Unravelling charge separation via surface built-in electric fields within single particulate photocatalysts
Unravelling charge separation via surface built-in electric fields within single particulate photocatalysts
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通过单颗粒光催化剂内的表面内置电场解开电荷分离
DOI：
10.1039/c6fd00214e
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发表时间：
2017-06-01
影响因子：
3.4
通讯作者：
Li, Can
中科院分区：
文献类型：
--
作者：
Chen, Ruotian;Zhu, Jian;Li, Can
利用开尔文探针力显微镜(KPFM)和空间分辨表面光伏(SRSPV)技术研究了单颗粒光催化剂的内建电场和表面光生电荷分布。光生空穴和分布在整个颗粒表面的电子分别成像在n型BiVO4和p型Cu2O颗粒上。结果表明，表面空间电荷区(SCR)的内建电场决定了电荷的分离/转移过程，并允许一种光生载流子漂移到表面，同时将另一种光生载流子保持在体中。这些结果强调了SCR在颗粒光催化剂中体相与表面之间的单向电荷传输中所起的作用，这可能是导致太阳能转换效率低的关键原因。
Kelvin Probe Force Microscopy (KPFM) and spatially resolved surface photovoltage (SRSPV) techniques were employed to reveal built-in electric fields and surface photogenerated charge distribution on single particulate photocatalysts. The photogenerated holes and electrons spread over the whole surface of the particulate photocatalyst are imaged on n-type BiVO4 and p-type Cu2O single particles, respectively. It is demonstrated that the built-in electric field in the surface Space Charge Region (SCR) dictates the charge separation/transfer processes and allows the drift of one kind of the photogenerated carriers to the surface, while holding another kind of the carriers in the bulk. The results emphasize the role of the SCR played in the unidirectional charge transport between the bulk and surface in the particulate photocatalyst, which may be the crucial reason for low solar energy conversion efficiency.