Stabilization of Platinum-Loaded CdS Photocatalyst by Addition of EDTA

Abstract

The photocatalytic activity of platinum-loaded CdS powder in sulfite solutions declined by illumination over 200 h, and became half the initial activity at 600 h. By addition of small amount (2 mM) of ethylenediaminetetraacetic acid (EDTA) to the solution, however, the photocatalyst was guarded from deterioration. The effect of EDTA is to prevent the platinum part of photocatalyst from the impurity metal deposition by forming stable metal-EDTA complexes in the solution. The reactivities of sulfite ions, EDTA, and metal-EDTA complexes on illuminated CdS are examined electrochemically by use of CdS-sinter electrodes.