Journal
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume 131, Issue 43, Pages 15578-+Publisher
AMER CHEMICAL SOC
DOI: 10.1021/ja9063298
Keywords
-
Categories
Funding
- NSF
- Office of Naval Research
- Division Of Chemistry
- Direct For Mathematical & Physical Scien [0950320] Funding Source: National Science Foundation
Ask authors/readers for more resources
We describe the first example of redox catalysis using a dissolved electroactive nanoparticle, based on the oxidation of water by electrogenerated IrOx nanoparticles containing Ir-VI states, in pH 13 solutions of 1.6 +/- 0.6 nm (dia.) (IrOx)-O-IV nanoparticles capped solely by hydroxide. At potentials (ca. +0.45 V) higher than the mass transport-controlled plateau of the nanoparticle Ir-V/VI wave, rising large redox catalytic currents reflect electrochemical generation of Ir-VI states, which by +0.55 V and onward to +1.0 V are shown by rotated ring disk electrode experiments to lead with 100% current efficiency to the oxidation of water to O-2, O-2 production at +0.55 V corresponds to an overpotential eta of only 0.29 V, relative to thermodynamic expectations of the four electron H2O -> O-2 reaction. The Ir site turnover frequency (TO, mol O-2/Ir sites/s) is 8-11 s(-1). Controlled potential coulometry shows that all Ir sites in these nanoparticles (average 66 Ir each) are electroactive, meaning that the nanoparticles are small enough to allow the required electron and proton transport throughout. Both the overpotential and TO values are nearly the same as those observed previously for films electroflocculated from similar IrOx nanoparticles, providing the first comparison of electrocatatysis by nanoparticte films with redox catalysis by dissolved, diffusing nanoparticles.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available