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

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 °C (BMG-c). The structural and compositional changes of the BMG were investigated by XRD, Raman, XPS, and N₂ adsorption-desorption isotherm measurements. The materials obtained have high BET specific surface area of up to 1102 m² g⁻¹ for BMG-c, and 997 m² 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.