Investigation of the Oxidation of Stoichiometric and Carbon-Rich Tungsten Carbide Surfaces

化学计量和富碳碳化钨表面的氧化研究

• 批准号: 1005809
• 负责人: Petra Reinke
• 金额: $ 27.5万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1005809&HistoricalAwards=false
• 关键词: Investigation; Oxidation; Stoichiometric; Carbon; Rich

NON-TECHNICAL DESCRIPTION: Fuel cells are a cornerstone of future energy systems, and their functionality relies on the presence of a powerful and durable catalyst material. The majority of catalysts used in current fuel cell technology are based on costly noble metal materials. An alternative is the use of tungsten carbide, which is also compatible with novel microbial fuel cells. Unfortunately, carbide performance is hindered by surface oxidation. The current project aims to design carbon-rich, nano-structured carbide surfaces to remedy this critical issue. The investigation combines the synthesis and characterization of a set of novel carbon-rich carbide surfaces, and the observation with surface science analytical methods of the critical chemical reactions with oxygen and water. It is positioned at the intersection between fundamental and applied research, and has the potential to decisively broaden the range of effective catalyst materials. TECHNICAL DETAILS: Transition metal carbide surfaces such as tungsten carbide, are promising substitutes for noble metal catalysts in fuel cells, steam reforming and as a catalyst support. A critical limitation to their use is their susceptibility to oxidation, which modifies and depresses performance. The present study is based on the hypothesis that a carbon-rich, nanostructured carbide surface can be designed, where degradation through oxidation is minimized. A non-stoichiometric tungsten carbide is grown using a method that is closely related to molecular beam epitaxy, and the transformation of the surface during the reaction with water and oxygen is observed with a suite of complementary surface science techniques. This investigation connects surface characteristics to reactivity from the atomic to the mesoscale, and opens the pathway to the design of advanced tungsten carbide catalysts. The research is coupled with an educational component that engages the public and students at all levels. A particular focus is informal science education, which includes the design of a new exhibit, the "Energy Corner", and a strong collaboration with NISE (Nanoscale Informal Science Education, http://www.nisenet.org/).

非技术描述：燃料电池是未来能源系统的基石，它们的功能依赖于强大和耐用的催化剂材料的存在。目前燃料电池技术中使用的大多数催化剂都是基于昂贵的贵金属材料。另一种选择是使用碳化钨，它也与新型微生物燃料电池兼容。不幸的是，碳化物的性能受到表面氧化的阻碍。目前的项目旨在设计富碳的纳米结构碳化物表面来解决这一关键问题。这项研究结合了一系列新型富碳碳化物表面的合成和表征，以及用表面科学分析方法观察到与氧和水的临界化学反应。它位于基础研究和应用研究的交汇点，有可能决定性地拓宽有效催化剂材料的范围。技术细节：过渡金属碳化物表面，如碳化钨，是燃料电池、水蒸气重整和催化剂载体等贵金属催化剂的有前途的替代品。它们使用的一个关键限制是它们对氧化的敏感性，氧化会改变和抑制性能。目前的研究是基于这样一个假设，即可以设计出富碳的纳米结构碳化物表面，其中氧化降解最小。用一种与分子束外延密切相关的方法生长了非化学计量碳化钨，并用一套互补的表面科学技术观察了与水和氧气反应过程中表面的变化。这项研究将表面特性与从原子到介观尺度的反应性联系起来，为设计先进的碳化钨催化剂开辟了道路。这项研究还结合了一个教育部分，让公众和各级学生都参与进来。特别关注的是非正式科学教育，其中包括设计一个新的展览--“能源角”，并与NISE(纳米非正式科学教育，http://www.nisenet.org/).)进行强有力的合作