Water oxidation and oxygen monitoring by cobalt-modified fluorine-doped tin oxide electrodes Article

Kent, CA, Concepcion, JJ, Dares, CJ et al. (2013). Water oxidation and oxygen monitoring by cobalt-modified fluorine-doped tin oxide electrodes . JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 135(23), 8432-8435. 10.1021/ja400616a

cited authors

  • Kent, CA; Concepcion, JJ; Dares, CJ; Torelli, DA; Rieth, AJ; Miller, AS; Hoertz, PG; Meyer, TJ

authors

abstract

  • Electrocatalytic water oxidation occurs at fluoride-doped tin oxide (FTO) electrodes that have been surface-modified by addition of Co(II). On the basis of X-ray photoelectron spectroscopy and transmission electron microscopy measurements, the active surface site appears to be a single site or small-molecule assembly bound as Co(II), with no evidence for cobalt oxide film or cluster formation. On the basis of cyclic voltammetry measurements, surface-bound Co(II) undergoes a pH-dependent 1e-/1H+ oxidation to Co(III), which is followed by pH-dependent catalytic water oxidation. O2 reduction at FTO occurs at -0.33 V vs NHE, allowing for in situ detection of oxygen as it is formed by water oxidation on the surface. Controlled-potential electrolysis at 1.61 V vs NHE at pH 7.2 resulted in sustained water oxidation catalysis at a current density of 0.16 mA/cm 2 with 29 000 turnovers per site over an electrolysis period of 2 h. The turnover frequency for oxygen production per Co site was 4 s-1 at an overpotential of 800 mV at pH 7.2. Initial experiments with Co(II) on a mesoporous, high-surface-area nanoFTO electrode increased the current density by a factor of ∼5. © 2013 American Chemical Society.

publication date

  • June 12, 2013

published in

Digital Object Identifier (DOI)

start page

  • 8432

end page

  • 8435

volume

  • 135

issue

  • 23