Nanoporous Heteroatom-Doped Carbons Derived from Cotton Waste: Efficient Hydrazine Oxidation Electrocatalysts

In this work, cotton-based denim waste is successfully used as a precursor to synthesize nanoporous P- and N-co-doped carbon materials that can serve as efficient electrocatalysts for the hydrazine oxidation reaction (HzOR). In the synthesis, the cotton denim waste is mixed with H3PO4 in two different denim/H3PO4 (wt/vol) ratios, namely, 1:1 and 1:3, wherein H3PO4 serves as both an activating agent and a source of P dopant atoms while the indigo carmine dye present in denim serves as a source of N dopant atoms to the carbon materials. The resulting P- and N-co-doped carbon materials, named PNC1 and PNC3, respectively, are characterized by various analytical techniques. The XPS spectra show that PNC1 has ca. 2.17 atomic % P and 1.95 atomic % N whereas PNC3 has 2.54 atomic % P and 0.71 atomic % N. Pore analyses by N2 porosimetry indicate that PNC1 has a higher surface area (1582 m2 g–1) than PNC3 (486 m2 g–1), although the former has a lower mesopore volume (0.39 cm3 g–1) than the latter (0.58 cm3 g–1). The...