5f Covalency Synergistically Boosting Oxygen Evolution of UCoO₄ Catalyst

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Electronic structure modulation is crucial for efficient catalyst design.
• Research predominantly focuses on 3d transition metals, with limited exploration of f-block metals.
• The role of f-block elements in catalytic processes remains underexplored.

Purpose of the Study:

• To report a new class of catalyst, UCoO₄, incorporating f-block metal (uranium).
• To investigate the enhanced electrocatalytic oxygen evolution reaction (OER) activity of UCoO₄.
• To elucidate the mechanism behind the enhanced activity, focusing on the U 5f-O 2p-Co 3d network.

Main Methods:

• Synthesis and characterization of UCoO₄.
• Electrocatalytic testing for oxygen evolution reaction (OER).
• X-ray absorption spectroscopy (XAS) for elemental valence state analysis.
• Density functional theory (DFT) calculations for electronic structure and mechanism investigation.

Main Results:

• UCoO₄ exhibits enhanced OER activity with a low overpotential of 250 mV at 10 mA cm⁻².
• XAS revealed Co²⁺ oxidation to Co³⁺/⁴⁺, while U⁶⁺ remained unchanged during OER, identifying Co as the active site.
• DFT calculations confirmed synergistic enhancement of Co activity via U⁶⁺-5f covalent bonding in the U 5f-O 2p-Co 3d network.

Conclusions:

• UCoO₄ represents a novel 5f-covalent compound with superior OER performance compared to unitary cobalt catalysts.
• The study highlights the significant potential of f-block elements in catalyst design.
• This work opens new research avenues for electronic structure manipulation through 5f element involvement in catalysis.