The kinetics of the V⁵⁺/V⁴⁺ redox reaction is investigated in a three-electrode configuration on a Vulcan XC-72 modified glassy carbon rotating disk electrode at four different temperatures (25 to 40 °C, with 5 °C interval). The values of enthalpy of activation (ΔH^#) and pre-exponential factor (A_f) estimated using the Eyring equation are in the range of 0.25–0.53 eV (24–51 kJ mol⁻¹) and −1.3 to 5, respectively. The Eyring plots tend to diverge with overpotential, causing an increase in the values of the estimated ΔH^# and A_f. This is perhaps due to the retarding effect of the precipitates/adsorbates on the electrode surface. The investigation of the kinetics suggests that the V⁵⁺/V⁴⁺ redox reaction is electrocatalysed through an increase in the entropy of activation (ΔS^#).

中文翻译：

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过电位对电化学氧化还原反应活化焓和指前因子的影响

V ⁵⁺ /V ⁴⁺氧化还原反应的动力学在 Vulcan XC-72 改性玻碳旋转圆盘电极上的三电极配置中在四种不同温度（25 至 40 °C，间隔 5 °C）下进行了研究. 使用 Eyring 方程估计的活化焓 (Δ H ^# ) 和指前因子 ( A _{f ) 的值分别在 0.25-0.53 eV (24-51 kJ mol} ^-1 ) 和 -1.3 到 5的范围内. 艾林图倾向于随着过电位而发散，导致估计的 Δ H ^#和A _{f的值增加}. 这可能是由于电极表面上的沉淀物/吸附物的阻滞作用。动力学研究表明，V ⁵⁺ /V ⁴⁺氧化还原反应是通过增加活化熵（Δ S ^#）来电催化的。