were of analytical grade and were used without further purification.
H2O2 (30%), FeCl3·6H2O, N,N-dimethyl formamide (N,N-DMF), methanol, isopropyl alcohol,
and NaOH were purchased from Damao Chemical Reagent Factory (Tianjin,
China) and Fuyu Chemical Co., Ltd. (Tianjin, China). tert-Butyl alcohol (TBA) was obtained from Bodi Chemical Co., Ltd. (Tianjin,
China). Ultrapure water (18.2 MΩ·cm) was used throughout
the experiments.