1 research outputs found
IrO<sub>2</sub>āTiO<sub>2</sub>: A High-Surface-Area, Active, and Stable Electrocatalyst for the Oxygen Evolution Reaction
The
utilization and development of efficient water electrolyzers
for hydrogen production is currently limited due to the sluggish kinetics
of the anodic processīøthe oxygen evolution reaction (OER).
Moreover, state of the art OER catalysts contain high amounts of expensive
and low-abundance noble metals such as Ru and Ir, limiting their large-scale
industrial utilization. Therefore, the development of low-cost, highly
active, and stable OER catalysts is a key requirement toward the implementation
of a hydrogen-based economy. We have developed a synthetic approach
to high-surface-area chlorine-free iridium oxide nanoparticles dispersed
in titania (IrO<sub>2</sub>-TiO<sub>2</sub>), which is a highly active
and stable OER catalyst in acidic media. IrO<sub>2</sub>-TiO<sub>2</sub> was prepared in one step in molten NaNO<sub>3</sub> (Adams fusion
method) and consists of ca. 1ā2 nm IrO<sub>2</sub> particles
distributed in a matrix of titania nanoparticles with an overall surface
area of 245 m<sup>2</sup> g<sup>ā1</sup>. This material contains
40 mol<sub>M</sub> % of iridium and demonstrates improved OER activity
and stability in comparison to the commercial benchmark catalyst and
state of the art high-surface-area IrO<sub>2</sub>. Ex situ characterization
of the catalyst indicates the presence of iridium hydroxo surface
species, which were previously associated with the high OER activity.
Operando X-ray absorption studies demonstrate the evolution of the
surface species as a function of the applied potential, suggesting
the conversion of the initial hydroxo surface layer to the oxo-terminated
surface via anodic oxidation (OER regime)