Effect of Additives on the Photocatalytic Decomposition of Acetic Acid in TiO₂ Suspensions

Abstract

Photocatalytic decomposition of acetic acid in TiO₂ suspensions is accelerated by addition of reducible species such as Cu²⁺, Fe³⁺, CuO and MnO₂. This process is proposed to involve the capture of the electron photogenerated in the TiO₂ by these species, which suppresses the undesirable electron-hole recombination. The decomposition is retarded when less reducible species such as Ti⁴⁺ and Sn⁴⁺ are added instead. Significant enhancement of the decompositi on is observed when copper powder is added to the suspension. This process is also considered to stem from the trapping of photogeneratedelectron in the TiO₂ by copper particles.