Fabrication of an Efficient BiVO4-TiO2 Heterojunction Photoanode for Photoelectrochemical Water Oxidation
Fabrication of an Efficient BiVO4-TiO2 Heterojunction Photoanode for Photoelectrochemical Water Oxidation
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DOI：
10.1021/acsami.6b05489
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发表时间：
2016-08-10
影响因子：
9.5
通讯作者：
Wu, Jih-Jen
中科院分区：
文献类型：
--
作者：
Cheng, Bo-Yan;Yang, Jih-Sheng;Wu, Jih-Jen
本工作在掺氟氧化锡(FTO)衬底上制备了一种简单的平面BiVO4/TiO2异质结光阳极，用于光电化学(PEC)水氧化。表面光电压、光电流暂态行为和空穴清除剂辅助的PEC性能测试表明，与BiVO4/FTO光阳极相比，电荷分离效率有所提高。这种改善是由于形成了交错的BiVO4/TiO2异质结。但BiVO4/TiO2/FTO光阳极的光电流密度仅在可逆氢电极>；1.2V时高于BiVO4/FTO光阳极，而BiVO4/TiO2/FTO光阳极的捕光效率与BiVO4相当。空穴清除剂辅助的PEC测量表明，BiVO4/TiO2/FTO光阳极的空穴注入效率低于BiVO4/FTO裸电极的析氧效率。结果表明，BiVO4薄膜在不同的衬底上沉积时，其表面性质发生了变化。在此基础上，进一步在BiVO4/TiO2/FTO光阳极表面沉积了Co-PI催化剂，以提高空穴注入效率。与裸BiVO4/FTO光阳极相比，Co-PI/BiVO4/Ti02/FTO光阳极的光电流密度和稳定性显著提高。
In this work, a simple planar BiVO4/TiO2 heterojunction photoanode was prepared on a fluorine-doped tin oxide (FTO) substrate for photoelectrochemical (PEC) water oxidation. The measurements of surface photovoltage, photocurrent transient behavior, and hole-scavenger-assisted PEC performance indicate that charge separation efficiency is improved compared to that of the BiVO4/FTO photoanode. This improvement is caused by the formation of the staggered BiVO4/TiO2 heterojunction. However, the photocurrent densities of the BiVO4/TiO2/FTO photoanode are higher than those of the BiVO4/FTO one only at potentials >1.2 V vs reversible hydrogen electrode, although the two BiVO4 layers with comparable light harvesting efficiencies were prepared by the same method. The hole-scavenger-assisted PEC measurements reveal that the hole injection efficiency of the BiVO4/TiO2/FTO photoanode is inferior to that of the bare BiVO4/FTO anode for oxygen evolution. It shows that the surface property of the BiVO4 layers is altered as they are deposited on different substrates. On the basis of these characterizations, the cocatalyst cobalt phosphate (Co-Pi) was further deposited on the surface of BiVO4/TiO2/FTO photoanode to improve the hole injection efficiency. Subsequently, the photocurrent density and stability of the Co-Pi/BiVO4/TiO2/FTO photoanode were significantly improved compared to those of the bare BiVO4/FTO photoanode.