期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2021
卷号：118
期号：51
DOI：10.1073/pnas.2115059118
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
The mechanisms by which abiotic, long-chain hydrocarbons are produced in natural alkaline hydrothermal systems are unknown, as only short-chain hydrocarbons (<5 carbons) have been experimentally observed to date. Here, we demonstrate how the hydrothermal reduction of bicarbonate into long-chain hydrocarbons (≤24 carbons) occurs through the use of iron and cobalt metals. In contrast to the traditional Fischer–Tropsch synthesis, in which water is the driving force for catalyst deactivation, Co exhibits unique catalytic stability in hydrothermal conditions through bicarbonate-assisted CoO
x reduction, thus promoting the carbon−carbon coupling process with the synergistic effect from the iron hydroxyl group. This finding helps to explain the abiogenic origin of petroleum, life’s emergence, and further contributes to artificial carbon dioxide utilization in the chemical industry.
Abiotic CO
2 reduction on transition metal minerals has been proposed to account for the synthesis of organic compounds in alkaline hydrothermal systems, but this reaction lacks experimental support, as only short-chain hydrocarbons (<C
5) have been synthesized in artificial simulation. This presents a question: What particular hydrothermal conditions favor long-chain hydrocarbon synthesis? Here, we demonstrate the hydrothermal bicarbonate reduction at ∼300 °C and 30 MPa into long-chain hydrocarbons using iron (Fe) and cobalt (Co) metals as catalysts. We found the Co
0 promoter responsible for synthesizing long-chain hydrocarbons to be extraordinarily stable when coupled with Fe−OH formation. Under these hydrothermal conditions, the traditional water-induced deactivation of Co is inhibited by bicarbonate-assisted CoO
x reduction, leading to honeycomb-native Co nanosheets generated in situ as a new motif. The Fe−OH formation, confirmed by operando infrared spectroscopy, enhances CO adsorption on Co, thereby favoring further reduction to long-chain hydrocarbons (up to C
24). These results not only advance theories for an abiogenic origin for some petroleum accumulations and the hydrothermal hypothesis of the emergence of life but also introduce an approach for synthesizing long-chain hydrocarbons by nonnoble metal catalysts for artificial CO
2 utilization.
关键词：abiotic synthesis; hydrothermal petroleum; long-chain hydrocarbon; carbon cycle; origin of life
