Advancing Green Hydrogen Production: Synthesizing and Analyzing Nickel and Iron Micro-Flower Shaped Electrocatalysts on Ni-Mesh for Alkaline Water Electrolysis
Authors: Jaeger Rutha , Valk Peeter , Grozovski Vitali , Volobujeva Olga , Prits Alise-Valentine , Maide Martin , Küngas Rainer , Lust Enn , Nerut Jaak 
Published: December 2024

Hydrogen is essential for various uses in the fuel, chemical industry, and energy carriers industries. Global demand is set to double by 2030, reaching 180 Mt [1]. Currently, fossil fuels are the primary source of hydrogen production, which causes significant CO2 emissions [2]. Therefore, producing CO2-free, so-called green hydrogen by electrolysis of water is promising. Effective electrocatalysts are vital for implementing this strategy. However, the high cost and rarity of commonly used noble metal-based catalysts pose significant barriers to their realization [3].
Herein, we report electrocatalysts based on Ni and Fe synthesized onto Ni-mesh. As in the case of hydrothermal synthesis [4], the purified Ni mesh was autoclaved with a mixture of precursors at 100 oC for 8 h. For comparison, a series of catalysts with different molar ratios were prepared and electrodeposited Nix-FeyOOH catalyst was used.
The morphology and structure of the synthesized materials were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. Figure 1 displays a SEM image illustrating a three-dimensional micro-flower formation of Ni and Fe oxides, characteristic of the hydrothermal synthesis process [4,5].
The oxygen evolution reaction (OER) performance of synthesized catalysts was measured in 1 M KOH using a standard three-electrode setup at room temperature to demonstrate the efficiency of electrocatalysts. Additionally, bare Ni-mesh was included as a control sample for comparison.
However, electrode fabrication methods and techniques should be scalable and automated, allowing electrolyzer production volumes to be easily scaled to meet growing demand. Therefore, using the same methods, large surface area (20 cm2) Ni-mesh-based electrodes were prepared, and their OER activity was investigated in a 6 M KOH solution in an electrolysis cell (80 °C).

Acknowledgements

This work was supported by the Estonian Research Council (Proof-of-Concept Grant EAG273), the University of Tartu (Experimental Development Grant Novel Catalysts for Alkaline Electrolyser Electrodes Based on Nickel Foam) and the Estonian Ministry of Education and Research (Center of Excellence TK210).

References:
[1] J.M. Bermudez, S. Evangelopoulou, F. Pavan, Hydrogen, Int. Energy Agency (2024). https://www.iea.org/energy-system/low-emission-fuels/hydrogen (accessed February 12, 2024).
[2] Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. A hydrogen strategy for a climate-neutral Europe, 2020. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52020DC0301 (accessed February 12, 2024).
[3] C. Zhang, Y. Xie, H. Deng, C. Zhang, J.-W. Su, Y. Dong, J. Lin, Int. J. Hydrogen Energy, 43 (2018) 7299.
[4] J. Yu, G. Cheng, W. Luo, J. Mater. Chem. A, 5 (2017) 15838.
[5] J. Xu, Z. Liu, Z. Wei, S. Zhang, C. Guo, M. He, Electrochimica Acta, 348 (2020) 136417.

Figure 1