Chee Png Mei, Boix Pablo P, Ge Hu, Yanan Fang, Barber James, Wong Lydia Helena
†Solar Fuels Lab, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.
‡Energy Research Institute@NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore 637553.
ACS Appl Mater Interfaces. 2015 Apr 1;7(12):6852-9. doi: 10.1021/acsami.5b00417. Epub 2015 Mar 20.
We report a simple method to produce a stable and repeatable photoanode for water splitting with a core-shell hematite (α-Fe2O3) nanorods system by combining spray pyrolysis and hydrothermal synthesis. Impedance spectroscopy revealed passivation of the surface states by the shell layer, which results in an increase of the charge injection through the hematite conduction band. In pristine hematite more holes are accumulated on the surface and the charge transfer to the electrolyte occurs through surface states, whereas in the core-shell hematite photoanode the majority of hole transfer process occurs through the valence band. As a result the photoactivity of the core-shell nanorods, 1.2 mA cm(-2), at 1.23 V vs RHE, is twice that of pristine hematite nanorods. The alteration of the interface energetics is supported by TEM, showing that the crystallinity of the surface has been improved by the deposition of the shell.
我们报道了一种简单的方法，通过结合喷雾热解和水热合成，制备出一种用于水分解的具有核壳结构赤铁矿（α-Fe2O3）纳米棒系统的稳定且可重复的光阳极。阻抗谱表明壳层使表面态钝化，这导致通过赤铁矿导带的电荷注入增加。在原始赤铁矿中，更多的空穴积累在表面，电荷通过表面态转移到电解质中，而在核壳结构赤铁矿光阳极中，大多数空穴转移过程通过价带发生。结果，核壳纳米棒在相对于可逆氢电极（RHE）为1.23 V时的光活性为1.2 mA cm(-2)，是原始赤铁矿纳米棒的两倍。透射电子显微镜（TEM）支持了界面能量学的改变，表明壳层的沉积改善了表面的结晶度。
