Enhanced Durability of Nickel-Based Electrocatalysts for Oxygen Evolution Reaction (OER) at High Current Densities Using External Stimulation

Abstract

Hydrogen (H2) is one of the most promising energy carriers for future clean energy production. The cleanest method to produce H2 is by water electrolysis using renewable electricity. Among electrolysis technologies, alkaline water electrolysis (AWE) is significantly cheaper than other techniques. While AWE is cost effective, it suffers from low power densities due to limited electrochemical stability at high current densities. Most stability challenges arise from anode degradation, where the oxygen evolution reaction (OER) occurs. The OER is key to achieve economic viability of AWE and current state-of-the-art electrocatalysts for OER are costly and scarce. Nickel-based catalysts are inexpensive, earth-abundant, and exhibit high OER performance but still exhibit durability challenges under high current densities. While several approaches have been reported to enhance durability of these catalysts, they are often complicated and time-consuming. We present a novel and simple method through which external stimulation can be used to enhance the durability of single metal catalysts. In this work, the durability of nickel-based electrocatalysts for OER under alkaline conditions (1 M NaOH) at high current densities was evaluated as a function of external stimulation in a chemically stable custom electrochemical cell. This cell was fabricated using additive manufacturing (AM), which enabled the direct application of external stimulation onto nickel-based materials in the cell. In addition, the performance of the electrocatalysts at high OER current densities for extended periods of time was measured as a function of various external stimulation parameters. Acknowledgements Financial support from the Los Alamos National Laboratory, Laboratory-Directed Research and Development (LDRD) is gratefully acknowledged. The authors would also like to thank the NNSA Minority Serving Institutes Partnership Program and LANL: Under-Represented Minority Partnership Program for their funding support. References Vij, Varun, et al. "Nickel-based electrocatalysts for energy-related applications: oxygen reduction, oxygen evolution, and hydrogen evolution reactions." Acs Catalysis10 (2017): 7196-7225.Foroughi, Faranak, et al. "Understanding the Effects of Ultrasound (408 kHz) on the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) on Raney-Ni in Alkaline Media." Ultrasonics Sonochemistry 84 (2022): 105979.Foroughi, Faranak, et al. "Sonoactivated polycrystalline Ni electrodes for alkaline oxygen evolution reaction." Ultrasonics Sonochemistry 86 (2022): 106013.