Electrochemical behavior of boron-doped mesoporous graphene depending on its boron configuration

Abstract

Boron-doped mesoporous graphene (BMG) was synthesized via a hydrothermal process (BMG-h), utilizing the soft-template route tri-block co-polymer P123. To control the porous structure and boron configuration (BCO2 and BC2O) of the graphitic domain, the obtained BMG-h was calcined at 1000 degrees C (BMG-c). The structural and compositional changes of the BMG were investigated by XRD, Raman, XPS, and N-2 adsorption-desorption isotherm measurements. The materials obtained have high BET specific surface area of up to 1102 m(2) g(-1) for BMG-c, and 997 m(2) g(-1) for BMG-h. With the heat treatment, there was an increase in specific surface area, and a decrease in oxygen contents. Herein, calcination was introduced to control the boron configuration. From the XPS survey spectra, the atomic composition of the BMG-h was C (70.6 at%), O (16.4 at%), and B (12.9 at%), while that of the BMG-c was C (73.3 at%), O (15.1 at%), and B (11.5 at%). From B1s fitting analysis, BMG-h was dominant in the BCO2 configuration. However, on heat treatment, BCO2 peak reduction occurs during the thermal process, thus BC2O was prevalent in the graphene lattice of the BMG-c samples. We successfully controlled the specific surface area and configuration of boron in mesoporous graphene. BMG-h has more pseudo-capacitance behavior than BMG-c, because of the high boron and oxygen contents. Therefore, the control of porous structure and the boron configuration of BMG played an important role in providing the good specific capacitance of 336 F g(-1) for the BMG-h, and 169 F g(-1) for BMG-c, at a specific current density of 0.1 A g(-1).