2023 AIChE Annual Meeting

(222b) Non-Precious Electrodes Design for Hydroxide Exchange Membrane Electrolyzers

Authors

Xiao, F. - Presenter, University of Delaware
Oliveira, A., University of Connecticut
Setzler, B. P., Georgia Institute of Technology
Shao, M., The Hong Kong University of Science and Technology
Yan, Y., University of Delaware
Hydrogen is an excellent energy carrier to replace fossil fuels with renewable energy and the green hydrogen generated by electrolysis is the cleanest candidate.1-2 Department of Energy in the United States has set "1 dollar ($) per kilogram (kg) in one-decade" cost and 80-thousand-hour durability targets for clean hydrogen production. The current price of green hydrogen (5-6 $/kg) must be lowered by reducing electricity and electrocatalyst expense. The increased capacity of renewable energy leads to a significant price reduction in electricity.3 The next task is to cheapen the material cost of catalysts. Because various non-precious metal materials and components are stable in high pH environments, hydroxide exchange membrane electrolyzers (HEMELs) can use non-precious metal catalysts in both electrodes. However, the weakly adhered catalyst layers in HEMELs always suffer from continuous gas generation and bubble detachment disturbance, resulting in a short lifespan.

Herein, we report a work about a novel cathodic electrode preparation technique to improve the activity and durability of non-precious metal based HEMELs. Propylene glycol is added into the conventional water and alcohol solvent system to enhance the adherence among Ni-Mo/Engineered catalyst support catalyst (purchased from Pajarito Powder company) agglomerates. An additional carbon layer configuration is designed between the gas diffusion and catalyst layers to alleviate wash-off and transfer-to-membrane issues during tests. This HEMEL with Ni-Fe-OOH anode4 and Ni-Mo/Engineered catalyst support cathode can achieve a 500 mA cm-2 current density at 1.8 V under pure water. The optimized electrode structure can prevent the detachment of catalysts during continuous operation and demonstrate good voltage stability at 200 mA cm-2 current density for above 100 h. The role of propylene glycol in the catalyst-ink formulation and the contribution of the additional carbon layer to water/gas transport efficiency will be systematically explored. This work highlights the importance of electrode design for achieving highly active and stable non-precious metal based HEMELs, and sheds light on developing advanced electrode structures for other electrochemical devices.

  1. Oliveira, A. M.; Beswick, R. R.; Yan, Y., Current Opinion in Chemical Engineering 2021, 33, 100701.
  2. Abbasi, R.; Setzler, B. P.; Lin, S.; Wang, J.; Zhao, Y.; Xu, H.; Pivovar, B.; Tian, B.; Chen, X.; Wu, G.; Yan, Y., Advanced Materials 2019, 31 (31), 1805876.
  3. Pivovar, B.; Rustagi, N.; Satyapal, S., The Electrochemical Society Interface 2018, 27 (1), 47.
  4. Xiao, J.; Oliveira, A. M.; Wang, L.; Zhao, Y.; Wang, T.; Wang, J.; Setzler, B. P.; Yan, Y., ACS Catalysis 2021, 11 (1), 264-270.