Origin of low CO2 selectivity on platinum in the direct ethanol fuel cell.
Origin of low CO2 selectivity on platinum in the direct ethanol fuel cell.
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DOI：
10.1002/anie.201104990
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发表时间：
2012-02-13
影响因子：
16.6
通讯作者：
Hu, P.
中科院分区：
文献类型：
--
作者：
Kavanagh, Richard;Cao, Xiao-Ming;Lin, Wen-Feng;Hardacre, Christopher;Hu, P.
直接乙醇燃料电池（DEFC）代表了现代研究中最令人兴奋的未来清洁能源解决方案之一，因为乙醇可以从生物质中可持续生产，相对无毒，而且最重要的是，具有高能量密度。[1-8]卓越的能量密度是由于在完全电化学氧化过程中从乙醇转移了 12 个电子（而不是来自甲醇的 6 个电子或来自氢气的 2 个电子）。这种装置的实用性取决于其选择性催化乙醇完全氧化为CO2的能力。 [9, 10] 然而，目前乙醇燃料电池中的CO2选择性非常低，在大多数报道的系统中主要产物是乙酸（仅导致四个电子的转移）和乙醛（仅导致两个电子）。 [11-13] 在此，我们解决了乙醇燃料电池中CO2选择性低的根源。 DEFC，可以说是该领域需要回答的最重要的问题，使用第一性原理计算。DEFC 的开创性工作可以追溯到 20 世纪 50 年代，[14] 但直到后来才用红外光谱对选择性进行了全面研究，显示 CO2 是一种次要产物。 [15] Behm 及其同事 [1] 对各种条件下和采用各种形貌的选择性进行了彻底的研究，他们令人信服地表明，铂催化剂对 CO2 的选择性在 0.5-7.5% 范围内，这远远低于经济实施该技术所需的选择性。事实证明这个问题很难凭经验克服。最近的工作在活性和选择性方面取得了重大进展，[2]但还需要进一步改进。理论研究已经取得了相当大的进展 [2, 16–18] 并确定铂单原子步骤是最有可能发生乙醇完全氧化的位点，并得出结论认为密堆积表面是不合适的。 [17]尽管已经进行了大量的实验和理论工作，但二氧化碳形成的抑制因素仍不清楚。这样做有充分的理由：1）催化反应发生在固体表面上
The direct ethanol fuel cell (DEFC) represents one of the most exciting future clean energy solutions in modern research, because ethanol can be sustainably produced from biomass, is relatively nontoxic and, most importantly, has a high energy density.[1–8] The exceptional energy density is due to the transfer of 12 electrons from ethanol during complete electrochemical oxidation (as opposed to six electrons from methanol or two from hydrogen). The practicality of such a device is contingent on its ability to selectively catalyze the total oxidation of ethanol to CO2.[9, 10] However, the CO2 selectivity in the current ethanol fuel cells is very low, and the main products are acetic acid (resulting in the transfer of only four electrons) and acetaldehyde (only two electrons) in most systems reported.[11–13] Herein, we address the origin of low CO2 selectivity in the DEFC, arguably the most important question to be answered in the field, using first-principles calculations.The pioneering work on DEFCs can be traced back to the 1950s,[14] but it was not until later that the selectivity was comprehensively investigated with IR spectroscopy showing CO2 to be a minor product.[15] Behm and co-workers [1] performed a thorough investigation on the selectivity under a wide range of conditions and employing a wide range of morphologies, and they convincingly showed that platinum catalysts exhibit selectivity towards CO2 in the region of 0.5–7.5%, which is far short of the selectivity needed for economic implementation of the technology. This problem has proven difficult to surmount empirically. Recent work has made significant progress in terms of activity and selectivity,[2] but further improvements are required. Theoretical studies have made considerable advances [2, 16–18] and identified the platinum monoatomic step as the most likely site for total ethanol oxidation and concluded that the close-packed surfaces are unsuitable.[17] Despite the extensive experimental and theoretical work that has been carried out, the inhibiting factors in CO2 formation remain unclear. There are good reasons for this: 1) the catalytic reactions occur on solid surfaces in the
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影响因子：
41.2
作者：
Kowal, A.;Li, M.;Adzic, R. R.
通讯作者：
Adzic, R. R.
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