Back Electron Transfer at TiO(2)Nanotube Photoanodes in the Presence of a H2O2 Hole Scavenger
Back Electron Transfer at TiO(2)Nanotube Photoanodes in the Presence of a H2O2 Hole Scavenger
复制标题
H2O2 空穴清除剂存在下 TiO(2) 纳米管光电阳极的反向电子转移
DOI：
10.1021/acsami.7b09827
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发表时间：
2017
影响因子：
9.5
通讯作者：
Zou Zhigang
中科院分区：
文献类型：
--
作者：
Zhu Heng;Yan Shicheng;Li Zhaosheng;Zou Zhigang
添加电荷清除剂是一种有效的方法，它通常比水更不稳定，可以量化在水裂解反应的电荷分离、转移和注入过程中光电极的量子效率损失。在这里，我们检测到，在使用过氧化氢（H2 O2）作为空穴清除剂后，TiO 2纳米管光阳极在碱性电解质中的饱和光电流下降了近40%，而在酸性电解质中的饱和光电流差异可以忽略不计。我们发现，光电子被捕获在表面态的TiO 2与几乎相同的电子存储容量在很宽的pH值范围内从1.0到13.6。然而，动力学的逆反应，H2O2还原被捕获在表面状态的光电子，是约10倍，在碱性电解质比在酸性电解质。结果表明，pH依赖的H2O2还原动力学差异对饱和光电流产生了负面影响.我们的研究结果为理解背电子转移对表面态和电荷清除剂电化学行为的影响提供了新的视角。
Adding charge scavengers, which usually are more unstable than water, is an effective method to quantify the quantum efficiency loss of photoelectrode during the charge separation, transfer, and injection processes of the water splitting reaction. Here, we detected, on TiO2nanotube photoanodes after using hydrogen peroxide (H2O2) as a hole scavenger, a nearly 40% saturated photocurrent decrease in alkaline electrolyte and a negligible saturated photocurrent difference in acid electrolyte. We found that the photoelectrons were trapped in the surface states of TiO2with nearly the same storage capacity of electrons in a wide range of pH values from 1.0 to 13.6. However, kinetics of a back reaction, H2O2reduction by the photoelectrons trapped in surface states, is about 10 times higher for that in alkaline electrolyte than in acid electrolyte. As a result, the pH-dependent kinetic difference in H2O2reduction induced the negative effects on the saturated photocurrent. Our results offer a new insight into understanding the effects of back electron transfer on electrochemical behaviors of surface states and charge scavengers.