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

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 NO 2 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 m 2 /g. When exposed to NO 2 gas, NO 2 molecules tend to physisorb on the nanotube surface via the nonbonding p y orbital of the oxygen atoms. In contrast nanoribbons have much smaller active surface areas (∼30 m 2 /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 the removal and catalysis of nitrogen oxides in future.