LAUSR

Abstract PbO 2 /α-Al 2 O 3 composite electrodes were successfully synthesized using composite electrodeposition technology and applied for the electrocatalytic degradation of neutral red (NR). The effect of α-Al 2 O 3 particles on the surface morphology, structure, stability and electrochemical properties of PbO 2 /α-Al 2 O 3 composite electrodes were characterized. The results showed that the incorporation of α-Al 2 O 3 particles can fine the crystal size of lead dioxide and form compact film structure. PbO 2 /α-Al 2 O 3 composite electrodes exhibited larger electrochemical active surface area, stronger hydroxyl radical generation ability and longer service lifetime than PbO 2 electrodes. Electrochemical oxidization experiments showed that PbO 2 /α-Al 2 O 3 composite electrodes had the higher neutral red and COD removal efficiency, lower energy consumption and minimum Pb dissolution than PbO 2 electrodes. Finally, hypothetical electrocatalytic degradation pathway of neutral red on PbO 2 /α-Al 2 O 3 composite electrode was proposed, which was dominated by hydroxyl radical mediated oxidization reaction. Under reaction with hydroxyl radicals, neutral red was gradually de-functionalized and hydroxylized to form π-delocalization shrink byproducts, which were transformed to multiple organic acids and then to inorganic substances H 2 O and CO 2 ultimately.