Rational Design of β-MnO2 via Ir/Ru Co-substitution for Enhanced Oxygen Evolution Reaction in Acidic Media

IF 11.3 1区化学 Q1 CHEMISTRY, PHYSICAL

ACS Catalysis Pub Date : 2025-01-17 DOI:10.1021/acscatal.4c05989

Runxu Deng, Feng Liu, Shixin Gao, Zhenwei Xia, Runjie Wu, Jincheng Kong, Jin Yang, Jiahao Wen, Xiao Zhang, Chade Lv, Yuhao Wang, Xiaoguang Li, Zheng Wang

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引用次数: 0

Abstract

The efficiency of the oxygen evolution reaction (OER) in acidic media is severely limited by the poor stability, low activity, and high cost of available catalysts. Enhancing intrinsic activity while maintaining stability and reducing reliance on precious metals is crucial. The typical adsorbate evolution mechanism (AEM) leads to high overpotentials and low activity, making the transition to alternative mechanisms, such as the lattice oxygen mechanism (LOM) or oxide path mechanism (OPM), highly desirable due to their lower overpotentials. Here, we combine density functional theory (DFT) calculations with experimental validation to enhance the activity and stability of β-MnO₂ via co-substitution with ruthenium (Ru) and iridium (Ir), enabling the transition from AEM to OPM. DFT calculations reveal that AEM is hindered by the weak nucleophilicity of water, while LOM suffers from high kinetic barriers due to structural distortions. In contrast, OPM demonstrates a significantly lower kinetic barrier, facilitated by the synergistic interaction between Ru and Ir. Experimentally, IrRuMnO_x was synthesized through co-precipitation and hydrothermal methods, showing an 80-fold improvement in mass activity and a 96-fold increase in stability compared to commercial IrO₂, with minimal noble metal leaching, as confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES). IrRuMnO_x exhibited an ultralow overpotential of 475 mV at 1 A·cm^–2 and a Tafel slope of 44.26 mV·dec^–1 in 0.5 M H₂SO₄, maintaining stable performance for over 100 h. Moreover, the IrRuMnO_x-based membrane electrode, with a low Ir loading of 0.075 mg_Ir·cm^–2, achieved remarkable current densities of 1.0 A·cm^–2 at 1.66 V and 2.0 A·cm^–2 at 1.91 V at 80 °C. This performance surpasses that of both unsupported and conventional supported Ir-based catalysts at comparable Ir loading levels. This study offers critical insights into OER mechanisms in acidic media and paves the way for developing efficient and durable OER electrocatalysts for hydrogen production.

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来源期刊

ACS Catalysis CHEMISTRY, PHYSICAL-

CiteScore

20.80

自引率

6.20%

发文量

1253

审稿时长

1.5 months

期刊介绍： ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels. The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.