Sulfonic acid groups were anchored on a silica surface through robust Si-C bonds. The successive treatment of dehydroxylated silica with benzylmagnesium chloride and H2SO4 resulted in the surface tethering of -CH2C6H4SO3H groups at a high coverage rate (0.50-CH2C6H4SO3H/nm(2)). The pore structure of the silica remained unchanged during this surface-modification process. Next, the -CH2C6H4SO3H groups on the surface were successfully used for preparing a supported catalyst for CO/ethylene copolymerization; the Si-CH2C6H4SO3H groups on the surface were reacted with [1,3-bis(di(2-methoxyphenyl)phosphino)propane]Pd-( OAc)(2) to generate dicationic palladium species, which were anchored on the silica surface through ionic interactions with the sulfonate anions generated on the surface. The supported catalyst prepared in this way exhibited a high activity (up to 43 kg/g-Pd or 0.61 kg/g-cat) with respect to CO/ethylene copolymerization. The morphology of the obtained polymer particles replicated that of the silica particles. Thus, a polymer powder that exhibited a high bulk density (0.30 g/mL) could be obtained while causing minimal reactor fouling. (C) 2015 Elsevier B.V. All rights reserved.