Co-doping mechanism of biomass-derived nitrogen-boron porous carbon and its applications in energy storage and environmental purification

In this paper, we aim to design and synthesize a low-cost, multifunctional and efficient electrode and adsorbent material (nitrogen doped and nitrogen-boron co-doped) by combinatorial doping of heteroatoms using cherry blossoms (Prunus yedoensis) as biomass feedstock. The differences in morphology and structure of the two materials due to the doping of boron atoms were analyzed. Among them, the nitrogen-boron co-doped porous carbon NBKCC had a hierarchical porous structure with a shape similar to that of carbon microspheres and a specific surface area as high as 1184 m2/g. In the three-electrode system, the specific capacitance of the assembled electrodes was 337.5 F/g (current density: 0.5 A/g). In the NBKCC symmetric capacitor test, the energy density could reach 15.1 Wh/kg at a power density of 420.5 W/kg. After 10,000 charge/discharge cycles, the capacitance retention was 96.98% (5 A/g), which showed good stability. In addition, we evaluated the adsorption capacity of carbon microspheres for malachite green, rhodamine B, and methylene blue. Among them, the maximum adsorption of malachite green in a single system was 572.2 mg/g. Based on this, we demonstrated the feasibility and preparation of porous carbon materials by combinatorial doping with heteroatoms using biomass waste cherry blossoms as carbon substrates.