1 Supporting information Ordered mesoporous silica-(ZIF-8) core-shell spheres Sara Sorribas, Beatriz Zornoza, Carlos Téllez,* and Joaquín Coronas Chemical and Environmental Engineering Department and Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza, Spain *Corresponding author: ctellez@unizar.es Experimental Chemicals: Cetyltrimethylammonium bromide (CTABr, >98%, Sigma–Aldrich), sodium metasilicate (Na 2 SiO 3 , Sigma–Aldrich), and ethylacetate (CH 3 COOC 2 H 5 , 99.9% Sigma–Aldrich) were used to synthesize silica spheres. Zinc nitrate hexahydrate (ZnNO 3 ·6H 2 O, >98%, Sigma-Aldrich) was used as Zn source and 2-methylimidazole (C 4 H 6 N 2 , >99%, Sigma-Aldrich) was used as ligand for the synthesis of ZIF-8. Methanol (99.99%) was obtained from Sigma-Aldrich. Mesoporous silica spheres (MSSs): The molar composition used for the preparation of MSSs was 1.5Na 2 SiO 3 :1CTABr:361H 2 O:7.4CH 3 COOC 2 H 5 . For this, 3.92 g CTABr and 2 g of Na 2 SiO 3 were dissolved in 70 mL of water. Then, 8 mL of ethylacetate was added under stirring for 30 s. After mixing of the reactants, the solution was kept in a closed polypropylene flask at room temperature for 5 h, and then maintained at 90 ºC for 50 h. The product obtained was filtered in distilled water and ethanol, and calcined at 600 ºC for 8 h with a heating rate of 0.5 K/min to remove the surfactant. At these conditions, MCM-41 pores of about 2.7 nm with stable silica walls between the micelles, as well as non-MCM-41 pores of about 15 nm with unstable or even missing walls due to removal of surfactant micelles were created inside the silica spheres. Electronic Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2012