Introduction of a pore connection network into mesoporous TiO₂ films to enhance CO gas sensitivity

In thiswork, ordered mesoporous TiO₂ films with interior pore connections were fabricated. To introduce the interior pore connections, the grain growth of TiO₂ on the pore wall structure was controlled by increasing the annealing time. In the annealing process, the growth of TiO₂ grains was enhanced, and interior pores were connected by a meso-channel formed during the growth of TiO₂ grains. As a result, with increasing annealing time, the specific surface area of the mesoporous TiO₂ films increased by a factor of 3, although the porosity decreased. When the ordered mesoporous TiO₂ film with enhanced pore connectivity was applied in a CO gas sensor, the gas sensitivity increased by a factor of almost 20 due to the enhanced pore connectivity resulting from controlled annealing time. The introduction of pore connectivity in a closed pore structure may be an advantageous method in various fields where a large surface area is required for nanoporous structured materials.