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本文用循环伏安、交流阻抗等电化学方法研究了Keggin型钴取代杂多阴离子PW11O39Co(Ⅱ)(H2O)5-(PW11Co)的电化学性质及其对H2O2和甲醇阳极氧化的电催化作用,提出了PW11Co作为阳极媒质可能的电催化机理.结果表明,PW11Co除了2对可逆的W—O骨架峰之外,在1.367 V/1.266 V处还有1对准可逆的Co峰,对应于Co(Ⅱ)/Co(Ⅲ)电对的氧化还原响应.该电极过程有质子参与,其交换电流密度i0为5.7×10-6A·cm-2.在酸性条件下(pH 2.5),PW11Co对H2O2的阳极氧化具有明显的电催化活性,耦合甲醇的氧化可使甲醇的氧化速率显著提高.
In this paper, the electrochemical properties of Keggin-type cobalt-substituted heteropolyanion PW11O39Co (Ⅱ) (H2O) 5- (PW11Co) and its electrocatalytic activity for H2O2 and methanol anodic oxidation were studied by cyclic voltammetry and electrochemical impedance spectroscopy. The possible electrocatalytic mechanism of PW11Co as anode is proposed. The results show that PW11Co has 1 aligned Co peak reversible at 1.367 V / 1.266 V except 2 pairs of reversible W-O framework peaks, corresponding to Co (Ⅱ) ) / Co (Ⅲ). The proton exchange rate of this electrode was 5.7 × 10-6 A · cm-2. Under acidic conditions (pH 2.5) Oxidation has obvious electrocatalytic activity, coupled with the oxidation of methanol methanol oxidation rate can be significantly improved.