Small pieces of
carbonaceous nanofiber hydrogels were soaked successively in ethanol (12 h 3 5
times), acidic H2O2 solution (HCl: H2O2: H2O 5 2:5:23, v/v, 12 h), and deionized
water (12 h 3 5 times) at room temperature to remove impurities and TeNWs
templates.