Abstract
The splitting of dinitrogen (N2) and reduction to ammonia (NH3) is a kinetically complex and energetically challenging multistep reaction. In the Haber-Bosch process, N2 reduction is accomplished at high temperature and pressure, whereas N2 fixation by the enzyme nitrogenase occurs under ambient conditions using chemical energy from adenosine 5-Œ-triphosphate (ATP) hydrolysis.We show that cadmium sulfide (CdS) nanocrystals can be used to photosensitize the nitrogenase molybdenum-iron (MoFe) protein, where light harvesting replaces ATP hydrolysis to drive the enzymatic reduction of N2 into NH3. The turnover rate was 75 per minute, 63% of the ATP-coupled reaction rate for the nitrogenase complex under optimal conditions. Inhibitors of nitrogenase (i.e., acetylene, carbon monoxide, and dihydrogen) suppressed N2 reduction. The CdS:MoFe protein biohybrids provide a photochemical model for achieving light-driven N2 reduction to NH3.
| Original language | English |
|---|---|
| Pages (from-to) | 448-450 |
| Number of pages | 3 |
| Journal | Science |
| Volume | 352 |
| Issue number | 6284 |
| DOIs | |
| State | Published - Apr 22 2016 |
| Externally published | Yes |
Funding
K.A.B. and P.W.K. were supported by a Laboratory Directed Research and Development Program seed project at the National Renewable Energy Laboratory for CdS:MoFe protein photochemical H2 production experiments, and by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences; and the U.S. Department of Energy under Contract no. DE-AC36-08-GO28308 with the National Renewable Energy Laboratory for CdS:MoFe protein biohybrid N2 reduction experiments. M.B.W., H.H., and G.D. conducted .