Abstract: Thermal oxidation of Pd in air was studied by thermogravimetric analysis. The composition and properties of the palladium oxide electrodes prepared at different temperatures were characterized by using XPS and electrochemical methods. It is found that the pHresponse of these electrodes depends strongly on the preparation temperature, and Pd( Ⅳ ) oxide is essential to a better pHrespone. The pH-sensing mechanism .was also discussed.

Key words: Palladium oxide electrodes, PH sensor, XPS analysis