(584i) Insights into Long-Term Performance of Nickel-Based Oxygen Evolution Reaction Catalysts

Green H₂ plays a key role in the sustainability transition: it can be used as a renewable fuel, chemical building block, or an energy storage vector. Water electrolysis, powered by renewable energy, is currently the most promising method for green H₂ production on an industrially relevant scale(1). Among different types of electrolysis, alkaline reactors hold the promise of enabling the use of low-cost anion exchange membranes and abundant catalysts such as Nickel, yet the energy efficiency and stability of those catalysts are too low to make green H₂ economically competitive(2).Through chronoamperometry analysis, we identify and optimize the regimes in which crystal nuclei formation and growth occur. As a result, we achieved better controllability of the electrodeposition process and a significant increase in the current density of the OER catalyst. Using 1M KOH solution, a milder concentration than what is currently used in the industry (5-10 M KOH), we achieved 167 mA/cm² at 1.6V applied against an Ag/AgCl electrode. Previous literature reports on Ni-based catalysts reported max. 100 mA/cm² with the same energy efficiency(4,5), confirming that our nucleation control strategy can significantly enhance the electrocatalytic performance. Here, we report an abundant, cheap, energy-efficient, and stable Ni/NiFe catalyst for alkaline water splitting synthesized in a “Hybrid Electrode” electrochemical system. To increase the electroplating efficiency for the challenging OER reaction, we hypothesized that by carefully controlling the nucleation mechanism(3), we could achieve a more uniform deposition of the target co-catalyst resulting in a higher current density at lower overpotentials.

1. Shiva Kumar, S.; Lim, H. Energy Reports 2022, 8, 13793–13813
2. Du et al. Chemical Reviews 2022, 122 (13), 11830–11895
3. Tan et al. Journal of Colloid and Interface Science 2021, 600, 492–502
4. Lu and Zhao. Nat Commun 2015, 6, 6616
5. Zhang and Zou. Small 2021, 17 (37), 2100129