Engineering metal-oxide interfaces via controlled exsolution in Ir-doped Y₂Ru₂O₇ pyrochlore for superior hydrogen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient and durable electrocatalysts for the hydrogen evolution reaction (HER) is critical for sustainable energy technologies.
• Pyrochlore oxides offer structural versatility but face limitations in HER due to weak hydrogen binding, poor conductivity, and limited active site exposure.

Purpose of the Study:

• To create optimized RuIr/Y2O3 heterointerfaces from Ir-doped Y2Ru2O7 pyrochlore oxide using controlled in-situ exsolution.
• To enhance charge transfer properties and HER performance through precise control over exsolved nanoparticle size and distribution.

Main Methods:

• Controlled in-situ exsolution of RuIr nanoparticles from an Ir-doped Y2Ru2O7 pyrochlore oxide precursor.
• Systematic tuning of reduction parameters (temperature and time) to control nanoparticle characteristics.
• Advanced characterization techniques and Density Functional Theory (DFT) calculations to investigate catalytic mechanisms.

Main Results:

• Optimized RuIr/Y2O3 heterointerfaces (YRIO-450-8H) were successfully synthesized.
• The catalyst demonstrated exceptional HER performance, requiring low overpotentials (20 mV in alkaline, 30 mV in acidic) to achieve 10 mA cm-2, surpassing commercial Pt/C.
• Long-term stability was observed over 120 hours in alkaline and 55 hours in acidic media.

Conclusions:

• The enhanced HER activity is attributed to synergistic effects, including optimized hydrogen binding energy at RuIr sites, modulated electronic structure at the metal-oxide interface, and abundant oxygen vacancies.
• The study provides fundamental insights into exsolution mechanisms and design principles for advanced heterogeneous electrocatalysts.