A reactor and method for seeded growth of nano-products such as carbon nanotubes, wires and filaments in which selected precursors are introduced into the reactor which is heated to a temperature sufficient to induce nano-product formation from interaction between the precursor gases and a nanopore templated catalyst. The selected precursors are segregated in the reactor through a plate defining two chambers which are sealed off from each other except for a void space provided in the plate. The void space is closed off by a membrane having nanopores and a catalyst formed as a layer. Atomic transfer of material from the selected precursors to form the nano-products on the catalyst layer in the other of the chambers occurs by diffusion through the catalyst layer to form the nano-product on the other of the chambers absent a pressure drop between the two chambers.