An alternative approach to ascertain the rate-determining steps of TiO2 photoelectrocatalytic reaction by electrochemical impedance spectroscopy
An alternative approach to ascertain the rate-determining steps of TiO2 photoelectrocatalytic reaction by electrochemical impedance spectroscopy
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DOI：
10.1021/jp034113r
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发表时间：
2003-08-28
影响因子：
3.3
通讯作者：
Li, WZ
中科院分区：
文献类型：
--
作者：
Liu, H;Li, XZ;Li, WZ
为了确定二氧化钛光电催化(PEC)反应的速率控制步骤(RDS)，应用电化学阻抗谱(EIS)方法监测了二氧化钛电极反应体系中磺基水杨酸(SSA)溶液的PEC氧化过程。同时，首次建立了电化学阻抗谱数学模型，对PEC反应进行了理论模拟。在EIS模型的基础上，对PEC氧化过程中的三个典型反应进行了理论模拟，包括电荷转移为主的反应、电荷转移和吸附为主的反应以及吸附为主的反应。电化学阻抗谱测试结果表明，当外加偏压低于200 mV(VsSCE)时，SSA PEC降解的交流阻抗谱平面上只出现一个弧形/半圆形，而当外加偏压超过200 mV(VsSCE)时，则出现两个弧形/半圆形。实验结果与模型模拟结果吻合较好。本研究中的EIS方法为PEC氧化过程中RDS的测定提供了一种更简便的方法，有助于在实际应用中更好地控制反应。
In an attempt to ascertain the rate-determining steps (RDS) of TiO2 photoelectrocatalytic (PEC) reaction, the PEC oxidation of sulfosalicylic acid (SSA) solution in a TiO2-coated electrode reactor system was monitored by applying the electrochemical impedance spectroscopy (EIS) method. In the meantime, an EIS mathematical model was first established to theoretically simulate the PEC reaction. Based on the EIS model, the theoretical simulation indicates three typical reactions in a PEC oxidation process, which include the charge-transfer-dominated reaction, both the charge-transfer- and adsorption-dominated reaction, and the adsorption-dominated reaction. The experimental results of EIS measurement showed that there was only one arc/semicircle on the EIS plane display when the external bias applied was below 200 mV (vs SCE) in the SSA PEC degradation whereas there were two arcs/semicircles when the externally applied bias exceeded 200 mV (vs SCE). The experimental results have a good agreement with the model simulation. The EIS method in this study provides an easier way to determine the RDS in a PEC oxidation process, which would be helpful to better control the reaction in practice.