Cobalt nitrate hexahydrate

Cobalt nitrate hexahydrate (Co(NO₃)₂·6H₂O), cetyltrimethylammonium bromide (CTAB), potassium hydroxide (KOH) and ferric chloride hexahydrate (FeCl₃·6H₂O) were provided by Tianjin Damao Chemical Reagent corporation. Tannic acid (TA) and sodium borohydride (NaBH₄) were purchased from Aladdin. Nafion solution (5 wt%) was purchased from the Aldrich corporation. All chemicals were used directly without further purification. In addition to the above, carbon paper was purchased from the Jinglong Special Carbon Company, Beijing, China.

The materials and reagents are as follows: 2-Methylimidazole (99%, J&K, Beijing, China), thiourea (99%, J&K, Beijing, China), potassium bromide (99%, J&K, Beijing, China), zinc dihydrate acetate (99%, J&K, Beijing, China), sodium sulfate (99%, J&K, Beijing, China), disodium ethylenediaminetetraacetic acid (EDTA) (99%, J&K, Beijing, China), benzoquinone (99%, J&K, Beijing, China), methanol (≥99.7%, J&K, Beijing, China), isopropanol (99.5%, J&K, Beijing, China), Rhodamine B (96%, J&K, Beijing, China), anhydrous ethanol (≥99.7%, Fuyu chemical, Tianjin, China), cobalt nitrate hexahydrate (98%, Damao chemical reagent factory, Tianjin, China), and cadmium acetate dihydrate (99%, Thermo Fisher Scientific, Waltham, MA, USA). The ITO slides are purchased from Luoyang Guluo Glas Co., Ltd. (Luoyang, China).