Deactivation Mechanism of Pt Anode in the Process of Electroxidation of p-Chlorophenol
对氯苯酚电氧化过程中Pt电极的失活机制

Deactivation of Pt electrode in the process of electroxidation of p-chlorophenol (p-CP) was investigated using linear sweep voltammetry, LC/MS and spectrum analysis techniques. The experiment results indicated that Pt would lose its electro-catalytic activity soon because polymer formed at the electrode surface. The in-site IR spectra of Pt showed two weak absorption bands appeared at 1 200 and 1 800 cm-1 during the oxidation of p-CP, which are characteristics of aromatic ether and carbonyl group, respectively. Increasing initial concentration of p-CP and pH value of solution would accelerate the deactivation speed of Pt. Acetonitrile lixivium for deactivated Pt was analyzed by LC/MS, and it was found that the polymers formed at the surface of Pt were some mixed compounds. The mechanism of polymerization includes the following ways: coupling reaction of organic radical each other; substituting reaction of organic radical with p-CP (or intermediates or small polymers).