Photocatalysis over Clay Supports

Abstract

Clay Minerals can be used in photocatalysis (i) to support heterogeneous redox catalysts, including metals, oxides and sulphides (ii) to anchor, by covalent linkage, homogeneous redox catalysts, and (iii) to intercalate photocatalytic transition metal complexes. The photocatalytic reaction can be performed either at the solid-solution interface in aqueous clay suspensions or at the solid-gas interface on clay powders or clay films. The influence of the clay microstructure on the distribution of molecular species in the reaction medium is of primary importance for the efficiency of the process. The reaction rate can be either considerably enhanced or totally depressed. The examples which are treated include the photo-oxidation of water, the photoreduction of water, the photocleavage of water, and the photoreduction of carbon dioxide by hydrogen (reverse water gas shift reaction).