Durability of Ag-TiO2 Photocatalysts Assessed for the Degradation of Dichloroacetic Acid

Abstract EN

The stability of Ag-TiO2 photocatalysts was examined for the photocatalytic degradation of dichloroacetic acid (DCA) as a function of the recycling times.

The photocatalytic activity was investigated by measuring the rate of H+ ions released during the photodegradation of DCA and confirmed by measuring the total organic carbon removal.

The photodegradation reactions were studied at pH 3 and pH 10 for a series of Ag-TiO2 photocatalysts as different with Ag loadings .

All the Ag-TiO2 and bare TiO2 photocatalysts showed a decrease in photocatalytic activity on recycling for the DCA photodegradation reaction.

The decrease in activity can be attributed to poisoning of active sites by Cl− anions formed during the photocatalytic DCA degradation.

The photocatalytic activity was, however, easily recovered by a simple washing technique.

The reversibility of the poisoning is taken as evidence to support the idea that the recycling of Ag-P25 TiO2 photocatalysts does not have a permanent negative effect on their photocatalytic performance for the degradation of DCA.

The choice of the preparation procedure for the Ag-TiO2 photocatalysts is shown to be of significant importance for the observed changes in the photocatalytic activity of the Ag-TiO2 particles.