Synthesis of ZIF-7 nanosheets. First, ZIF-7-I nanoparticles were prepared by adding DMF (250 mL, 3.25 mol) to Zn(NO3)•6H2O (755 mg, 2.54 mmol) and benzimidazole (1.92 g, 16.28 mmol). This mixture was left at room temperature for 72 h, stirring for the first hour only. The precipitate was then collected by centrifugation (12,000 rpm for 1 h). Particles were purified by thoroughly washing via redispersion in methanol then centrifugation (12,000 rpm for 1 h). This wash-centrifugation cycle was repeated three times before drying at 50 °C for 18 h in a vacuum oven. The particles were further dried at 120 °C for 48 h in a vacuum oven. ZIF-7-I was redispersed in distilled water (0.5 wt%) and refluxed at 100 °C for 24 h. The turbid mixture was washed with distilled water once and methanol three times by redispersion and centrifuging (12,000 rpm for 1 h). The white solid was then dried at 50 °C overnight to obtain ZIF-7-III. Finally, ZIF-7-III (80 mg) was ultrasonicated in a 1:1 v/v methanol/n-propanol mixture (120 mL) at 80 KHz for 2 h to access nanosheets. After centrifugation at 500 rpm for 5 min, the resulting supernatant containing the nanosheets was then centrifuged at 12,000 rpm for 1 h. nanoparticles were then collected by centrifugation (12,000 rpm for 1 h). Particles were purified by thoroughly washing via redispersion in methanol followed by centrifugation (12,000 rpm for 1 h). This wash-centrifugation cycle was repeated three times before drying at 50 °C for 18 h in a vacuum oven. The particles were further dried at 120 °C for 48 h in a vacuum oven. ZIF-7-NH2-I was redispersed in distilled water at a concentration of 0.5 wt % and refluxed at 100 °C for 1 week. The turbid mixture was washed with distilled water once and methanol three times, and then dried at 50 °C overnight to obtain ZIF-7-NH2-III. 80 mg ZIF-7-NH2-III was ultrasonicated in 1:1 v/v methanol/n-propanol (120 mL) at 80 KHz for 2 h to access nanosheets. After centrifugation at 500 rpm for 5 min, the resulting supernatant containing the nanosheets was then centrifuged at 12,000 rpm for 1 h.