TY - JOUR
T1 - One-step, low temperature synthesis of reduced graphene oxide decorated with ZnO nanocrystals using galvanized iron steel scrap
AU - Tolentino-Hernandez, R. V.
AU - Jimenez-Melero, E.
AU - Espinosa-Faller, F. J.
AU - Guarneros-Aguilar, C.
AU - Caballero-Briones, F.
N1 - Publisher Copyright:
© 2021 The Author(s). Published by IOP Publishing Ltd.
PY - 2021/6
Y1 - 2021/6
N2 - Production of a ZnO-rGO composite, using a novel one-pot method consisting in continuously flowing argon into a GO aqueous suspension heated at 80 C, in the presence of galvanized iron steel scrap is presented. FTIR shows the complete disappearance of GO functional groups and only the C=C band remained, indicating extensive GO reduction. Raman spectra indicated sp2 character increase after reaction and the presence of the E2h mode of ZnO. SEM showed submicron crystals identified by XRD as ZnO in the hexagonal phase, while TEM images indicate ZnO nanoparticles decorate mainly the rGO borders. Optical band gap of 3.5 eV corresponding to ZnO, and optical transitions at 4.1 and 5.5 eV related with n → π and π → π∗ were observed. Electrochemical characterization by cyclic voltammetry shows an specific capacitance of 4.7 F g-1 at a scan rate of 5 mVs-1, which drops to ca. 0.8 F g-1 at 200 mVs-1. By electrochemical impedance spectroscopy, the relaxation time was ca. 5 ms. The proposed mechanism for the materials' synthesis includes Zn dissolution from scrap, galvanic displacement of oxygen moieties at the GO sheet, Zn deposition onto the carbon surface, and further oxidation and growth of ZnO nanocrystals.
AB - Production of a ZnO-rGO composite, using a novel one-pot method consisting in continuously flowing argon into a GO aqueous suspension heated at 80 C, in the presence of galvanized iron steel scrap is presented. FTIR shows the complete disappearance of GO functional groups and only the C=C band remained, indicating extensive GO reduction. Raman spectra indicated sp2 character increase after reaction and the presence of the E2h mode of ZnO. SEM showed submicron crystals identified by XRD as ZnO in the hexagonal phase, while TEM images indicate ZnO nanoparticles decorate mainly the rGO borders. Optical band gap of 3.5 eV corresponding to ZnO, and optical transitions at 4.1 and 5.5 eV related with n → π and π → π∗ were observed. Electrochemical characterization by cyclic voltammetry shows an specific capacitance of 4.7 F g-1 at a scan rate of 5 mVs-1, which drops to ca. 0.8 F g-1 at 200 mVs-1. By electrochemical impedance spectroscopy, the relaxation time was ca. 5 ms. The proposed mechanism for the materials' synthesis includes Zn dissolution from scrap, galvanic displacement of oxygen moieties at the GO sheet, Zn deposition onto the carbon surface, and further oxidation and growth of ZnO nanocrystals.
KW - GO reduction
KW - Galvanic displacement
KW - Spontaneous reaction
KW - ZnO-rGO
UR - http://www.scopus.com/inward/record.url?scp=85109649287&partnerID=8YFLogxK
U2 - 10.1088/2053-1591/ac0c9c
DO - 10.1088/2053-1591/ac0c9c
M3 - Artículo
AN - SCOPUS:85109649287
SN - 2053-1591
VL - 8
JO - Materials Research Express
JF - Materials Research Express
IS - 6
M1 - 065010
ER -