Conversion of acrylic/wool fibers to N-doped carbon materials for adsorption and electrochemical oxygen reduction to hydrogen peroxide

Pyrolysis cum activation of stabilized acrylic/wool textile waste allows generation of new nitrogen doped porous carbons for applications in wastewater purification by adsorption or in electrocatalysis as alternative to the Pt/C-based catalysts for the oxygen reduction reaction (ORR). It was demonstrated that by the fine tuning of the stabilization and pyrolysis conditions the final porosity of the produced carbons as well as the ratio of pyridinic to graphitic nitrogen can be favourable customized for specific applications. The porous carbon obtained after 1 h stabilization at 260°C under air and pyrolysis for 1 h at 800°C under nitrogen with KOH as activator, although it exhibited only the second largest specific surface area of ∼ 1465 m 2 /g, presented the highest adsorption capacities towards 4-chlorophenol (1000 mg/g) and methylene blue (714 mg/g) from water. The same material exhibited also the best performance in a gas diffusion electrode-based electrochemical cell. With respect to a high electrocatalytic activity of the obtained carbons in the ORR reaction, a positive correlation with the specific surface area was observed suggesting an increased number of active sites with superior electrocatalytic activity.