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

非技术描述：燃料电池是未来能源系统的基石，其功能依赖于强大而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含碳的纳米结构碳化物表面来解决这个关键问题。本研究结合了一组新型富碳碳化物表面的合成和表征，以及与氧和水的关键化学反应的表面科学分析方法的观察。它处于基础研究和应用研究的交叉点，具有决定性地扩大有效催化剂材料范围的潜力。技术细节：过渡金属碳化物表面，如碳化钨，是燃料电池、蒸汽重整和催化剂载体中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易氧化，这会改变和降低性能。目前的研究是基于这样的假设，即可以设计出富含碳的纳米结构碳化物表面，从而使氧化降解最小化。使用与分子束外延密切相关的方法生长非化学计量碳化钨，并使用一套互补的表面科学技术观察与水和氧反应过程中的表面转变。这项研究将表面特征与从原子到中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。这项研究与教育组成部分相结合，使公众和各级学生参与其中。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”，以及与NISE（纳米非正式科学教育，http://www.nisenet.org/）的强有力合作。

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/).