Bicontinuous RuO₂ nanoreactors for acidic water oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Ruthenium (Ru)-based catalysts are explored as alternatives to expensive Iridium (Ir) for proton-exchange membrane water electrolyzers (PEMWEs).
• Improving the activity and stability of Ru catalysts in acidic media is crucial for practical PEMWE applications.

Purpose of the Study:

• To develop a novel bicontinuous nanoreactor of multiscale defective Ruthenium dioxide nanomonomers (MD-RuO2-BN).
• To enhance the water oxidation activity and long-term stability of Ru-based catalysts in acidic environments for PEMWEs.

Main Methods:

• Fabrication of a bicontinuous nanoreactor using multiscale defective RuO2 nanomonomers.
• Characterization using three-dimensional tomograph reconstruction technology.
• Electrochemical testing in acidic media and performance evaluation in a homemade PEMWE.
• Theoretical calculations and in-situ Raman spectroscopy for mechanistic studies.

Main Results:

• The MD-RuO2-BN structure exhibits abundant active sites and efficient mass transfer.
• Optimized electron and micro-structure led to high water oxidation activity (196 mV @ 10 mA cm-2) and ultralow degradation (1.2 mV h-1).
• A homemade PEMWE with MD-RuO2-BN anode showed excellent water splitting performance (1.64 V @ 1 A cm-2).

Conclusions:

• The bicontinuous nanoreactor design with multiscale defects synergistically enhances Ru catalyst performance.
• MD-RuO2-BN demonstrates superior activity and stability, making it a promising anode catalyst for PEMWEs.
• The study elucidates the mechanism behind the enhanced performance, driven by defect engineering and protected active sites.