High-throughput discovery of hydrogen evolution electrocatalysts in the complex solid solution system Co–Cr–Fe–Mo–Ni

Abstract

Discovery of new electrocatalysts requires the combination of high-throughput synthesis and high-throughput screening techniques to explore the vast compositional range of compositionally complex solid solutions (CCSS). This work explores more than 1000 different compositions of the quinary CCSS system Co–Cr–Fe–Mo–Ni as electrocatalysts for the hydrogen evolution reaction (HER). Thin-film material libraries prepared by magnetron co-sputtering are characterized, and their electrocatalytic activity towards hydrogen formation via water electrolysis in alkaline electrolyte is evaluated using a scanning droplet cell (SDC). Using this high-throughput approach, we identified 349 compositions in the Co–Cr–Fe–Mo–Ni space with similar or higher electrocatalytic activity than Co₃₅Cr₁₅Fe₂₀Mo₁₀Ni₂₀, which was recently reported as a HER catalyst. The highest activity from the explored Co–Cr–Fe–Mo–Ni CCSS system was found for Co₅₆Cr₈Fe₁₉Mo₇Ni₁₀.