Abstract Natural gas is an important energy resource for electric power generation and other energy needs. Recent discoveries of vast reserves of shale gas greatly increased its abundance while lowering its cost. Combined with its significantly smaller carbon-footprint than coal, natural gas has increasingly become the preferred choice to generate electrical power even at the expense of converting existing coal fired power plants to run on natural gas. However, most natural gas combustion-based power plants currently operate at efficiencies in the low 30%. Conversion of natural gas in solid oxide fuel cells (SOFC) promises to increase system level conversion efficiencies to above 60%, doubling the current efficiencies and significantly reducing the CO 2 emissions by a factor of 2. Such dramatic improvements in conversion efficiency and ease of CO 2 capture are currently out of reach for the combustion-based power generation technologies. Equally importantly, the CO 2 produced from methane conversion leaves the fuel cell in a highly concentrated form. As nitrogen is blocked off by the impervious ceramic electrolyte of the SOFC from entering the process stream, methane oxidation produces a flue stream that is primarily made of the oxidation products CO 2 and steam. The latter can easily be condensed out to capture CO 2 , thus eliminating the need for expensive and energy intensive post separation operations otherwise required to separate CO 2 from N 2 for storage purposes. So if successfully developed and deployed widely, natural gas conversion in SOFCs will greatly reduce CO 2 emissions, help mitigate climate change, and minimize the environmental impact of power generation. This article organizes and critically reviews the current state of understanding in methane catalysis and oxidation with particular emphasis for electrochemical conversion in SOFCs. It presents a comprehensive review of a vast volume of published work (>600 references) extending from fundamental studies in C H bond activation and methane catalysis to basic concepts of electrochemical conversion in fuel cells, to strategies for effective utilization of methane in SOFCs, and associated technical difficulties such as deactivation due to sulfur and carbon yet to be overcome for realizing natural gas conversion, to impactful opportunities provided by recent theoretical advances in computational catalysis and materials screening studies, and innovative concepts such as strain effects and nanostructuring toward enhancing catalytic rates. It provides tutorial-type information at the appropriate level for the uninitiated but interested reader as well as critical discussions of fundamental phenomena and assessment of recent advances for active researchers in the field. The article is weighted around materials and surface properties and provides an in-depth review with emphasis on electronic structure, charge transport and catalysis. It presents an impartial evaluation of the opportunities as well as the challenges to natural gas utilization in SOFCs. Finally, it concludes that natural gas conversion in SOFCs promises very attractive opportunities for efficient and environmentally friendly power generation, while recognizing and offering in-depth discussions of the challenges facing this technology before it can be considered for large-scale power generation applications.

中文翻译：

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固体氧化物燃料电池中甲烷转化的综合回顾：天然气高效发电的前景

摘要 天然气是满足发电和其他能源需求的重要能源。最近发现的大量页岩气储量大大增加了其储量，同时降低了其成本。再加上其碳足迹比煤炭小得多，天然气日益成为发电的首选选择，即使不惜将现有燃煤发电厂转换为使用天然气也是如此。然而，大多数基于天然气燃烧的发电厂目前以 30% 的低效率运行。固体氧化物燃料电池 (SOFC) 中的天然气转化有望将系统级转化效率提高到 60% 以上，将当前效率提高一倍，并将 CO 2 排放量显着减少 2 倍。目前，基于燃烧的发电技术无法实现如此显着的转化效率改进和 CO 2 捕获的简易性。同样重要的是，甲烷转化产生的 CO 2 以高度浓缩的形式离开燃料电池。由于氮被 SOFC 的不可渗透陶瓷电解质阻止进入工艺流，因此甲烷氧化会产生主要由氧化产物 CO 2 和蒸汽组成的烟道流。后者可以很容易地冷凝出来以捕获 CO 2 ，​​从而消除了对昂贵且能量密集的后分离操作的需要，否则需要将 CO 2 与 N 2 分离以用于存储目的。因此，如果成功开发和广泛部署，SOFC 中的天然气转化将大大减少 CO 2 排放，有助于缓解气候变化，并尽量减少发电对环境的影响。本文组织并批判性地回顾了对甲烷催化和氧化的当前理解状态，特别强调了 SOFC 中的电化学转化。它全面回顾了大量已发表的工作（>600 篇参考文献），从 CH 键活化和甲烷催化的基础研究到燃料电池电化学转化的基本概念，再到在 SOFC 中有效利用甲烷的策略，以及相关的实现天然气转化尚未克服的硫和碳导致的失活等技术困难，以及计算催化和材料筛选研究的最新理论进展提供的有影响的机会，以及旨在提高催化速率的创新概念，例如应变效应和纳米结构。它为未入门但感兴趣的读者提供适当级别的教程类型信息，并为该领域的活跃研究人员提供对基本现象的批判性讨论和对最新进展的评估。这篇文章侧重于材料和表面特性，并提供了深入的评论，重点是电子结构、电荷传输和催化。它对 SOFC 中天然气利用的机遇和挑战进行了公正的评估。最后，结论是 SOFC 中的天然气转化为高效环保的发电提供了非常有吸引力的机会，