Structurally Controllable Hay-Slag-Based Porous Carbons for Supercapacitor and CO₂ Adsorption Applications

Biomass-derived porous carbon materials were selectively and controllably prepared by carbonization of hay slag (HS) and activation with ZnCl2 combined with Mg(NO[Formula: see text]H2O. The prepared porous carbon materials had an apparent multi-pore structure and a large specific surface area. In a 6[Formula: see text]mol/L KOH with a current density of 0.25[Formula: see text]A/g, the specific capacitance of the prepared sample was 220[Formula: see text]F/g. Further study showed that the optimal pore size range of porous carbon materials for electrode preparation was 0.8–1.2[Formula: see text]nm. At the same time, the porous carbon material had a good adsorption capacity for CO2, and the adsorbent performance was 3.09[Formula: see text]mmol/g at 0∘C and 1 bar. Adsorbents with the pore size range of 0.5–0.8[Formula: see text]nm had the best CO2 adsorption performance. This integrated strategy study expanded biomass-derived porous carbon materials with controllable pore structures to match different application strategies.