Metallic Ru─Ru Interaction in Ruthenium Oxide Enabling Durable Proton Exchange Membrane Water Electrolysis.
basic_science · Level V
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- Record sourced from PubMed, PMID 38695334.
- Also identified by DOI 10.1002/adma.202404213.
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Abstract
Developing efficient and robust electrocatalysts toward the oxygen evolution reaction (OER) is critical for proton exchange membrane water electrolysis (PEMWE). RuO<sub>2</sub> possesses intrinsically high OER activity, but the concurrent electrochemical dissolution leads to rapid deactivation. Here a unique RuO<sub>2</sub> catalyst containing metallic Ru─Ru interactions (m-RuO<sub>2</sub>) is reported, which maintains stability in practical PEMWE for 100 h at 60 °C and 1 A cm<sup>-2</sup>. Experimental and theoretical investigations suggest that the presence of Ru─Ru interactions significantly increases the energy barrier for the formation of RuO<sub>2</sub>(OH)<sub>2</sub>, which is a key intermediate for Ru dissolution, and hence substantially mitigates the electrochemical corrosion of m-RuO<sub>2</sub>. Meanwhile, the Ru4d band center downshifts, accordingly, ensuring the high OER activity, and the participation of lattice oxygen in the OER is also suppressed at the Ru─Ru sites, further contributing to the enhanced durability. Interestingly, such enhanced stability is also dependent on the size of metallic Ru─Ru cluster, where the energy barrier is further increased for Ru<sub>3</sub>, but is decreased for Ru<sub>5</sub>. These results highlight the significance of local coordination structure modulation on the electrochemical stability of RuO<sub>2</sub> and open a feasible avenue toward the development of robust OER electrocatalysts for high-performance PEMWE.