Key Takeaways & Executive Findings
- •• Core–shell IrPt nanoalloy on La/Ni–Co3O4 achieves unprecedented bifunctional activity (2 A cm−2 at 1.72 V) in PEMWE with ultralow loadings (0.075 mg cm−2 Ir/Pt at both electrodes). • 646-h durability in PEMWE cell (5 μV h−1 decay) via IrPt-core@IrPtOx-shell synergy, hierarchical pores, and oxygen vacancies for robust electron/mass transfer and active-site stability. • In situ X-ray absorption spectroscopy combined with density functional theory unveils Ir–O–Pt sites enabling bi-nuclear oxygen evolution reaction and Volmer–Tafel hydrogen evolution reaction mechanisms through optimized Ir/Pt charge redistribution, breaking kinetic limitations. • This work provides a cost-effective solution for green hydrogen production and advances the design of high-performance bifunctional catalysts for PEMWE.
Abstract
The development of highly efficient and durable bifunctional catalysts with minimal precious metal usage is critical for advancing proton exchange membrane water electrolysis (PEMWE). We present an iridium–platinum nanoalloy (IrPt) supported on lanthanum and nickel co-doped cobalt oxide, featuring a core–shell architecture with an amorphous IrPtOx shell and an IrPt core. This catalyst exhibits exceptional bifunctional activity for oxygen and hydrogen evolution reactions in acidic media, achieving 2 A cm−2 at 1.72 V in a PEMWE device with ultralow loadings of 0.075 mgIr cm−2 and 0.075 mgPt cm−2 at anode and cathode, respectively. It demonstrates outstanding durability, sustaining water splitting for over 646 h with a degradation rate of only 5 μV h−1, outperforming state-of-the-art Ir-based catalysts. In situ X-ray absorption spectroscopy and density functional theory simulations reveal that the optimized charge redistribution between Ir and Pt, along with the IrPt core–IrPtOx shell structure, enhances performance. The Ir–O–Pt active sites enable a bi-nuclear mechanism for oxygen evolution reaction and a Volmer–Tafel mechanism for hydrogen evolution reaction, reducing kinetic barriers. Hierarchical porosity, abundant oxygen vacancies, and a high electrochemical surface area further improve electron and mass transfer. This work offers a cost-effective solution for green hydrogen production and advances the design of high-performance bifunctional catalysts for PEMWE.
1. Introduction
The transition to a sustainable energy future hinges on the development of efficient technologies for green hydrogen production, with proton exchange membrane water electrolysis (PEMWE) emerging as a leading candidate [1]. PEMWE offers a promising pathway to convert and store renewable energy, addressing the global energy crisis and advancing carbon neutrality goals [2–6]. However, the widespread adoption of PEMWE is hindered by the reliance on precious group metals (PGMs), such as platinum (Pt) and iridium (Ir), which are scarce, expensive, and subject to supply chain constraints [7]. Currently, Pt and Ir remain the materials of choice for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, due to their optimal balance of electrocatalytic activity and durability under the harsh acidic and corrosive conditions of PEMWE [8]. Nevertheless, typical Pt loadings at the cathode (~0.4 mg cm−2) and Ir loadings at the anode (2–4 mg cm−2) far exceed the U.S. Department of Energy (DOE) 2026 target of reducing total PGM loading to <0.5 mg cm−2 without compromising performance [9, 10].
The development of bifunctional catalysts capable of catalyzing both OER and HER has gained significant attention, as they simplify electrode manufacturing and reduce costs [11–15]. However, designing such catalysts with significantly reduced PGM loadings while maintaining high activity and stability remains a formidable challenge, particularly under the extreme chemical and electrochemical conditions of PEMWE [16, 17]. While Pt is the most effective HER catalyst, it performs poorly
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Yifei Liu, Xinmeng Er, Xinyao Wang, Hangxing Ren, Wenchao Wang, Feng Cao, Taiyan Zhang, Pan Liu, Yakun Yuan, Fangbo Yu, Yang Ren, Fuqiang Huang, Wenjiang Ding, Lina Chong (2025). Core–Shell IrPt Nanoalloy on La/Ni–Co3O4 for High-Performance Bifunctional PEM Electrolysis with Ultralow Noble Metal Loading. Nano-Micro Letters. https://doi.org/10.1007/s40820-025-01845-7
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Frequently Asked Questions
What is the main achievement of this study?
The study presents a core-shell IrPt nanoalloy on La/Ni-Co3O4 that achieves high-performance bifunctional PEM electrolysis with ultralow noble metal loadings (0.075 mg cm−2 Ir/Pt at both electrodes), reaching 2 A cm−2 at 1.72 V and sustaining over 646 hours with only 5 μV h−1 degradation.
How does the catalyst achieve high activity and durability?
The catalyst's core-shell structure (IrPt core with amorphous IrPtOx shell), hierarchical porosity, oxygen vacancies, and optimized charge redistribution between Ir and Pt enhance electron/mass transfer and active-site stability, enabling efficient bi-nuclear OER and Volmer-Tafel HER mechanisms.
What is the significance of the ultralow noble metal loading?
The ultralow loading (0.075 mg cm−2 Ir and Pt) significantly reduces the cost of PEM electrolyzers, addressing the DOE 2026 target of total PGM loading <0.5 mg cm−2, making green hydrogen production more economically viable.
What methods were used to investigate the catalyst?
The researchers used in situ X-ray absorption spectroscopy (XAS) and density functional theory (DFT) simulations to reveal the Ir–O–Pt active sites and the reaction mechanisms, along with electrochemical testing in a PEMWE device.
What are the practical implications of this work?
This work offers a cost-effective solution for green hydrogen production by reducing reliance on scarce and expensive precious metals, and provides a design strategy for high-performance bifunctional catalysts for PEMWE.
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