Assembled RhRuFe Trimetallene for Water Electrolysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Industrial water electrolyzers require highly stable and active electrocatalysts for the oxygen evolution reaction (OER).
• Current iridium (Ir) or ruthenium (Ru)-based nanomaterials exhibit insufficient stability, driving the search for alternatives.
• Rhodium (Rh)-based materials are stable but moderately active, necessitating structural engineering for improved performance.

Purpose of the Study:

• To engineer Rh-based electrocatalysts for enhanced overall water splitting catalysis.
• To investigate the synergistic effects of alloying Rh with Ru and Fe in trimetallene nanostructures.
• To develop a bifunctional catalyst for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER).

Main Methods:

• Precise synthesis of assembled RhRuFe trimetallenes (RhRuFe TMs) with an average thickness of 1 nm.
• Electrocatalytic performance evaluation for OER and HER in water splitting devices.
• Analysis of electronic structure and binding energies of intermediates (H* and OH*) to understand catalytic mechanisms.

Main Results:

• RhRuFe TMs demonstrated significantly improved OER activity, requiring an overpotential of 330 mV to reach 10 mA cm⁻², a 601 mV improvement over Rh/C.
• Water splitting devices using RhRuFe TMs achieved 10 mA cm⁻² at a low voltage of 1.63 V, positioning them among the best Rh-based bifunctional catalysts.
• Iron (Fe) addition modulated strain and electron distribution, optimizing binding energies for enhanced bifunctional OER and HER catalysis.

Conclusions:

• Assembled RhRuFe trimetallenes represent a highly effective strategy for upgrading Rh-based electrocatalysts.
• The developed trimetallenes offer superior OER activity and bifunctional performance for overall water splitting.
• This work paves the way for more efficient and stable electrocatalysts in industrial water electrolysis.