sup>−1</sup> at current density of 0.5 A g<sup>−1</sup>. Moreover, the rGO electrode with a 5 mg/mL concentration was synthesized by the modified Hummers’ method and revealed a high specific capacitance value of 317.3 F g<sup>−1</sup> at current density of 0.5 A g<sup>−1</sup>. Interestingly, the ASC assembly of Ag@rGO//rGO hybrid energy-storage device provided a wide voltage window of 0.0–1.4 V and showed a specific capacitance (C<inf>sc</inf>) value of 44.17 F g<sup>−1</sup> at current density of 3 A g<sup>−1</sup>. This hybrid energy-storage device indicated specific energy density (E<inf>sp</inf>) of 11.09 W h kg<sup>−1</sup> and specific power density (P<inf>sp</inf>) of 2.67 kW kg<sup>−1</sup>, respectively. It also showed a good cycle stability of 81.5%. The capacitance retention finished at 500 cycles.