Synthesis of Ni-ZIF-8
Ni-ZIF-8 nanoparticles were made according to the method available elsewhere44. Zn (NO3)2.6H2O (1.188 g) and Ni (NO3)2.6H2O (1.172 g) were mixed in 200 ml methanol separately and mixed with the solution of 2-methylimidazole (5.296 g) in methanol (100 ml), which was stirred for next 24 hrs at ambient conditions. Then violet color powder was washed three times with methanol and dried in a vacuum oven at 80°C.