ITO regulated high-performance n-Si/ITO/α-Fe2O3 Z-scheme heterostructure towards photoelectrochemical water splitting

Publication date: January 2020Source: Journal of Catalysis, Volume 381Author(s): Deqiang Feng, Jiangtao Qu, Rui Zhang, Xingjun Sun, Lingcheng Zheng, Hui Liu, Xinghua Zhang, Zunming Lu, Feng Lu, Weihua Wang, Hong Dong, Yahui Cheng, Hui Liu, Rongkun ZhengAbstractThe deficiencies in the separating photogenerated electrons/holes in the bulk and driving them across the interface of semiconductor/electrolyte are the major issues that limit the photoelectrochemical (PEC) performance of hematite (α-Fe2O3) photoelectrodes. In this work, a Z-scheme planar heterostructure of n-Si and α-Fe2O3 was designed and constructed by a facial ion-beam assisted deposition technique with the best match of the optical absorption depth, the film thickness and the space charge region thickness. A thin ITO layer (~10 nm) was sandwiched in-between in order to achieve the optimal carrier separation capacity, and the IrOx cocatalysts were introduced to improve the surface reaction kinetics. The results demonstrate a significant improvement of α-Fe2O3 PEC performance: a photocurrent density was improved to 1.987 mA cm−2 (1.23 V vs. RHE), ~100 times larger than that of bare α-Fe2O3, whereas the onset potential was dropped by 0.57 V over unmodified α-Fe2O3, due to the enhanced photovoltage by n-Si and the improved surface reaction kinetics. This work advances planar α-Fe2O3-based photocatalytic cells to a new performance record for water splitting.Graphical abstract

Source: Journal of Catalysis - December 14, 2019 Category: Chemistry Source Type: research