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Multi-phase structure electrospun CNF@Ag/Mn/Bi/Fe composite nanofiber enhanced supercapacitor behavior
(2025-02-15)
Sinprachim, Tanayt
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Klompong, Narit
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Chanlek, Narong
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Kidkhunthod, Pinit
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Maensiri, Santi
This study presents the development of carbon-based multiphase metal oxide nanocomposites (CNF@MO<inf>x</inf>; M = Ag, Mn, Bi, and Fe) incorporating silver, manganese, bismuth, and iron nanoparticles within polyacrylonitrile (PAN)-derived carbon nanofibers. These nanocomposites were fabricated via the electrospinning technique with metal oxide concentrations of 10, 20, and 40 %w. This was followed by annealing in an argon atmosphere. The resulting nanofibers exhibited diameters ranging from 559 to 830 nm, with embedded nanoparticles measuring from 9 to 21 nm. Comprehensive characterization revealed that the nanofibers possessed uniform morphology, high porosity, and robust thermal stability. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) confirmed the valence states of the metal oxides (Ag⁰, Bi³⁺, Mn²⁺, Mn³⁺, Fe²⁺, and Fe³⁺), which are integral to redox reactions and charge storage mechanisms. Among the fabricated composites, CNF@Ag/Mn/Bi/Fe-20 demonstrated the best electrochemical performance, achieving a specific capacitance of 156 F g−1 at a scan rate of 2 mV s−1 and outstanding cycling stability with a capacity retention of over 96 % after 1400 charge-discharge cycles. The synergistic combination of double-layer capacitance and pseudocapacitance mechanisms in these nanofibers represents a significant improvement over conventional electrode material. This study highlights CNF@Ag/Mn/Bi/Fe nanocomposites as highly promising candidates for advanced energy storage applications, particularly in supercapacitor technologies.
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Treatment of Lignin Wastewater Using Peroxydisulfate Combined with Manganese Oxide-Loaded Biochar
(2022-09-01)
Suwannarat, Glinsukol
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Sontabam, Kemason
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Sawangying, Soraya
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Chaiyaraksa, Chompoonut
The pulp and paper industry wastewater discharge into public water, it will cause water pollution problems. In this research, lignin contaminated synthetic wastewater with a COD value of 2,401 mg/L, and color intensity of 5,432 ADMI was treated using 150 mM sodium peroxydisulfate in combination with MnO<inf>x</inf>-loaded biochar (MnO<inf>x</inf>-B). The MnO<inf>x</inf>-B was produced by pyrolyzing corn core at 400 °C for 4 hours without oxygen, then dipped in 40 mM manganese sulfate for 2 hours, and heated at 600°C for 30 min without oxygen. From the characterization of MnO<inf>x</inf>-B, the surface area, pore volume, pore size, and pH value at the zero-point charges of MnO<inf>x</inf>-B were 153 m2/g, 0.054 cm3/g, 1.11 nm, and 7.23, respectively. From the FTIR spectrogram, the peak assigned to Mn-O was observed. By applying 150 mM sodium peroxydisulfate and varying three parameters: MnO<inf>x</inf>-B dosage, initial wastewater pH, and reaction time, to treat lignin wastewater, the optimum experimental condition was obtained using 2 mg/L of MnO<inf>x</inf>-B, under pH of 8 for 45 min. The COD and color removal efficiencies were 73% and 90%, respectively. However, the quality of the treated wastewater did not yet pass the pulp and paper mills effluent standards of the Department of Industrial Works.
1
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Carbon nanotube/manganese oxide thin film composites-based counter electrode for dye-sensitized solar cell
(2016-01-01)
Nathakreat, Ketama
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Wirat, Jarernboon
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Winadda, Wongwiriyapan
Manganese oxide thin film sandwiched between carbon nanotubes thin films-coated on fluorine-doped tin oxide (FTO/CNT/MnO<inf>x</inf>/CNT) was used as a counter electrode of dye-sensitized solar cell (DSSC) for performance improvement. The multi-layer electrodes were fabricated by sequential process comprising doctor-blade coating of CNT layer and the following electroplating coating of MnO<inf>x</inf> layer and subsequent doctor-blade coating of CNT layer once again. The multi-layered counter electrode of CNT/MnO<inf>x</inf>/CNT exhibited the improved conversion efficiency and a fill factor of 2.01±0.01% and a fill factor of 0.55±0.01, respectively, due to an increase in capacitance of the electrode. Electrochemical impedance spectra (EIS) show that the capacitance of multi-layered CNT/MnO<inf>x</inf>/CNT electrode increased from 22±3 μF to 41±2 μF comparing to that of a monolayer of CNT. Furthermore, EIS of FTO/CNT/MnO<inf>x</inf>/CNT-based DSSC shows the smallest radius of the semicircle with a charge transfer resistance of 42 ω, implying a quick redox reaction between counter electrode and electrolyte. The improved fill factor is likely due to the role of MnO<inf>x</inf> that increases the capacitance of electrode and reduces electron transfer rate from counter electron to electrolyte.
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Electrodeposition of manganese oxide nanosheets as supercapacitor electrode materials
(2016-01-01)
Thanthamrong, Wanchaem
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Songsak, Rattanamai
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Paweena, Dulyaseree
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Wirat, Jarernboon
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Winadda, Wongwiriyapan
Manganese oxide (MnO<inf>x</inf>) thin films were prepared on stainless steel (SS) 304 by galvanostatic (GS) mode of electrodeposition technique using different precursors; 0.1 M potassium permanganate (KMnO<inf>4</inf>) and 0.1 M manganese sulfate (MnSO<inf>4</inf>) solutions. The electrodeposition condition was set at a constant current of 1 mA/cm2. Different precursors provide MnO<inf>x</inf> thin films with different morphologies. Using KMnO<inf>4</inf> as a precursor, the MnO<inf>x</inf> thin film was deposited (MnO<inf>x</inf>-K), while using MnSO<inf>4</inf> as a precursor, the MnO<inf>x</inf> nanosheets with a thickness of approximately 40 nm were formed (MnO<inf>x</inf>-S). XPS results evidence the formation of manganese oxide with different oxidation states composition by different precursors. Electrochemical measurements were carried out in a three-electrode setup using Pt and Ag/AgCl electrodes as counting and reference electrodes, respectively and 1M Na<inf>2</inf>SO<inf>4</inf> aqueous solution as electrolyte. MnO<inf>x</inf>-K at a deposition time of 10 min shows the highest specific capacitance of 233.55±19.01 F/g. The specific capacitance improvement of MnO<inf>x</inf>-K may be attributed to MnO<inf>x</inf> nanosheet structure which increases surface area of electrode.

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