Plasma Treating Mixed Metal Oxides to Improve Oxidative Performance via Defect Generation.

The generation of structural defects in metal oxide catalysts offers a potential pathway to improve performance. Herein, we investigated the effect of thermal hydrogenation and low-temperature plasma treatments on mixed SiO/TiO materials. Hydrogenation at 500 °C resulted in the reduction of the material to produce Ti in the bulk TiO. In contrast, low temperature plasma treatment for 10 or 20 min generated surface Ti species via the removal of oxygen on both the neat and hydrogenated material. Assessing the photocatalytic activity of the materials demonstrated a 40-130% increase in the rate of formic acid oxidation after plasma treatment. A strong relationship between the Ti content and catalyst activity was established, although a change in the Si-Ti interaction after plasma treating of the neat SiO/TiO material was found to limit performance, and suggests that performance is not determined solely by the presence of Ti.