The mechanochemical preparation of Zn-MOF-74 and ZIF-8 followed the procedures established by Julien et al. and Tanaka et al. , respectively. For the synthesis leading to Zn-MOF-74, 6.67 mmol of zinc oxide (543 mg), 3.33 mmol of 2,5-dihydroxyterephthalic acid (H4dhta; 660 mg), and 0.75 mL of water were milled in a 15 mL poly(methyl)methacrylate (PMMA) jar, with two 7 mm diameter stainless steel balls for 90 minutes at 30 Hz. For the synthesis of ZIF-8, 3.75 mmol of zinc oxide (305 mg), 7.5 mmol of 2-methylimidazole (616 mg), and 30 mol % of zinc acetate dihydrate (247 mg) were added to an in-house made Teflon milling container, with two 7 mm diameter zirconia balls. In a Retsch MM400 mixer mill, the milling container was shaken at 30 Hz for 2 hours.