Three types of Ti-O-compound-based nanobelts (Na2Ti3O7, H2Ti3O7, TiO2) are prepared from commercial TiO2 powders via an alkaline hydrothermal process. Nanostructured sheets based on the as-synthesized nanobelts are prepared using a paper-making process. The nanobelts are connected with hydrogen bonds or/and bridge oxygen atoms and packed together, forming a paperlike porous network structure, with an average pore size of similar to 500 nm. The electrical properties and gas sensing of the nanostructured sheets are demonstrated to display sensitivity down to sub-ppb levels. H2Ti3O7 nanobelts decorated with Ag nanoparticles have also been applied as an antibacterial agent.