Preparation of Pt/Ti Electrodes Preferred Growth along the [111] Direction and Its Electrocatalytic Activity for Chlorine Evolution

Abstract

To solve the short service life of dimensionally stable anode (DSA) and the high dosage of Pt electrode in the process of low concentration sodium chloride electrolysis, the Pt/Ti electrode preferred growth along the [111] direction was prepared by magnetron sputtering. The electrode surface of the magnetron sputtering Pt was uniform with particle size of 10 nm. The characteristic peaks of Ti were not found in the XPS spectrum, which showed that the Ti matrix was completely covered by Pt. Electrochemical cyclic voltammetry (CV) results showed that the electrochemical area of the magnetron sputtering Pt was the smallest (1.08 cm), which was close to the apparent surface area of the electrode. In addition, the electrical amperage ratio of the oxygen adsorption area to the hydrogen adsorption area was only 0.83 calculated from the CV diagram. So it can be predicted that the oxygen adsorption capacity on the magnetron sputtering Pt is very poor and not prone to the oxygen evolution reaction. When the electrode potential was 1.6 V, the chlorine evolution reaction current of the magnetron sputtering Pt was 0.085 A/cm in the unit electrochemical area, which was 3.27 and 49.0 times that of the electro-deposition Pt and thermal decomposition Pt, respectively. It showed that the magnetron sputtering Pt had a high activity of chlorine evolution in the unite active site. It may be related to the special morphology of its surface (111) crystal surface. On the basis of the 第 5期 朱玉婵, 等: 沿[111]方向择优生长 Pt/Ti电极制备及析氯电催化活性 511 above, the Tafel slope of the magnetron sputtering Pt was 44.3 mV/dec. The mechanism of chlorine evolution reaction was in accordance with the mechanism of Volmer-Heyrovsky, and the rate controlling step was the electrochemical desorption step.