通过热力学计算修正的 M nSO4‐SO2－4‐H2 O镀液体系平衡电势 E0‐pH图，明确了363K和 M n2＋浓度0．2mol · dm －3时M nO2物相结构材料阳极电沉积有效pH值范围，通过对氧化物结构表征及电化学性能测试获得了pH值的影响规律。结果表明：pH值在0．33～3．4时，随着pH值增大，有利于MnO2物相结构Mn‐Mo氧化物的有效析出，但pH值增大虽可提高阳极电沉积效率，却造成镀层质量变差，电催化性能明显劣化，镀液pH＝0．5时获得的Mn‐Mo氧化物具有优异的镀层质量和高的电催化性能。原因分析表明，该现象主要与氧化物制备过程中析氧反应的竞争密切相关：pH值较小时，竞争析氧反应造成固液界面搅动，抑制氧化物枝晶生长，同时使扩散层减薄，促进氧化物在电极微观表面各处更多形核，细化晶粒，从而提高氧化物的电催化性能。
By correction to the thermodynamic calculation based on E0‐pH diagram of MnSO4‐SO2 -4 ‐H2 O plating system ,effective pH value range for anodic electrodeposition of M nO 2 phase structure materials got clear ,at 363K ,with Mn2+ concentration 0 .2mol · dm -3 .The influence law of the pH values was also obtained based on the characterization of the oxide structure and test of its electro‐chemical performance .The results show that pH value in the 0 .33‐3 .4 range ,with its increase and accordingly the conducive to the effective deposition of MnO2 type Mn‐Mo oxide .However ,although with pH value increasing ,deposition efficiency improves ,the coating quality gets degraded ,especially making the electrocatalytic performance of the oxide obviously deteriorated .It also shows that with pH value of plating solution 0 .5 ,obtained Mn‐Mo oxide has excellent coating quality and high electro‐catalytic activity .The reason is closely related to competition in oxygen evolution reaction during the preparation of the oxide .When pH value is small ,oxygen evolution reaction competition causes the solid‐liquid interface stirring ,the dendritic grow th of oxide gets inhabited and the diffusion layer gets thinning ,w hich promotes the nucleation of oxide on the electrode micro‐surface and makes grain re‐fined ,so as to improves the electrocatalytic performance of oxide .
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