THERMAL STABILITY AND SURFACE ACTIVITY OF NANO (Ce_xTi_1-x)O₂

Today, the use of green renewable energy and its storage and conveyance are of utmost importance, placing the field at the center of technological and scientific inquiry. Of the sustainable energy carriers known to date, reduced reactive gases (i.e. H₂ or CO, or a mixture thereof) are the most promising. Such gases are produced by way of molecular gas (i.e. H₂O or CO₂) reduction/splitting. Cerium dioxide (CeO₂, ceria) is a remarkable material with a unique set of properties, such as a chemically active surface and high ionic conductivity, which allow it to play a significant role in the thermal reduction (splitting) of these gases, thereby reducing the enormous energy requirements of the process. Still, the poor thermal stability of CeO₂ hinders its ability to perform at high temperatures. To resolve this issue, the use of dopants has been suggested. In the present talk, the effect of TiO₂ on the thermal stability and surface composition and activity in the TiO₂ doped ceria will be discussed. In limited amount TiO₂ was found to act as a thermal stabilizer in ceria, thereby hindering coarsening up to 800 ^oC. Moreover, the photocatalytic properties of TiO₂ show a promising path for enhanced hydrogen production in the TiO₂-CeO₂ system.