Selenium and carbon nanostructures in the pores of AlPO4-5

A Tight Binding Grand Canonical Monte Carlo (TB-GCMC) simulation of the adsorption of selenium and carbon in ALPO(4)-5 zeolite is presented. We show that the structure of confined Se varies from a stretched chain to a piling of Se-5 rings, with intermediate structures combining chains and rings, while that for carbon reveals the mechanism for producing ultra small nanotubes. In the case of selenium, the ring structures are favored at low temperature and high pressures while chains are stable at higher temperatures and lower pressures. The diversity of carbon bonding allows to form chains, in-chain loops that transform into aromatic clusters and eventually tubes. These results are in qualitative agreement with recent experimental results.