Modulating the atomic local structure of ruthenium oxide for enhanced oxygen evolution reaction.
image: The atomic-scale local structures of ruthenium oxide were precisely engineered through controllable manipulation of oxygen vacancies (Ov) via high-vacuum annealing. The optimized Ru-Ru and adjacent Ru-O centers synergistically activate the oxide pathway mechanism and minimize the structural distortion during the OER, thereby synergistically enhancing both OER activity and stability.
Credit: Nano Research, Tsinghua University Press
A research team led by Professor Wenping Sun from Zhejiang University has developed an innovative high-vacuum annealing strategy to precisely control oxygen vacancy (Ov) concentrations in RuO2, achieving atomic-level modulation of local coordination structures. Their optimized RuO2–x catalyst demonstrates exceptional oxygen evolution reaction (OER) performance through synergistic effects between stable metallic Ru-Ru bonds and oxidized Ru-O moieties. This work addresses the longstanding challenge of balancing activity and stability in RuO2-based acidic OER electrocatalysts. While RuO2 exhibits superior catalytic activity compared to benchmark IrO2, its practical application has been limited by Ru dissolution and lattice oxygen overoxidation under acidic conditions.
The team published their paper in Nano Research on July 31, 2025.
The team achieved precise control of RuO2's atomic coordination environment by strategically introducing Ov sites through high-vacuum annealing, which subsequently induced the formation of metallic Ru clusters within the RuO2 matrix. Comprehensive characterization using X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) revealed that the engineered Ov sites simultaneously promoted Ru-Ru metallic interactions while maintaining critical Ru-O coordination.
The optimally modified RuO2-x-2 catalyst exhibited remarkable electrochemical performance, requiring only 169 mV overpotential to reach 10 mA cm–2 current density while demonstrating unprecedented stability—maintaining activity for over 400 hours in 0.5 M H2SO4. "Our catalyst surpasses most reported RuO2-based acidic OER electrocatalysts in both activity and durability," the authors noted.
Through advanced operando techniques including XAFS and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, the team uncovered the origin of the enhanced performance. The coexistence of metallic Ru-Ru and oxidized Ru-O sites created a synergistic system that activated the oxide pathway mechanism, effectively bypassing conventional scaling relationships and minimizing structural distortion during OER.
This work not only presents a practical strategy for coordination environment engineering in oxide catalysts but also provides fundamental insights into the design principles for robust, high-performance OER electrocatalysts. The findings pave the way for developing cost-effective alternatives to precious metal catalysts in proton exchange membrane water electrolyzers.
Other contributors include Bei Yang, Xiaozhong Zheng, Xiao Jin, Wei Guo, Mingxia Gao and Hongge Pan from the School of Materials Science and Engineering at Zhejiang University in Hangzhou, China; and Guoqiang Zhao from the Faculty of Materials Science and Chemistry at China University of Geosciences in Wuhan, China.
This research was financially supported by the National Natural Science Foundation of China (No. 92261119, 52301293). The researches also thanked beamline BL11B and BL14W1 of the Shanghai Synchrotron Radiation Facility (SSRF) and the Infrared spectroscopy experimental station (BL01B) in the National Synchrotron Radiation Laboratory (NSRL) for their support in XAFS and ATR-FTIR measurements.
About the Authors
Dr. Wenping Sun is a Professor at the School of Materials Science and Engineering, Zhejiang University. His research interests focus on electrochemical energy materials and devices (including fuel cells, water electrolysis for hydrogen production, metal-ion batteries, and hydrogen storage systems), as well as metal-based catalytic materials. He has published over 100 peer-reviewed articles in high-impact journals such as Nat. Catal., Adv. Mater., Nature Commun., Angew. Chem., Int. Ed., Adv. Funct. Mater., and Energy Environ. Sci.. These publications have garnered more than 23,000 citations, with an H-index of 84 according to Google Scholar metrics. For more information, please pay attention to his research homepage https://person.zju.edu.cn/wenpingsun.
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.