Effects of selective leaching of bismuth oxide sheets in triple-layered Aurivillius phases on their photocatalytic activities

The photocatalytic activities of triple-layered Aurivillius phases, Bi2A′NaNb3O12 (A′=Sr, Ca) and Bi2CaNaTa3O12, and of protonated forms prepared from these Aurivillius phases through selective leaching of bismuth oxide sheets were investigated. UV–Vis diffuse reflectance spectra showed blue shifts of the adsorption edges upon selective leaching. Although none of the triple-layered Aurivillius phases were active for photocatalytic H2 evolution from a 20 vol% ethanol solution, all the corresponding protonated forms showed photocatalytic activities for H2 evolution. The effects of the changes in electronic structures and interlayer surface creation on photocatalytic activities are discussed.