The preparation of Ag/mesoporous silica by direct silver reduction and Ag/functionalized mesoporous silica by in situ formation of adsorbed silver

Mesoporous silica (MS) with large pores and thiol functionalized mesoporous silica (TFMS) were synthesized. 29Si MAS NMR confirmed the functionalization of MPTMS on the surface of mesoporous silica. Silver nanoparticles were prepared by two methods: (1) direct reduction of Ag+ ions with NaBH4 in aqueous AgNO3 solution containing MS, (2) in situ reduction of Ag+ ions adsorbed on TFMS with NaBH4. The characteristics of products from both methods were compared using SAXRD, TEM, and N2 adsorption–desorption. Ag nanoclusters were mostly confined and dispersed in the channels of the TFMS and their sizes were under 6 nm. However, Ag nanoparticles on the MS formed outside the mesoporous channels rather than within them.