The Visible Light Excited ESR Intensities of Various Metal Alkoxide Polymers and Their Photocatalytic Activities

Abstract

A few metal alkoxide polymers exhibit photocatalytic activities. In the present report, alkoxide polymers of various other metal elements were examined to see if such photocatalytic activities are possessed by metal alkoxide polymers in general. ESR observation has revealed that the metal alkoxide polymers also respond to visible light. The ESR response in a vacuum and in methanol vapor showed that there are two types of ESR intensity response; one type is featured with the weakened ESR signal appeared in alkoxide polymers of Cu, Mn, V, etc. and another is the strengthened ESR signal observed in alkoxide polymers of Ti, Zr, Sn, Nb, Ta. The formation of new paramagnetic species in the alkoxide polymer, when illuminated by visible light, apparently has a proportional relation to the photocatalytic activity of these metal alkoxide polymers, except for the polymers containing Ti and Zr.