光电流
异质结
化学
分解水
光电子学
电极
载流子
半导体
光电化学
光催化
电化学
材料科学
催化作用
物理化学
生物化学
作者
Ze Wang,Xingming Ning,Yanjun Feng,Rongfang Zhang,Yaorong He,Huihuan Zhao,Jing Chen,Peiyao Du,Xiaoquan Lu
标识
DOI:10.1021/acs.analchem.2c01607
摘要
Photoelectrochemical (PEC) water splitting technology is a promising strategy toward producing sustainable hydrogen fuel. However, it is an essential bottleneck to reduce severe charge recombination for the improvement of PEC performance. Construction of heterojunction systems, such as Z-scheme and type II heterojunctions, could efficiently boost charge separation, whereas the mechanism of charge separation is still ambiguous. We describe herein a charge transfer system designed with Bi2WO6/Bi2S3 (BWO/BS) as a prototype. In this system, Au nanoparticles act as charge relays to engineer a charge transfer pathway, and the obtained BWO/Au/BS photoanode achieves a remarkable photocurrent density of 0.094 mA cm-2 at 1.23 V versus reversible hydrogen electrode (vs RHE), over approximately 1.2 and 2.3 times larger than those of BWO/BS/Au and BWO, exhibiting long-term photostability. More importantly, scanning photoelectrochemical microscopy (SPECM) and intensity-modulated photocurrent spectroscopy (IMPS) studies are performed to in situ-capture the photogenerated hole during the PEC process. Operando analysis reveals that the Z-scheme BWO/Au/BS system (1.33 × 10-2 cm s-1) exhibits higher charge transfer kinetics compared to the type II BWO/BS/Au heterostructure (0.85 × 10-2 cm s-1) while efficiently suppressing charge recombination for optimized PEC activity. Note that this smart strategy can also be extended to other semiconductor-based photoanodes such as BiVO4. Our study offers an effective pathway for the rational design of highly efficient charge separation for solar conversion based on water splitting.
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