Cobalt hydroxide colloidal particles precipitation on nanoclay layers for the formation of novel nanocomposites of carbon nanotubes/nanoclay

Here we demonstrated the formation of Co(OH)2 colloidal particles on the surface of nanoclay layers with pH-controlled ion precipitation. The brucite-like phase of Co(OH)2 colloidal particles obtained exhibited a tendency for irregular growth with increasing pH. The precipitation of Co(OH)2 colloidal particles on the nanoclay surface led to the formation of a weakly ordered layered structure in the nanoclay as evidenced by the change of (0 0 1) reflections in the nanoclay structure. Two processes, physical adsorption and chemical adsorption, should be involved in the precipitation of Co(OH)2 particles on the nanoclay surface. The catalysis of the produced Co(OH)2–nanoclay hybrid was proved by the growth of CNTs with chemical vapor deposition. Under the pH value of 9.5, the resulting CNTs created a network-like structure connecting the nanoclay flakes while the nanoclay structure displayed signs of degradation after the growth of CNTs within its interlayer space. The novel CNTs–nanoclay composite structure holds high potentials for application as advanced polymer reinforcements.