2 research outputs found
Synthesis and Demonstration of Subnanometric Iridium Oxide as Highly Efficient and Robust Water Oxidation Catalyst
Development
of a highly efficient and robust water oxidation catalyst
(WOC) with reduced usage of noble metals is extremely crucial for
water splitting and CO<sub>2</sub> reduction by photocatalysis or
electrolysis. Herein, we synthesized subnanometric iridium dioxide
clusters supported on multiwalled carbon nanotubes (MWCNTs) by a chemical
vapor deposition method (nominated as IrO<sub>2</sub>/CNT). Benefiting
from a mild oxidation process in air at 303 K, the deposited iridium
clusters can be controlled to have a narrow size distribution from
several atoms to 2 nm, having an average size of ca. 1.1 nm. The subnanometric
iridium-containing sample is demonstrated to be highly efficient and
robust for water oxidation. The optimal turnover frequency (TOF) of
chemical water oxidation on the as-obtained sample can reach 11.2
s<sup>–1</sup>, and the overpotential of electrochemical water
oxidation is 249, and 293 mV at 10 mA cm<sup>–2</sup> in 1.0
M KOH (pH: 13.6), and 0.5 M H<sub>2</sub>SO<sub>4</sub> (pH: 0), respectively.
On the basis of the structural characterizations and theory simulation,
the extraordinary performances of the ultrasmall iridium dioxide are
proposed to mainly originate from enhanced number of unsaturated surface
Ir atoms and change of local coordination environment. Our work highlights
the importance of subnanometric size of iridium dioxide in water oxidation