Efficient and sustainable water electrolysis achieved by excess electron reservoir enabling charge replenishment to catalysts.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37669945.
- Also identified by DOI 10.1038/s41467-023-41102-2 and PMC identifier 10480199.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Suppressing the oxidation of active-Ir(III) in IrO<sub>x</sub> catalysts is highly desirable to realize an efficient and durable oxygen evolution reaction in water electrolysis. Although charge replenishment from supports can be effective in preventing the oxidation of IrO<sub>x</sub> catalysts, most supports have inherently limited charge transfer capability. Here, we demonstrate that an excess electron reservoir, which is a charged oxygen species, incorporated in antimony-doped tin oxide supports can effectively control the Ir oxidation states by boosting the charge donations to IrO<sub>x</sub> catalysts. Both computational and experimental analyses reveal that the promoted charge transfer driven by excess electron reservoir is the key parameter for stabilizing the active-Ir(III) in IrO<sub>x</sub> catalysts. When used in a polymer electrolyte membrane water electrolyzer, Ir catalyst on excess electron reservoir incorporated support exhibited 75 times higher mass activity than commercial nanoparticle-based catalysts and outstanding long-term stability for 250 h with a marginal degradation under a water-splitting current of 1 A cm<sup>-2</sup>. Moreover, Ir-specific power (74.8 kW g<sup>-1</sup>) indicates its remarkable potential for realizing gigawatt-scale H<sub>2</sub> production for the first time.