TY - JOUR
T1 - Microwave-Assisted Synthesis and Characterization of γ-MnO2 for High-Performance Supercapacitors
AU - Cuéllar-Herrera, Lorena
AU - Arce-Estrada, Elsa
AU - Romero-Serrano, Antonio
AU - Ortiz-Landeros, José
AU - Cabrera-Sierra, Román
AU - Tirado-López, Cindy
AU - Hernández-Ramírez, Aurelio
AU - López-Rodríguez, Josué
N1 - Publisher Copyright:
© 2021, The Author(s).
PY - 2021/10
Y1 - 2021/10
N2 - Two hydrothermal techniques under microwave irradiation were used to synthesize γ-MnO2 from 90°C to 150°C in 10−30 min. The first technique is based on reducing KMnO4 with MnSO4, and the second one involves liquid-phase oxidation between MnSO4 and (NH4)2S2O8. The structures and morphologies of the samples were analyzed using X-ray diffraction, scanning electron microscopy, and N2 physisorption measurements. The electrochemical properties were evaluated through cyclic voltammetry and electrochemical impedance spectroscopy. The γ-MnO2 materials obtained by the first technique mainly exhibited nanorods with diameters of 40–60 nm, and the samples obtained by the second technique showed flower-like microspheres with diameters of 1−2 µm; each flower was composed of nanosheets with a thickness of 10−20 nm. The processing time directly depends on the size of the nanorods. The sample synthesized by the first technique at 150°C and 10 min has the highest specific surface area of up to 59.08 m2 g−1 and mean pore diameter of 34.11 nm. Furthermore, this sample exhibits a near-rectangular cyclic voltammetry curves and high specific capacitance of 331.3 F g−1 in 0.1 M Na2SO4 solution at 5 mV s−1 scan rate. Graphic abstract: [Figure not available: see fulltext.].
AB - Two hydrothermal techniques under microwave irradiation were used to synthesize γ-MnO2 from 90°C to 150°C in 10−30 min. The first technique is based on reducing KMnO4 with MnSO4, and the second one involves liquid-phase oxidation between MnSO4 and (NH4)2S2O8. The structures and morphologies of the samples were analyzed using X-ray diffraction, scanning electron microscopy, and N2 physisorption measurements. The electrochemical properties were evaluated through cyclic voltammetry and electrochemical impedance spectroscopy. The γ-MnO2 materials obtained by the first technique mainly exhibited nanorods with diameters of 40–60 nm, and the samples obtained by the second technique showed flower-like microspheres with diameters of 1−2 µm; each flower was composed of nanosheets with a thickness of 10−20 nm. The processing time directly depends on the size of the nanorods. The sample synthesized by the first technique at 150°C and 10 min has the highest specific surface area of up to 59.08 m2 g−1 and mean pore diameter of 34.11 nm. Furthermore, this sample exhibits a near-rectangular cyclic voltammetry curves and high specific capacitance of 331.3 F g−1 in 0.1 M Na2SO4 solution at 5 mV s−1 scan rate. Graphic abstract: [Figure not available: see fulltext.].
KW - Mesoporous MnO
KW - high capacitance
KW - hydrothermal
KW - microwave-assisted
UR - http://www.scopus.com/inward/record.url?scp=85111494975&partnerID=8YFLogxK
U2 - 10.1007/s11664-021-09098-x
DO - 10.1007/s11664-021-09098-x
M3 - Artículo
AN - SCOPUS:85111494975
SN - 0361-5235
VL - 50
SP - 5577
EP - 5589
JO - Journal of Electronic Materials
JF - Journal of Electronic Materials
IS - 10
ER -