Synergetic Effect of Microporosity, Composition, and Surface Functionality of Nanoporous Activated Carbon: An Interface for CO₂ Capture and Supercapacitor Applications

The current study involves the value-based conversion of waste floral foam into nanoporous activated carbon (NAC), which can be employed as a bifunctional material as a CO2 adsorbent and an electrode for supercapacitors. The waste floral foam is first subjected to acid pickling and then thermally activated at various temperatures (500–800 °C) under a N2 atmosphere. The resultant optimum sample, NAC700, has a high surface area of 732 m2/g, an abundance of narrow micropores (≤0.8 nm), and rich surface oxygen functionality. Owing to its array of synergistic attributes, the optimum sample NAC700 exhibits an excellent CO2 capture capacity of 3.22 mmol/g at 15 °C and 1 bar. Simultaneously, NAC700 also delivers a good specific capacitance of 116 F/g at 5 mV/s and 187 F/g at 0.2 A/g, as calculated from CV and GCD data, respectively, in 1 M KOH. The strategy proposed here offers a facile pore manipulation technique for fabricating nanoporous activated carbon with substantial potential for CO2 capture and energy storage applications while neutralizing waste floral foam.