Article, 2023

Benchmarking the pH–Stability Relationship of Metal Oxide Anodes in Anion Exchange Membrane Water Electrolysis

ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Volume 11, 36, Pages 13251-13259, 10.1021/acssuschemeng.3c01619

Contributors

Zhang, Liyue [1] Xu, Qiucheng 0000-0002-2771-9643 (Corresponding author) [2] Hu, Yanjie 0000-0003-4531-8429 [1] Chen, Ling [1] Jiang, Hao 0000-0002-4388-6548 (Corresponding author) [1]

Affiliations

  1. [1] East China University of Science and Technology
  2. [NORA names: China; Asia, East];
  3. [2] Technical University of Denmark
  4. [NORA names: DTU Technical University of Denmark; University; Denmark; Europe, EU; Nordic; OECD]

Abstract

Anion exchange membrane water electrolysis (AEMWE) is one of the most promising technologies for producing green hydrogen; however, they still suffer from durability issues. One task is to find suitable electrolyte conditions for anode catalysts that endow them with both high activity and stability. Herein, we benchmark the pH–stability relationship of four typical metal oxides as anode catalysts in the AEMWE. Their electrochemical performance and structural stability were in-depth analyzed through impedance, dissolved composition in the electrolyte, and correlated Pourbaix diagram. NiFe2O4 with the best activity and stability in the strong alkaline (pH = 14) shows terrible stability in pure water, which is then verified due to the severe Fe leaching, and it cannot be alleviated by alkaline pre-activation. Notably, Co3O4 shows comparable activity and stability to IrO2 in pure water and weak alkaline conditions. At pH = 12, it entails only ∼2.18 V to reach 1.0 A cm–2 and stabilizes for 40 h, being superior to others. This work screens out suitable transition metal oxides as a substitute for noble metals and their optimal application scenarios for AEMWE.

Keywords

Co3O4, Fe leaching, IrO2, NiFe2O4, Pourbaix diagrams, activity, alkaline, alkaline conditions, anion exchange membrane water electrolysis, anions, anode, anode catalyst, application scenarios, catalyst, cm-2, composition, conditions, diagram, dissolver composition, durability, durability issues, electrochemical performance, electrolysis, electrolyte, electrolyte conditions, green hydrogen, hydrogen, impedance, issues, leaching, metal, metal oxide anodes, metal oxides, noble metals, optimal application scenarios, oxidation, oxide anodes, pH, pH stability, performance, pre-activation, relationship, scenarios, screening, stability, structural stability, task, technology, transition, transition metal oxides, water, water electrolysis, weak alkaline conditions

Funders

  • National Natural Science Foundation of China

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