In pursuit of a cheaper alternative to the rare platinum as catalyst to producing hydrogen in a fuel cell, researchers from University of California (UC) Davis are utilizing a Japanese synchrotron in trying to unravel the catalytic mechanism behind enzymes called ‘hydrogenases’ that can also yield hydrogen, and be able to mimic these enzymes.
Hydrogenases catalyze a simple reduction-oxidation of hydrogen atoms into H2 molecule and vice versa at the enzymes’ active sites. UC Davis researchers investigated a type of hydrogenase that have the metals nickel (Ni) and iron (Fe) as their active sites, and thus, they are called ‘[NiFe] hydrogenase.’
To analyze the chemical structure of the reduced [NiFe] hydrogenase sample, nuclear resonance vibrational spectroscopy (NRVS) measurement was conducted using the Spring-8 synchrotron. The researchers found additional information regarding the enzyme’s active site.
It has been known that the [NiFe] hydrogenase’s structure has two subunits – one contains the Ni-Fe active site the other contains the Fe-S (iron-sulfur) clusters. The figure above shows the molecular structure (top) and the atomic vibrations obtained from the NRVS measurement (below). The smaller subunit (green) in the molecular structure contains the Fe-S clusters, while the larger subunit (blue) contains the Ni-Fe part.
The UC Davis researchers found two bonds, Fe-CO and Fe-CN, present at the subunit containing the active site Ni-Fe.
These new information may lead to deeper understanding of the catalyzing mechanism of NiFe hydrogenases that may enable researchers to mimic them to produce greener energy.