Cr dopant mediates hydroxyl spillover on RuO<sub>2</sub> for high-efficiency proton exchange membrane electrolysis.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39251585.
- Also identified by DOI 10.1038/s41467-024-51871-z and PMC identifier 11385839.
- Licence recorded as CC BY-NC-ND.
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Abstract
Simultaneously improving the activity and stability of catalysts for anodic oxygen evolution reaction (OER) in proton exchange membrane water electrolysis (PEMWE) remains a notable challenge. Here, we report a chromium-doped ruthenium dioxide with oxygen vacancies, termed Cr<sub>0.2</sub>Ru<sub>0.8</sub>O<sub>2-x</sub>, that drives OER with an overpotential of 170 mV at 10 mA cm<sup>-2</sup> and operates stably over 2000 h in acidic media. Experimental and theoretical studies show that the synergy of Cr dopant and oxygen vacancy induces an unconventional dopant-mediated hydroxyl spillover mechanism. Such dynamic hydroxyl spillover from Cr dopant to Ru active site changes the rate-determining step from OOH* formation to O<sub>2</sub> formation and thus greatly improves the OER performance. Moreover, the Cr dopant and oxygen vacancy also play a crucial role in stabilizing surface Ru and lattice oxygen in the Ru-O-Cr structural motif. When assembled into the anode of a practical PEMWE device, Cr<sub>0.2</sub>Ru<sub>0.8</sub>O<sub>2-x</sub> enables long-term durability of over 200 h at an ampere-level current density and 60 degrees centigrade.