联系我们  |  网站地图  |  English   |  移动版  |  中国科学院 |ARP
站内搜索:
首页 简介 管理部门 科研部门 支撑部门 研究队伍 科研成果 成果转化 研究生教育 党建与创新文化 科普 信息公开 办公内网
科技信息
Low-cost wearables manuf...
Researchers develop 3-D-...
硫化钴能用来制作超级电容
青岛能源所在石墨炔能源存...
二维非铅钙钛矿动力学机理...
Scientists fine-tune sys...
Amorphous diamond synthe...
化学耦合的硫化镍和碳空心...
全无机钙钛矿光电探测器动...
科研人员提出纳米催化医学...
Newly-discovered semicon...
Molecular nanoparticles ...
碳纳米点固态高效发光新方法
基于甲胺气体的钙钛矿薄膜...
新型镁电池可使储能技术更...
现在位置:首页>新闻动态>科技信息
Cheap, efficient and stable photoelectrode could improve water splitting with solar energy
2017-07-04 10:51:33 | 编辑: | 【 【打印】【关闭】

 

Credit: Delft University of Technology

  Water splitting with solar energy could provide an efficient route for large scale renewable energy conversion and storage. Scientists from TU Delft and AMOLF have now engineered a very efficient and stable photoelectrode, a material that absorbs light and directly splits water into hydrogen and oxygen. Furthermore, they use silicon wafers as the light absorbing material, so the system is also cheap. They report on their findings in Nature Communications on Thursday, June 29th.

  Energy conversion 

  Photoelectrochemical (PEC) water splitting (into hydrogen and oxygen) is seen as a sustainable approach to produce clean and renewable fuel by the direct conversion of solar to chemical energy. The hydrogen could, for instance, be used directly in fuel cells or combined with other molecules to create sustainable chemicals.

  'Together with colleagues from AMOLF (Amsterdam), we have engineered a photo-electrode, a material that absorbs light and directly splits water, that has a very high efficiency and over 200 hours of stability', says Wilson Smith, Associate Professor in the Department of Chemical Engineering at TU Delft. 'This is remarkable in a field where people normally show only a few hours of stability. We use silicon wafers as the light absorbing material, so the photoelectrode is also very cheap.'

  'So, in summary, we now have a material that is low cost, absorbs a lot of light, has a high catalytic efficiency, and is remarkably stable'.

  MIS 

  It is essential for a PEC-system to provide a sufficiently high photocurrent and photovoltage to drive the water oxidation reaction. Typically there is a balance between the catalytic efficiency of this system and its long-term stability. Fixing one problem usually makes the other worse. 'Here, we have independently addressed the stability and catalysis bottlenecks in photoelectrochemical water splitting, and combined them into one simple system. We used a newly designed insulator layer to stabilize the semiconductor (Si) photoelectrode, while also using two metals to increase photovoltage and split water with a high efficiency. This approach, known as making a metal-insulator-semiconductor (MIS) junction, has proven efficient previously but never as durable', Smith explains.

  Durability 

  'Despite the great advantage of the MIS structure for solar water splitting, there remains a major trade-off between the high efficiency and the long-term durability', says Smith. Therefore, many efforts have concentrated on protecting the photoelectrodes. Nickel (Ni) is an attractive metal that has all the functionalities required for MIS photoanodes: a high work function for high photovoltage generation, an active catalyst for water oxidation, and high chemical stability in strongly alkaline solution. Ni absorbs light, which can limit the photoelectrode performance, so it must be made very thin (2 nm). However, such a thin Ni layer is not able to completely protect the underlying photoanode in a highly corrosive electrolyte at pH 14.

  Simple 

  The researchers have now developed a MIS photoanode that can yield a high efficiency and high stability by engineering both the metal-insulator and insulator-semiconductor interfaces. Specifically, they have introduced a Al2O3 layer and two metals, Pt and Ni. Using this simple yet effective protection strategy, they obtain more than 200 hour operation of a MIS photoanode that shows constant high photocurrents in a strong basic solution. Thus, the approach used in this study can potentially be integrated into existing PV technology, making it promising for future applications.

  To successfully realise spontaneous water splitting, the photoanode should be combined with larger band gap photoelectrodes in a series or tandem arrangement. This would simplify the design of a highly efficient photoelectrochemical device for solar water splitting.

  Explore further: NREL pioneers better way to make renewable hydrogen 

  More information: Ibadillah A. Digdaya et al. Interfacial engineering of metal-insulator-semiconductor junctions for efficient and stable photoelectrochemical water oxidation, Nature Communications (2017). DOI: 10.1038/NCOMMS15968 

  Journal reference: Nature Communications 

版权所有 中国科学院上海硅酸盐研究所 沪ICP备05005480号
长宁园区地址:上海市长宁区定西路1295号 电话:86-21-52412990 传真:86-21-52413903 邮编:200050
嘉定园区地址:上海市嘉定区和硕路585号  电话:86-21-69906002 传真:86-21-69906700 邮编:201899