Efficient Photoelectrochemical Water Splitting with Ultrathin films of Hematite on Three-Dimensional Nanophotonic Structures
| Autor: | Zhiyong Fan, Bo Hua, Siu-Fung Leung, Shihe Yang, Qingfeng Lin, Qianpeng Zhang, Yongcai Qiu, Zhanhua Wei, Yuegang Zhang, Kwong Hoi Tsui |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Materials science
Hydrogen Mechanical Engineering Energy conversion efficiency Nanophotonics chemistry.chemical_element Bioengineering Nanotechnology General Chemistry Hematite Condensed Matter Physics Electrochemistry Active layer chemistry visual_art visual_art.visual_art_medium Water splitting General Materials Science Electronic band structure |
| Zdroj: | Nano Letters. 14:2123-2129 |
| ISSN: | 1530-6992 1530-6984 |
| DOI: | 10.1021/nl500359e |
| Popis: | Photoelectrochemical (PEC) solar water splitting represents a clean and sustainable approach for hydrogen (H2) production and substantial research are being performed to improve the conversion efficiency. Hematite (α-Fe2O3) is considered as a promising candidate for PEC water splitting due to its chemical stability, appropriate band structure, and abundance. However, PEC performance based on hematite is hindered by the short hole diffusion length that put a constraint on the active layer thickness and its light absorption capability. In this work, we have designed and fabricated novel PEC device structure with ultrathin hematite film deposited on three-dimensional nanophotonic structure. In this fashion, the nanophotonic structures can largely improve the light absorption in the ultrathin active materials. In addition, they also provide large surface area to accommodate the slow surface water oxidation process. As the result, high current density of 3.05 mA cm(-2) at 1.23 V with respect to the reversible hydrogen electrode (RHE) has been achieved on such nanophotonic structure, which is about three times of that for a planar photoelectrode. More importantly, our systematic analysis with experiments and modeling revealed that the design of high performance PEC devices needs to consider not only total optical absorption, but also the absorption profile in the active material, in addition to electrode surface area and carrier collection. |
| Databáze: | OpenAIRE |
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