Impact of Structure and Morphology on Gas Adsorption of Titanate-Based Nanotubes and Nanoribbons

Abstract

We report on the synthesis of titania-based nanotubes and nanoribbons prepared by hydrothermal methods, as well as evaluating their structure and adsorption properties. Nanotubes were found to be hollow scrolls with a typical outer diameter of about 10 nm, inner diameter 4−5 nm and length of several hundred nm. The nanoribbons are highly crystalline, typically 40 nm in cross-section and up to a few μm in length. All these samples were exposed to a NO2 atmosphere in order to test their adsorption properties using electron paramagnetic resonance (EPR). The nanotubes were found to have high active surface areas of about 250 m2/g. When exposed to NO2 gas, NO2 molecules tend to physisorb on the nanotube surface via the nonbonding py orbital of the oxygen atoms. In contrast nanoribbons have much smaller active surface areas (∼30 m2/g). The dominant EPR signal now comes from NO molecules adsorbed on Na+ ions. These results show that titania-based nanotubes and nanoribbons may represent an attractive option for t...