A Tantalum Nitride Photoanode Modified with a Hole‐Storage Layer for Highly Stable Solar Water Splitting

• DOI: 10.1002/anie.201404697
• Publication Date: 2014-05-30T21:27:58Z
• Authors: Guiji Liu; Jingying Shi; Fuxiang Zhang; Zheng Chen; Jingfeng Han; Chunmei Ding; Shanshan Chen; Zhiliang Wang; Hongxian Han; Can Li
• Keywords: Oxygen Evolution Reaction; 660; Impedance; Conversion; 02 engineering and technology; 7. Clean energy; Ta3N5 Nanorod Arrays; Efficient; Oxidation; Photocurrent; Ferrihydrite; Catalyst; 0210 nano-technology; Electrodes

AbstractPhotoelectrochemical (PEC) water splitting is an ideal approach for renewable solar fuel production. One of the major problems is that narrow bandgap semiconductors, such as tantalum nitride, though possessing desirable band alignment for water splitting, suffer from poor photostability for water oxidation. For the first time it is shown that the presence of a ferrihydrite layer permits sustainable water oxidation at the tantalum nitride photoanode for at least 6 h with a benchmark photocurrent over 5 mA cm−2, whereas the bare photoanode rapidly degrades within minutes. The remarkably enhanced photostability stems from the ferrihydrite, which acts as a hole‐storage layer. Furthermore, this work demonstrates that it can be a general strategy for protecting narrow bandgap semiconductors against photocorrosion in solar water splitting.