(136b) Effect of Mn and Fe on Nicomo Electrocatalytic Performance for Seawater Electrolysis for Hydrogen Production

Electrocatalysts are essential for reducing overpotentials in water electrolysis, enhancing the efficiency of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). While precious metal catalysts based on Pt, Ru and Ir demonstrate excellent performance, their high cost has prompted research into non-precious metal-based high-entropy alloys (HEAs) as cost-effective alternatives [1]. HEAs synthesized with elements such as Ni, Co, Mo, Mn, and Cr have shown promising catalytic activity [2]; however, further improvements are required to optimize their performance. We hypothesize that the addition of specific metal elements can enhance the catalytic properties of HEAs through tailored electronic and structural effects.

In this study, we synthesized NiCoMoFeP and NiCoMoMnP HEAs using an electroless encapsulation technique. The alloys were deposited onto conductive, porous, and free-standing carbon cloth activated with palladium. The catalytic performance of NiCoMoFeP and NiCoMoMnP as bifunctional electrocatalysts for both OER and HER in seawater was compared to NiCoMoP, revealing significant variations in catalytic activity. For OER, the addition of Mn reduced the overpotential while no difference was found with the addition of Fe to NiCoMoP, while for the HER both the addition of Fe and Mn lowered the overpotential to 129 mV relative to a value of 203 V obtained for the NiCoMoP electrocatalyst. The findings demonstrate the potential of tailored HEAs to enhance electrolysis efficiency, contributing to the development of cost-effective green hydrogen production.

REFERENCES

[1] M. M. Hasan, A. K. Gomaa, G. E. Khedr, K. E. Salem, B. S. Shaheen, and N. K. Allam, “Highly Durable Compositionally Variant Bifunctional Tetrametallic Ni–Co–Mn–Fe Phosphide Electrocatalysts Synthesized by a Facile Electrodeposition Method for High-Performance Overall Water Splitting,” Energy Fuels, vol. 36, no. 23, pp. 14371–14381, Dec. 2022, doi: 10.1021/acs.energyfuels.2c03266.

[2] F. Shiokawa et al., “Durable high-entropy non-noble metal anodes for neutral seawater electrolysis,” Chem. Eng. J., vol. 479, p. 147862, Jan. 2024, doi: 10.1016/j.cej.2023.147862.