Kim Kiwon, Yang Jiwoo, Moon Jun Hyuk
Department of Chemical and Biomolecular Engineering, Sogang University, Baekbeom-ro 35, Mapo-gu, Seoul 04107, Republic of Korea.
ACS Appl Mater Interfaces. 2020 May 13;12(19):21894-21902. doi: 10.1021/acsami.0c03958. Epub 2020 May 4.
Understanding the photogenerated charge-transport dynamics of metal oxide electrodes is the key to providing a strategy for practical improvement in the photoelectrochemical reaction activity. Here, we analyze the electron transport of a 3D bicontinuous SnO/BiVO nanostructured photoelectrode by intensity-modulated photocurrent spectroscopy. We compare this electrode with 3D WO/BiVO and planar-type bilayer SnO/BiVO electrodes. In the results, we observe an order of magnitude faster electron transport in the 3D electrodes relative to the bilayer electrode. Moreover, we observe trap-limited transport on widely applied WO/BiVO electrodes but confirm rapid trap-free transport on 3D SnO/BiVO. We also characterize the effect of electron transport on the water-splitting reaction. The electron-transport rate is directly related to the charge-separation efficiency in the water-splitting reaction. The fast transport time of the 3D SnO/BiVO leads to the achievement of a significantly higher charge separation efficiency of 94%.
理解金属氧化物电极的光生电荷传输动力学是为光化学反应活性的实际提高提供策略的关键。在此，我们通过强度调制光电流光谱分析了三维双连续SnO/BiVO纳米结构光电极的电子传输。我们将该电极与三维WO/BiVO和平面型双层SnO/BiVO电极进行了比较。结果表明，相对于双层电极，我们观察到三维电极中的电子传输速度快了一个数量级。此外，我们在广泛应用的WO/BiVO电极上观察到陷阱限制传输，但证实了三维SnO/BiVO上的快速无陷阱传输。我们还表征了电子传输对水分解反应的影响。电子传输速率与水分解反应中的电荷分离效率直接相关。三维SnO/BiVO的快速传输时间导致实现了高达94%的显著更高的电荷分离效率。
