Synergetic Effect of Conjugated Ni(OH)2/IrO2 Cocatalyst on Titanium-Doped Hematite Photoanode for Solar Water Splitting

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• 作者：Zhiliang Wang ; Guiji Liu ; Chunmei Ding ; Zheng Chen ; Fuxiang Zhang ; Jingying Shi ; Can Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 27, 2015
• 年：2015
• 卷：119
• 期：34
• 页码：19607-19612
• 全文大小：470K
• ISSN：1932-7455

文摘

Hematite is a promising photoanode material for renewable solar fuel production via photoelectrochemical (PEC) water splitting. However, the fast electron鈥揾ole recombination and sluggish surface reaction retard it from getting satisfied performance. Herein, hematite nanorod arrays doped with titanium (Ti鈥揊e₂O₃) on the surface were prepared by a solution-based process. Because of one-dimension anisotropy and improved charge transfer property, the photocurrent density is doubled compared to pure Fe₂O₃ at 1.50 V vs RHE under simulated sunlight (AM 1.5 G) irradiation. Loading conjugated Ni(OH)₂/IrO₂ cocatalyst further leads to about 200 mV negative shift of the onset potential and dramatic increase of the applied bias photon-to-current efficiency (ABPE). We find that Ni(OH)₂ can efficiently capture the photogenerated holes from hematite as a hole-storage layer (HSL) to improve the charge transfer process across the interface of hematite and IrO₂ electrocatalyst. Furthermore, the stored photogenerated holes in Ni(OH)₂ can be utilized by IrO₂ for water oxidation more facilely. This synergetic effect along with the efficient surface doping are proposed to be responsible for the enhanced performance.