The proper band alignment of coupled semiconductor plays a key role on enhancing photocatalytic activity due to the valence and conduction difference in the interface to drive the photogenerated charge carrier separation. However, little is known about the exact band alignment of coupled semiconductors due to that most band alignments were schematic by valence of monocomponent, but not consider the interface effect of coupled semiconductors. Herein the novel synthesis strategy via in situ chemical transformation was successfully utilized to prepare BiVO₄/BiOCl {001} heterojunctions. The results of transmission electron microscopy (TEM) show that BiVO₄/BiOCl photocatalyst was made of BiOCl sheets and BiVO₄ nanoparticles. The exact band alignment was experimentally demonstrated in BiVO₄/BiOCl through X-ray photoelectron spectroscopy (XPS). The results show that the valence band difference is 0.58 eV which is a driving force valence of band holes from BiVO₄ to BiOCl by the valence band offset. While the reductive electrons were driven by conduction band difference (1.27 eV) along the opposite direction compared to the oxidative holes. The large driving force for the charge transport across the interface explains the high photocatalytic activity achieved by the BiVO₄/BiOCl.

中文翻译：

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高效的光催化活性，通过原位化学转化制备的BiVO ₄ / BiOCl {001}的能带排列

耦合半导体的正确能带对准由于界面中的价和传导差异以驱动光生电荷载流子分离，因此在增强光催化活性方面起着关键作用。但是，对耦合半导体的精确能带对准知之甚少，这是因为大多数能带对准是通过单组分的价来表示的，而不考虑耦合半导体的界面效应。本文中，通过原位化学转化的新颖合成策略被成功地用于制备BiVO ₄ / BiOCl {001}异质结。透射电子显微镜（TEM）的结果表明BiVO ₄ / BiOCl光催化剂由BiOCl片和BiVO ₄制成纳米粒子。通过X射线光电子能谱（XPS）在BiVO ₄ / BiOCl中通过实验证明了精确的能带对准。结果表明，价带差为0.58eV，这是通过价带偏移从BiVO ₄到BiOCl的带孔的驱动力价。虽然还原电子是由与氧化空穴相比相反的方向的导带差（1.27 eV）驱动的。跨界面的电荷传输的巨大驱动力说明了BiVO ₄ / BiOCl具有很高的光催化活性。