The effect of synthesis temperature on the particle size of nano-ZIF-8

• High synthesis temperatures in methanol lead to smaller ZIF-8 nanoparticles.
• Smaller ZIF-8 particles have larger external surface areas as determined by ASAP.
• ZIF-8 nanoparticles show increased catalytic activity compared to commercial ZIF-8.
• Increased catalytic activity due to larger external surface of ZIF-8 nanoparticles.

The particle size and size distribution of Zeolitic Imidazole Framework-8 (ZIF-8) nanoparticles are influenced by the synthesis temperature during isothermal mixing reactions in methanol. As the synthesis temperature is increased from −15 °C to 60 °C, the average nanoparticle size decreased from 78 nm to 26 nm, with a simultaneous narrowing of the particle size distribution. Adsorption studies showed an increase in the external surface area of the nanoparticles from 220 m2 g−1 till 336 m2 g−1 as the particle size decreases from 78 nm till 26 nm. The increased external surface area of ZIF-8 nanoparticles (nZIF-8) led to a significantly higher catalytic activity when compared to the catalytic activity of commercially available ZIF-8 micro-particles in a Knoevenagel condensation test reaction.

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