Pentavalent Uranium-Regulated U-Co-Ru Ternary Oxide: High-Efficient Electrocatalyst for Water Splitting

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Ruthenium dioxide (RuO2) is a key catalyst for water electrolysis but suffers from instability due to hypervalent ruthenium species.
• Catalyst inactivation during the oxidation process limits the efficiency and longevity of water splitting technologies.

Purpose of the Study:

• To develop a stable and highly active ternary oxide catalyst for water splitting.
• To investigate the role of uranium and cobalt doping in enhancing catalytic performance.
• To elucidate the mechanism of pentavalent uranium in oxygen evolution reactions.

Main Methods:

• Synthesis of a pentavalent uranium-regulated U-Co-Ru ternary oxide.
• Electrochemical testing in acidic, alkaline, and seawater media.
• In situ X-ray absorption fine structure (XAFS) analysis to study electronic and structural evolution.

Main Results:

• The U-Co-Ru ternary oxide exhibited significantly enhanced activity for water splitting across diverse environments.
• Exceptional performance in alkaline oxygen evolution reaction (OER) with low overpotentials (257 mV at 100 mA cm-2 and 366 mV at 1 A cm-2).
• In situ XAFS revealed that uranium sites act as interatomic springs, facilitating electron transfer via dynamic U-O bond adjustments and valence state changes.

Conclusions:

• The U-Co-Ru ternary oxide offers a stable and highly active alternative to traditional RuO2 catalysts.
• Dual doping with uranium and cobalt effectively modulates valence states and coordination, improving catalytic efficiency.
• This research provides a novel application for depleted uranium and offers the first in-depth understanding of pentavalent uranium's role in OER.