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：2008
卷号：105
期号：31
页码：10654-10658
DOI：10.1073/pnas.0801290105
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Carbon dioxide (CO2) is a kinetically and thermodynamically stable molecule. It is easily formed by the oxidation of organic molecules, during combustion or respiration, but is difficult to reduce. The production of reduced carbon compounds from CO2 is an attractive proposition, because carbon-neutral energy sources could be used to generate fuel resources and sequester CO2 from the atmosphere. However, available methods for the electrochemical reduction of CO2 require excessive overpotentials (are energetically wasteful) and produce mixtures of products. Here, we show that a tungsten-containing formate dehydrogenase enzyme (FDH1) adsorbed to an electrode surface catalyzes the efficient electrochemical reduction of CO2 to formate. Electrocatalysis by FDH1 is thermodynamically reversible--only small overpotentials are required, and the point of zero net catalytic current defines the reduction potential. It occurs under thoroughly mild conditions, and formate is the only product. Both as a homogeneous catalyst and on the electrode, FDH1 catalyzes CO2 reduction with a rate more than two orders of magnitude faster than that of any known catalyst for the same reaction. Formate oxidation is more than five times faster than CO2 reduction. Thermodynamically, formate and hydrogen are oxidized at similar potentials, so formate is a viable energy source in its own right as well as an industrially important feedstock and a stable intermediate in the conversion of CO2 to methanol and methane. FDH1 demonstrates the feasibility of interconverting CO2 and formate electrochemically, and it is a template for the development of robust synthetic catalysts suitable for practical applications.
关键词：electrocatalysis ; formate dehydrogenase ; formate oxidation ; protein film voltammetry ; carbon dioxide reduction
