Production of H2 at fast rates using a nickel electrocatalyst in water–acetonitrile solutions

Abstract

We report a synthetic nickel complex containing proton relays, [Ni(P(Ph)2N(C6H4OH)2)2](BF4)2 (P(Ph)2N(C6H4OH)2 = 1,5-bis(p-hydroxyphenyl)-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclo-octane), that catalyzes the production of H2 in aqueous acetonitrile with turnover frequencies of 750-170,000 s(-1) at experimentally determined overpotentials of 310-470 mV.

Combining theory and experiment in electrocatalysis: Insights into materials design

“…Homogeneous catalysts with high TOF avg have also been developed, though they typically require large overpotentials to reach appreciable current densities (Fig. 3B) (67)(68)(69).…”

Biomimetic Complexes for Production of Dihydrogen and Reduction of CO2

“…Second, systematic studies have been undertaken to map structure-function relationships [104,105]. Third, extraordinarily high turnover frequencies exceeding 10 4 s À1 have been reported [106][107][108]. As a substitute for the eight-membered diphosphine, the seven-membered ligand P Ph 2 N Ph ¼1,3,6-triphenyl-1-aza-3,6-diphosphacycloheptane has also been employed as a means to prevent formation of an unproductive isomer in which a proton is pinched between the two amines of a single ligand (Fig.…”

Multidisciplinary approaches to solar hydrogen

“…Furthermore, the inspiration for many of the molecular catalysts for hydrogen evolution comes from the structure and function of natural hydrogenases [33,[113][114][115]. Recently, chemists have turned to concepts from biology such as the use of proton relays to deliver substrate to the active site, resulting in an increase in the efficiency of molecular catalysts [40,41]. Rather than working to mimic biology, another approach is to use nature's highly evolved biomolecular structures directly in assemblies for artificial photosynthesis.…”

“…Molecular catalysts with longevities of over 60 h [29], turnover frequencies over 100 000 s 21 [40,41], and overpotentials of only a few hundred millivolts or less [41] have resulted. There also has been recent progress on molecular catalysts that are active in water -solvent mixtures [27,40,42] and even in neutral pH water [29,39].…”