Preparation Of Ce-modified Layered Titanates And Their Photocatalytic Reactivities

This thesis mainly includes two aspects, both of which study the preparation and photocatalytic performance of the Ce-modified layered titanate (CeTO).The first part is the preparation of CeTO via a hybrid method based on ion-exchange and thermal treatment. The impacts of pH value, cerium ion intercalation dosage and calcinaton treatment on the products were studied. The interlayer shrinkage, lattice cell contraction and lattice dislocations occur during the ion-exchange. The intercalated cerium ions were suggested as [CeO]2+ in the titanate, while thermal treatment seems promoting the recovering of some Ce3+ions. In addition, calcination treatment reduces the lattice dislocations from the ion-exchange via lattice restructuration, so the photocatalytic reactivities were enhanced after calcinaton treatment. It is lattice dislocation more than the chemical valence of cerium plays an important role in determining the photocatalytic reactivity of CeTOs.The second part of the thesis is the preparation of cerium doped sodium titanates with solid-state reaction and polymeric complex method. The as-prepared products are identified as a hexatitanate-like phase of Na4Ce3Ti6O20.The photocatalytic reactivities of the products are significantly lower than that of CeTOs prepared in the first part. It seems that the existence form of cerium ion in the titanates plays a very important role in determining the photocatalytic reactivity of Ce-modified titanate. Cerium ion intercalated into the interlayer but not doped into the host layer seems better for the separation of photogenerated electrons and holes. The BET surface area of the samples is another important factor which can influence photocatalytic reactivity.