TY - JOUR
T1 - Anodic deposition of colloidal iridium oxide thin films from hexahydroxyiridate(IV) solutions
AU - Zhao, Yixin
AU - Vargas-Barbosa, Nella M.
AU - Hernandez-Pagan, Emil A.
AU - Mallouk, Thomas E.
PY - 2011/7/18
Y1 - 2011/7/18
N2 - A facile, in-situ deposition route to stable iridium oxide (IrO x·nH2O) nanoparticle thin films from [Ir(OH) 6]2- solutions is reported. The [Ir(OH)6] 2- solution, made by alkaline hydrolysis of [IrCl6] 2-, is colorless and stable near neutral pH, and forms blue IrO x·nH2O nanoparticle suspensions once it is adjusted to acidic or basic conditions. IrOx·nH2O nanoparticle thin films are grown anodically on glassy carbon, fluorine-doped tin oxide, and gold electrodes by electrolyzing [Ir(OH)6] 2- solutions at +1.0-1.3 V versus Ag/AgCl. The thickness of the IrOx·nH2O films can be controlled by varying the concentration of [Ir(OH)6]2-, the deposition potential, and/or the deposition time. These thin films are stable between pH 1 and 13 and have the lowest overpotential (η) for the oxygen evolution reaction (OER) of any yet reported. Near neutral pH, the Tafel slope for the OER at a IrOx·nH2O film/Au rotating disk electrode was 37-39 mV per decade. The exchange current density for the OER was 4-8 × 10-10 A cm-2 at a 4 mC cm-2 coverage of electroactive Ir.
AB - A facile, in-situ deposition route to stable iridium oxide (IrO x·nH2O) nanoparticle thin films from [Ir(OH) 6]2- solutions is reported. The [Ir(OH)6] 2- solution, made by alkaline hydrolysis of [IrCl6] 2-, is colorless and stable near neutral pH, and forms blue IrO x·nH2O nanoparticle suspensions once it is adjusted to acidic or basic conditions. IrOx·nH2O nanoparticle thin films are grown anodically on glassy carbon, fluorine-doped tin oxide, and gold electrodes by electrolyzing [Ir(OH)6] 2- solutions at +1.0-1.3 V versus Ag/AgCl. The thickness of the IrOx·nH2O films can be controlled by varying the concentration of [Ir(OH)6]2-, the deposition potential, and/or the deposition time. These thin films are stable between pH 1 and 13 and have the lowest overpotential (η) for the oxygen evolution reaction (OER) of any yet reported. Near neutral pH, the Tafel slope for the OER at a IrOx·nH2O film/Au rotating disk electrode was 37-39 mV per decade. The exchange current density for the OER was 4-8 × 10-10 A cm-2 at a 4 mC cm-2 coverage of electroactive Ir.
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U2 - 10.1002/smll.201100485
DO - 10.1002/smll.201100485
M3 - Article
C2 - 21678551
AN - SCOPUS:79960349311
SN - 1613-6810
VL - 7
SP - 2087
EP - 2093
JO - Small
JF - Small
IS - 14
ER -