A Bicomponent TiO₂/SnO₂ Particulate Film for Photocatalysis

Plasma-enhanced chemical vapor deposition (PECVD) was used in the preparation of a series of bicomponent TiO 2 /SnO 2 particulate films. The photocatalytic activities of the films are evaluated by photodegradation of phenol in solution. When both the TiO 2 and SnO 2 components of the bicomponent TiO 2 /SnO 2 catalysts are accessible to reactants at the catalyst surface, photocatalytic degradation efficiencies are improved as compared to those obtained with TiO 2 films. When this condition prevails, the two components are believed to act in a cooperative manner by increasing the degree of charge carrier separation sufficient to reduce recombination, while simultaneously allowing sufficient time for photoelectrons and photoholes on the catalyst surface to form reaction intermediates (for example, the superoxide radical ion, O 2 ·-, formed by reaction of O 2 with photoelectrons, and the phenol radical, formed by reaction of phenol with photoholes or OH · radicals) which cooperatively participate in later stages of the degradation process.