Cost and performance analysis of transition metal phosphides for PEM electrolyzers

Abstract

This study evaluates the economic and technical viability of using transition metal phosphides (TMPs), specifically FeP/CB and CoP/CB, as platinum-free catalysts in proton exchange membrane (PEM) electrolyzers. A 100 kW system was modeled to compare efficiency, durability, capital cost, and the levelized cost of hydrogen (LCOH) with traditional Pt-based benchmarks. The analysis shows that while TMP-based systems may need a slightly larger surface area because of lower efficiencies, both FeP/CB and CoP/CB achieve LCOH values similar to those of Pt-based systems. For an electricity price of $0.05 kWh⁻¹, the calculated LCOH values range from approximately $3.6–$4.0 kg⁻¹ H₂, corresponding to system efficiencies of 67.5 % (FeP/CB) and 65.1 % (CoP/CB). Of the two, FeP/CB shows better performance with higher efficiency and a longer projected lifetime. CoP/CB also shows comparably competitive performance. These findings indicate that TMP catalysts can help reduce reliance on rare and expensive platinum group metals while ensuring cost-effective hydrogen production, thus supporting the growth of green hydrogen technologies.

Keywords

• Transition metal phosphides
• PEM electrolyzers
• Techno-economic analysis
• Pt-free catalysts
• Levelized cost of hydrogen

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