Chen Hongjun, Lyu Miaoqiang, Liu Gang, Wang Lianzhou
Nanomaterials Centre, School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia.
Shenyang National Lab for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, 110016, Shenyang (P.R. China.
Chemistry. 2016 Mar 24;22(14):4802-8. doi: 10.1002/chem.201504512. Epub 2016 Feb 16.
A simple, wet-chemical method for the synthesis of an FeOOH nanorod-array photoelectrode on fluorine-doped tin oxide (FTO) glass is reported. Nanorods of diameter about 35 nm and length about 300 nm have been vertically grown on an FTO substrate. Upon calcination, the FeOOH phase could be easily converted to a hematite structure while maintaining the shape of the nanorod array. An interesting abnormal cathodic photocurrent is generated on the FeOOH nanorod-array photoelectrode under illumination, which is totally different from that obtained on a calcined hematite photoelectrode under the same experimental conditions. The cathodic photocurrent density generated on the FeOOH photoelectrode can also be tuned by applying an electrochemical anodic or cathodic treatment. Detailed analysis has revealed that higher valence state Fe(IV) species in the FeOOH photoelectrode play an important role in sacrificing the photoexcited electrons for generation of the cathodic photocurrent. Comparison between the FeOOH and hematite photoelectrodes allows for a better understanding of the interplay between crystal structure, surface reactions, and photocurrent. The findings on this new abnormal phenomenon could also provide guidance for the design of new types of semiconducting photoelectrochemical devices.
报道了一种在氟掺杂氧化锡（FTO）玻璃上合成FeOOH纳米棒阵列光电极的简单湿化学方法。直径约35 nm、长度约300 nm的纳米棒已垂直生长在FTO衬底上。煅烧后，FeOOH相可轻松转化为赤铁矿结构，同时保持纳米棒阵列的形状。在光照下，FeOOH纳米棒阵列光电极上会产生一种有趣的异常阴极光电流，这与在相同实验条件下煅烧赤铁矿光电极上获得的光电流完全不同。FeOOH光电极上产生的阴极光电流密度也可通过电化学阳极或阴极处理进行调节。详细分析表明，FeOOH光电极中较高价态的Fe(IV)物种在牺牲光激发电子以产生阴极光电流方面起着重要作用。FeOOH光电极与赤铁矿光电极之间的比较有助于更好地理解晶体结构、表面反应和光电流之间的相互作用。关于这种新异常现象的发现也可为新型半导体光电化学器件的设计提供指导。
