Ultrathin Iridium Nanosheets on Titanium Oxide for High-Efficiency and Durable Proton Exchange Membrane Water Electrolysis.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41369280.
- Also identified by DOI 10.1021/acsnano.5c15659 and PMC identifier 12752681.
- Licence recorded as CC BY-NC-ND.
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Abstract
Reducing iridium (Ir) usage is essential for the commercial viability of proton exchange membrane water electrolysis (PEMWE), where the oxygen evolution reaction (OER) is a major performance and cost bottleneck. Conventional Ir nanoparticles (∼5 nm) suffer from low dispersion and limited surface utilization. Here, we report a catalyst architecture comprising ultrathin Ir nanosheets (Ir NS) supported on spherical TiO<sub>2</sub> particles (Ir NS/TiO<sub>2</sub>). The ∼100 nm TiO<sub>2</sub> particles effectively disperses 1-3 μm-wide, sub 2 nm-thick Ir nanosheets, ensuring full surface exposure and continuous electron transport, despite the intrinsically low conductivity of TiO<sub>2</sub>. The Ir NS/TiO<sub>2</sub> catalyst exhibits enhanced OER activity and durability in both half-cell and PEMWE single-cell configurations. At an Ir loading of 0.7 mg<sub>Ir</sub> cm<sup>-2</sup>, Ir NS/TiO<sub>2</sub> achieves 3.6 A cm<sup>-2</sup> at 1.8 V, significantly outperforming commercial Ir nanoparticles (Ir NP, 2.6 A cm<sup>-2</sup>). Long-term operation at 1.0 A cm<sup>-2</sup> over 1000 h shows a low voltage decay rate of 0.095 mV h<sup>-1</sup>, compared to 0.414 mV h<sup>-1</sup> for Ir NP. Moreover, Ir NS/TiO<sub>2</sub> with an Ir loading amount of 0.5 mg<sub>Ir</sub> cm<sup>-2</sup> delivers comparable performance to Ir NP at 1.4 mg<sub>Ir</sub> cm<sup>-2</sup>. These results present Ir NS/TiO<sub>2</sub> as a highly efficient and durable OER catalyst, supporting its potential for cost-effective, scalable green hydrogen production.