The reduction of Pt(IV) with activated carbon fibers-An XPS study

Activated carbon fiber is an effective reducing agent for many high oxidation state ions. The reduction-adsorption capacity for Pt(IV) of activated carbon fibers derived from viscose rayon, sisal, and pitch were studied by chemical analysis of the reaction solutions and XPS study of the deposited platinum. The reduction-adsorption capacity of the viscose-based fibers was found to be the highest. The reduction-adsorption capacity of the fibers increased with the time of activation. Significant reduction capacity was found on the viscose-based fiber even without activation. Under the acidic reaction condition, the deposited platinum was mainly in the elemental state. In the alkaline condition, the hydrolysis of Pt(IV) ions leads to the formation of PtO, which was not further reduced at room temperature. Heating of the specimen to 400 °C or above in vacuum converted the platinum to the elemental state.