2011/08/11 by Monte L. Helm, Michael Stewart, R. Morris Bullock +2 · 3 citations
Energy · #Electrocatalysts for Energy Conversion #Metalloenzymes and iron-sulfur proteins #CO2 Reduction Techniques and Catalysts
paper · doi:10.1126/science.1205864
openalex publication_date 2011/08/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
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 (H(2)) production using earth-abundant metals (iron and nickel). Here, we report that a synthetic nickel complex, [Ni(P(Ph)(2)N(Ph))(2)](BF(4))(2), (P(Ph)(2)N(Ph) = 1,3,6-triphenyl-1-aza-3,6-diphosphacycloheptane), catalyzes the production of H(2) 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.