Enhanced Charge Separation through ALD-Modified Fe2O3/Fe2TiO5 Nanorod Heterojunction for Photoelectrochemical Water Oxidation
Enhanced Charge Separation through ALD-Modified Fe2O3/Fe2TiO5 Nanorod Heterojunction for Photoelectrochemical Water Oxidation
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通过 ALD 修饰的 Fe2O3/Fe2TiO5 纳米棒异质结增强电荷分离用于光电化学水氧化
DOI：
10.1002/smll.201600940
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发表时间：
2016
期刊：
影响因子：
13.3
通讯作者：
Gong Jinlong
中科院分区：
文献类型：
--
作者：
Li Chengcheng;Wang Tuo;Luo Zhibin;Liu Shanshan;Gong Jinlong
赤铁矿具有用于太阳能水分解的差的电荷传输和分离性质。本文介绍了一种改进电荷分离的三维Fe 2 O3/Fe 2 TiO 5异质结光阳极的设计和制备，通过一种简单的水热方法，然后原子层沉积和空气退火。高度结晶的Fe 2 TiO 5相与底层Fe 2 O3核心形成明显的界面，其中4 nm的Fe 2 TiO 5覆盖层导致最佳的光电化学性能。Fe 2 O3和Fe 2 TiO 5之间有利的能带偏移在Fe 2 O3/Fe 2 TiO 5界面处建立了II型异质结，这有效地驱动了电子-空穴分离。Fe 2 O3/Fe 2 TiO 5复合电极在1.23 V下的光电流比可逆氢电极（RHE）在模拟1太阳光照（100 mW cm−2）下的光电流显著提高，为1.63 mA cm− 2，是裸Fe 2 O3电极的3.5倍。用富含稀土的FeNiOx助催化剂装饰Fe 2 O3/Fe 2 TiO 5异质结光阳极进一步加速了表面反应动力学，导致相对于RHE的0.8 V的起始电势，在1.23 V下光电流为2.7 mA cm− 2，在1.6 V下相对于RHE的光电流为4.6 mA cm− 2。这种三明治光电阳极显示出良好的稳定性为5小时，并实现了95%的整体法拉第效率为O2生成。这是有报道的Fe 2 O3/Fe 2 TiO 5光阳极的最佳性能。
Hematite suffers from poor charge transport and separation properties for solar water splitting. This paper describes the design and fabrication of a 3D Fe2O3/Fe2TiO5heterojunction photoanode with improved charge separation, via a facile hydrothermal method followed by atomic layer deposition and air annealing. A highly crystallized Fe2TiO5phase forms with a distinct interface with the underlying Fe2O3core, where a 4 nm Fe2TiO5overlayer leads to the best photoelectrochemical performance. The favorable band offset between Fe2O3and Fe2TiO5establishes a type‐II heterojunction at the Fe2O3/Fe2TiO5interface, which drives electron–hole separation effectively. The Fe2O3/Fe2TiO5composite electrode exhibits a dramatically improved photocurrent of 1.63 mA cm−2at 1.23 V versus reversible hydrogen electrode (RHE) under simulated 1 sun illumination (100 mW cm−2), which is 3.5 times that of the bare Fe2O3electrode. Decorating the Fe2O3/Fe2TiO5heterojunction photoanode with earth‐abundant FeNiOxcocatalyst further expedites surface reaction kinetics, leading to an onset potential of 0.8 V versus RHE with a photocurrent of 2.7 mA cm−2at 1.23 V and 4.6 mA cm−2at 1.6 V versus RHE. This sandwich photoanode shows an excellent stability for 5 h and achieves an overall Faradaic efficiency of 95% for O2generation. This is the best performance ever reported for Fe2O3/Fe2TiO5photoanodes.