RT Journal Article
SR Electronic
T1 A Synthetic Nickel Electrocatalyst with a Turnover Frequency Above 100,000 s<sup>−1</sup> for H<sub>2</sub> Production
JF Science
JO Science
FD American Association for the Advancement of Science
SP 863
OP 866
DO 10.1126/science.1205864
VO 333
IS 6044
A1 Helm, Monte L.
A1 Stewart, Michael P.
A1 Bullock, R. Morris
A1 DuBois, M. Rakowski
A1 DuBois, Daniel L.
YR 2011
UL http://science.sciencemag.org/content/333/6044/863.abstract
AB Reduction of acids to molecular hydrogen as a means of storing energy is catalyzed by platinum, but its low abundance and high cost are problematic. Precisely controlled delivery of protons is critical in hydrogenase enzymes in nature that catalyze hydrogen (H2) production using earth-abundant metals (iron and nickel). Here, we report that a synthetic nickel complex, [Ni(PPh2NPh)2](BF4)2, (PPh2NPh = 1,3,6-triphenyl-1-aza-3,6-diphosphacycloheptane), catalyzes the production of H2 using protonated dimethylformamide as the proton source, with turnover frequencies of 33,000 per second (s−1) in dry acetonitrile and 106,000 s−1 in the presence of 1.2 M of water, at a potential of –1.13 volt (versus the ferrocenium/ferrocene couple). The mechanistic implications of these remarkably fast catalysts point to a key role of pendant amines that function as proton relays.