TY - JOUR

T1 - A complex study of the dependence of the reduced graphite oxide electrochemical behavior on the annealing temperature and the type of electrolyte

AU - Iurchenkova, Anna A.

AU - Lobiak, Egor V.

AU - Kobets, Anna A.

AU - Kolodin, Alexey N.

AU - Stott, Ash

AU - Silva, S. Ravi P.

AU - Fedorovskaya, Ekaterina O.

N1 - Publisher Copyright: © 2021 Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/2/20

Y1 - 2021/2/20

N2 - In this work we investigate the influence of thermal treatment of reduced graphite oxide (RGO) on its functional composition and electrochemical performance. It is found that carboxyl, carbonyl, hydroxyl and epoxy groups are present on the RGO surface, witch when subject to thermal annealing in the temperature range 230–250°C can be controllably modified. In the process of thermal annealing, we show the formation of quinoid groups due to an increase in the number of defects. Decrease of the number of layers in RGO material and the quantity of oxygen-containing functional groups (OCFG) also occurs. With increase in annealing temperature, sequential removal of OCFG occurs as follows: carboxyl (250°C–600°C), hydroxyl (600°C–800°C), carbonyl and quinoid (700°C–1000°C). Electrochemical measurements over a wide range of pH values of the buffer electrolytes is possible to correlate the peaks in the cyclic voltammogram curves with the redox reactions of oxygen-containing functional groups as a function of applied potential. Peaks correlated with specific redox reactions which are identified as two-electron. The dependence of the specific capacities of materials on the electrolyte type has been studied. Highest capacitance was detected in 1M NaOH at a scan rate 2 mVs−1 and is equal to 210 Fg−1.

AB - In this work we investigate the influence of thermal treatment of reduced graphite oxide (RGO) on its functional composition and electrochemical performance. It is found that carboxyl, carbonyl, hydroxyl and epoxy groups are present on the RGO surface, witch when subject to thermal annealing in the temperature range 230–250°C can be controllably modified. In the process of thermal annealing, we show the formation of quinoid groups due to an increase in the number of defects. Decrease of the number of layers in RGO material and the quantity of oxygen-containing functional groups (OCFG) also occurs. With increase in annealing temperature, sequential removal of OCFG occurs as follows: carboxyl (250°C–600°C), hydroxyl (600°C–800°C), carbonyl and quinoid (700°C–1000°C). Electrochemical measurements over a wide range of pH values of the buffer electrolytes is possible to correlate the peaks in the cyclic voltammogram curves with the redox reactions of oxygen-containing functional groups as a function of applied potential. Peaks correlated with specific redox reactions which are identified as two-electron. The dependence of the specific capacities of materials on the electrolyte type has been studied. Highest capacitance was detected in 1M NaOH at a scan rate 2 mVs−1 and is equal to 210 Fg−1.

KW - Cyclic voltammetry

KW - Fourier transform infrared spectroscopy

KW - Graphite oxide

KW - Reduced graphite oxide

KW - Supercapacitor

KW - X-ray photoelectron spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=85099691794&partnerID=8YFLogxK

U2 - 10.1016/j.electacta.2021.137832

DO - 10.1016/j.electacta.2021.137832

M3 - Article

AN - SCOPUS:85099691794

VL - 370

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

M1 - 137832

ER -