A new way for preparation of microporous silica containing metal nanoparticles inside pores is described. Special amphiphilic block copolymers, polybutadiene-b-poly(ethylene oxides), are used in a first step as nanoreactors for the preparation of metal nanoparticles inside their micelle cores and then as templates where the micelles act as porogens. The final product after calcination of the polymer is silica where catalytically interesting nanoparticles with controlled size, shape, and distribution are located on the pore walls. Control for nanoparticle growth and location is provided by the reduction conditions.