Photocatalytic and Photoelectrocatalytic Degradation of the Explosive RDX by TiO_2 Thin Films Prepared by CVD and Anodic Oxidation of Ti

摘要

Two kinds of TiO_2 films prepared by CVD and by anodization of titanium mesh are compared for the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation of RDX aqueous solutions illuminated under a 200W UV light. The PC activity of anodically formed TiO_2 is lower than that with CVD-produced TiO_2. The PC efficiencies of degradation of RDX with both anodized and CVD films are improved by applying a potential of 1V versus saturated calomel electrode (SCE), with up to 95% of RDX being destroyed in two hours by a CVD-produced TiO_2 film, and 81% by anodized TiO_2. Chemical analysis shows that during RDX degradation, nitrite is the first mineralized product which is further oxidized to nitrate.