Support-Intensified Ir─P/O─Mo Cooperative Linkages for Robust Acidic Water Dissociation

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Acidic water electrolysis for hydrogen production faces challenges due to slow oxygen evolution reaction (OER) kinetics and limited availability of stable bifunctional catalysts.
• Iridium-based materials show promise for OER and hydrogen evolution reaction (HER), but require improved atomic utilization and durability.

Purpose of the Study:

• To design and synthesize a support-intensified iridium catalyst with enhanced bifunctional activity and stability for acidic water electrolysis.
• To investigate the role of interfacial bond engineering, specifically Ir-P-Mo and Ir-O-Mo linkages, in optimizing catalytic performance.

Main Methods:

• Theoretical calculations were employed to understand the influence of different interfacial bonds (Ir-P-Mo and Ir-O-Mo) on HER and OER activity.
• A novel catalyst featuring coexisting Ir-O-Mo and Ir-P-Mo linkages was rationally synthesized.
• Electrochemical performance was evaluated using overpotential measurements for HER and OER at a current density of 10 mA cm⁻².

Main Results:

• The synthesized catalyst exhibited low overpotentials: 33 mV for HER and 249 mV for OER at 10 mA cm⁻².
• In a symmetrical two-electrode electrolyzer, the catalyst achieved 10 mA cm⁻² at a cell voltage of 1.501 V.
• The catalyst demonstrated remarkable stability, operating for 250 hours with minimal voltage degradation.

Conclusions:

• Interfacial bond engineering is crucial for developing efficient and durable iridium-based electrocatalysts for acidic water splitting.
• The designed catalyst with Ir-P-Mo and Ir-O-Mo linkages offers exceptional bifunctional performance and stability, paving the way for practical hydrogen production.