Modification of the interlayer in K[Ca2Nan-3NbnO3n+1] and their photocatalytic performance for water cleavage

Layered compounds K[Ca2Nan-3NbnO3n+1] (3 less than or equal to n less than or equal to 6) were prepared by solid reaction at high temperatures, and the processes for the modification of the interlayers by protonation, intercalation and pillaring were investigated. n-hexylamine could easily be intercalated into the interlayers of H[Ca2Nan-3NbnO3n+1] and enhanced significantly the interlayer distance, which facilitated the incorporation and reaction of tetraethyl orthosilicate with n-hexylamine intercalated compounds. The analysis of XRD, TG-DTA and TEM indicated that silica-pillared layered compounds were formed and had high thermal stability. By comparing the rates of hydrogen evolution from water cleavage on various compounds, the enhancement in the activity of proton-exchanged and silica-pillared compounds was examined in the case of loading Pt. The promotion effect might be due to the adsorption and combination of Pt on the surface of compounds proton-exchanged and pillared. (C) 2001 Kluwer Academic Publishers.