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：2014
卷号：111
期号：42
页码：14990-14994
DOI：10.1073/pnas.1416697111
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceConversion of CO2 into liquid fuels is one of the most important contemporary energy and environmental challenges. As a first step in this direction, the electrochemical reduction of CO2 to CO requires catalysts, usually derived from transition metal complexes. In this paper, a very efficient, electrogenerated iron-porphyrin catalyst was obtained by introducing both pendant acid groups and fluorine substituents in the molecule. The former stabilize the CO2-catalyst key intermediate via H bonding and provide a high local proton concentration. The latter help decrease the energy required to drive catalysis. Benchmarking this molecule with other catalysts shows that it is at present the most efficient, to the best of our knowledge, homogeneous molecular catalyst of the CO2-to-CO conversion in terms of selectivity, overpotential, and turnover frequency. A very efficient electrogenerated Fe0 porphyrin catalyst was obtained by substituting in tetraphenylporphyrin two of the opposite phenyl rings by ortho-, ortho'-phenol groups while the other two are perfluorinated. It proves to be an excellent catalyst of the CO2-to-CO conversion as to selectivity (the CO faradaic yield is nearly quantitative), overpotential, and turnover frequency. Benchmarking with other catalysts, through catalytic Tafel plots, shows that it is the most efficient, to the best of our knowledge, homogeneous molecular catalyst of the CO2-to-CO conversion at present. Comparison with another Fe0 tetraphenylporphyrin bearing eight ortho-, ortho'-phenol functionalities launches a general strategy where changes in substituents will be designed so as to optimize the operational combination of all catalyst elements of merit.
关键词：solar fuels ; CO2 reduction ; electrochemistry ; catalysis ; contemporary energy challenges
