关键词: 热分解, 二元氧化物, 析氧反应, 电化学性能

Abstract: Binary metal mixed oxides of Co and Cr with nominal compositional formulas, Co_xCr_1-xO_3/2 (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0), were obtained by thermal decomposition method. The morphologies, crystal forms and valence states of the catalyst powders were analyzed by SEM, XRD and XPS, respectively. And the electrochemical properties, overpotentials and stabilities of Co_xCr_1-xO_3/2 electrodes for oxygen evolution reaction (OER) in an alkaline solution were evaluated by linear sweep voltammetry (LSV), staircase voltammetry and chronoamperometry, respectively. The results indicated that the mixtures of Co₃O₄ and eskolaite-Cr₂O₃ formed solid solutions of Co_xCr_1-xO_3/2. When x=0.2, the electrocatalytic performance of Co_0.2Cr_0.8O_3/2 catalyst was better than those of Co₃O₄ and Cr₂O₃. At high potential region (1.0 V vs. Ag/AgCl), the current density of Co_0.2Cr_0.8O_3/2 catalyst was 3.75 times higher than that of Co₃O₄ and 15.2 times higher than that of Cr₂O₃. Furthermore, the overpotential of Co_0.2Cr_0.8O_3/2 catalyst (η = 0.0703 V at a current density of 1×10^-3 A·cm^-2) was much lower than those of Co₃O₄ (η = 0.6109 V) and Cr₂O₃ (η = 0.4350 V), showing the best electrocatalytic property. In addition, the Co_0.2Cr_0.8O_3/2 catalyst had good stability in strong alkaline solution (pH = 13) during OER process.

Key words: thermal decomposition, binary oxides, oxygen evolution reaction, electrochemical performance