Molybdenum Sulfide: A Bioinspired Electrocatalyst for Dissimilatory Ammonia Synthesis with Geoelectrical Current
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- 作者：Yamei Li ; Akira Yamaguchi ; Masahiro Yamamoto ; Ken Takai ; Ryuhei Nakamura
- 刊名：Journal of Physical Chemistry C
- 出版年：2017
- 出版时间：February 2, 2017
- 年：2017
- 卷：121
- 期：4
- 页码：2154-2164
- 全文大小：698K
- ISSN：1932-7455
文摘
Abiotic reduction of nitrate/nitrite to ammonia in ancient ocean environments is essential for prebiotic chemical evolution and the early evolution of cellular metabolisms. Although Fe-bearing minerals have been extensively studied as reductants, the incompatibility of these reactions with the paleo-oceanic chemical conditions would have contributed only to low conversion rates. A recent model of prebiotic synthesis driven by geoelectricity suggests that less-abundant transition metals might have played a role in ammonia synthesis. Herein, we report that the electrochemical reduction of nitrate/nitrite to ammonia is effectively catalyzed by molybdenum sulfide over a wide pH range (pH 3–11). The pH dependence of the onset potential of the denitrification current indicates that this superior activity is due to the ability to induce concerted proton–electron transfer (CPET), contributing to a turnover frequency comparable to those of the extant Mo-dependent nitrate reductases. In a manner similar to biological dissimilatory denitrification, molybdenum sulfide catalyzes nitrite reduction to ammonia through NO and N2O intermediates, as revealed by online differential electrochemical mass spectroscopy. These findings demonstrate that molybdenum sulfide functions as a new family of bioinspired electrochemical denitrification catalysts and suggest that molybdenum, the indispensable element in extant denitrification enzymes, likely played an essential role in prebiotic ammonia synthesis with the continuous supply of geoelectrical current.