In a typical synthesis, 10 grams of semicarbazide gels from previous step were cut into the pieces and placed into 100-mL round bottom flask. In method A, 3 grams of anhydrous K2CO3 and anhydrous ethanol was put and refluxed for 24 hours. After, gel was placed into beaker and kept in 100 mL water for 20 minutes. This process repeated for 4 times. Then, gel was dried under open air for 2-3 days. In method B, gels were placed into aqueous K2CO3 solution (10% w/w) and refluxed for 2 days. Finally, gels were dialyzed against DI water several times to remove K2CO3 completely.