Effect of surface photoreactions on the photocoloration of a wide band gap metal oxide: Probing whether surface reactions are photocatalytic

The study was aimed at examining the effect(s) of surface photochemical reactions involving H(sub 2), O(sub 2), NH(sub 3), and CO(sub 2) on the photocoloration of ZrO(sub 2) in particular, and metal oxides in general. The effect of a nonphotocatalytic reaction occurring on the surface of an irradiated wide band gap metal oxide is seen as the influence of photosimulated adsorption on the photocoloration of the metal oxide specimen.