In situ Electrochemical Characterization Techniques for Active Hydrogen in Electrocatalytic Nitrate Reduction to Ammonia

Authors

• Hong-Mei Li, College of Chemistry, Sichuan University, Chengdu 610065, P. R. China
• Mei Yi, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, P. R. China
• Zhao-Yu Jin, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, P. R. China
• Ming-Hao Xie, Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
• Khalid M. Omer, Department of Chemistry, College of Science, University of Sulaimani, Sulaimani City, Kurdistan Region 46002, Iraq
• Yong Guo, College of Chemistry, Sichuan University, Chengdu 610065, P. R. ChinaFollow
• Pan-Pan Li, College of Materials Science and Engineering, Sichuan University, Chengdu 610065, P. R. ChinaFollow

Corresponding Author

Yong Guo ([email protected]);
Pan-Pan Li ([email protected])

Abstract

Electrocatalytic nitrate reduction to ammonia (NitRR) represents a sustainable pathway that integrates environmental remediation with the production of high-value ammonia. However, the activity and selectivity of this process are limited by the generation, consumption, and dynamic equilibrium of the key transient intermediate—active hydrogen (*H). Precise modulation of *H necessitates a comprehensive understanding of its behavior, which relies fundamentally on advanced in situ electrochemical characterization techniques. However, a systematic review dedicated to the rational selection and application of in situ electrochemical techniques for the specific characterization of *H in NitRR, with clear definitions of each technique's "detectable targets, quantitative accuracy, and application boundaries" remains absent. This review aims to fill this methodological gap by systematically summarizing in situ electrochemical techniques for probing *H behavior in NitRR, including in situ spectroscopic techniques, in situ electrochemical methods, and scanning electrochemical microscopy. We construct a problem-oriented hierarchical methodological framework tailored for *H characterization in NitRR. By detailing the principles, representative applications, and limitations of these techniques, this review provides a reliable guide for selecting appropriate characterization methods in future *H research, thereby deepening the mechanistic understanding of NitRR. Additionally, future research directions and development trends are discussed, offering insights to advance efficient and selective green ammonia synthesis techologies.

Graphical Abstract

Keywords

Nitrate reduction reaction, Active hydrogen, In situ electrochemical characterization technique, Ammonia electrosynthesis

DOI Link

https://doi.org/10.61558/2993-074X.3619

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Publication Date

2026-08-28

Online Available Date

2026-06-11

Revised Date

2026-05-05

Received Date

2026-03-25

Recommended Citation

Hong-Mei Li, Mei Yi, Zhao-Yu Jin, Ming-Hao Xie, Khalid M. Omer, Yong Guo, Pan-Pan Li. In situ Electrochemical Characterization Techniques for Active Hydrogen in Electrocatalytic Nitrate Reduction to Ammonia[J]. Journal of Electrochemistry, 2026, 32(8): 2517003.
DOI: 10.61558/2993-074X.3619
Available at: https://jelectrochem.xmu.edu.cn/journal/vol32/iss8/1