Generation of hierarchical N-doped porous carbons from textile fabrics based on acrylic/wool fiber mixtures

Porous nitrogen-doped carbons with hierarchical structure, large specific surface area and tunable functional groups are very interesting for water purification via adsorption or for the development of metal-free electrocatalysts for the oxygen reduction reaction (ORR). With the motivation to enable the utilization of textile waste, in the present work the potential and the difficulties associated with the generation of such N-doped porous carbons from consumer textile fabrics based on acrylic/wool fiber mixtures was investigated in detail. Morphological analysis revealed that the obtained carbons have a hierarchical porous structure with interconnected pores at multiple size scales. The best performing carbon material produced in this work, with a specific surface area of 2534 m 2 /g, exhibited very high maximal adsorption capacities for methylene blue (625 mg/g), rhodamine B (667 mg/g) and 4-chlorophenol (588 mg/g) from water. The same material showed also potential as highly selective catalyst for the 4 e - ORR process with a faradaic efficiency of ∼ 80% for the 4 e - process. As all N-doped porous carbons generated in this work performed very well in all studied adsorption tests, the proposed carbonization process was considered adequate for adsorber preparation. However, given the variability introduced by different precursors and additives, predicting the ORR selectivity toward 2- or 4-electrons remains a significant challenge.