Sustainable development of graphene oxide from pine leaves for electrochemical energy storage and corrosion protection
Kavita Singhal, Sameena Mehtab, Minakshi Pandey, M.G.H. Zaidi
Abstract
Present investigation demonstrates application of pine leaves as green friendly source for production of biochar (BC) that has been further transformed into graphene oxide (GO). BC and respective GO has been investigated for sustained electrochemical energy storage (EES) and corrosion protection in KOH (2.0 M). For this purpose, BC was prepared through pyrolysis of pine leaves (moisture content 78.09%) at 750 °C over 3 h in nitrogen environment. GO was synthesized through modification in Hummer's method. Formation of BC and GO was ascertained through Fourier transform infrared, Raman and X-ray diffraction spectra. Working electrodes (WE) were fabricated from BC (WEBC) and GO (WEGO) in presence of hydroxy methyl propyl cellulose as binder and their morphologies were compared through scanning electron microscopy. WE were electrochemically analyzed through cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and potentiodynamic polarization in KOH (2.0 M). CV @ 0.005 V/s in potential window of −0.71 V to −0.21 V reveals 390.4 F/g of Cs of WEGO that was 24.49% improved over WEBC. EIS in frequency response (KHz) ranging 1.0 × 10−5 Hz to 100 at ± 0.005 V reveals stability of WE over 24 h. Potentiodynamic polarization in the potential ranging −1.5 to 1.0 @ 0.005 V/s reveals corrosion rate (mm/year) of WEGO @ 4.69 × 10−4 that was much reduced over WEBC (2.27 × 10−3) under identical conditions.