Converting silicon nanoparticles into nickel iron silicide nanocrystals within molten salts for water oxidation electrocatalysis

Yang Song (1) , Sandra Casale (2) , Antoine Miche (2) , David Montero (3) , Christel Laberty-Robert (4) , David Portehault (1)

1 LCMCP-NANO - Novel Advanced Nano-Objects
2 LRS - Laboratoire de Réactivité de Surface
3 IMPC - Institut des matériaux de Paris-Centre
4 LCMCP-RMES - Reactive Materials for Electrochemical Systems

We synthesize metal silicide electrocatalysts for water oxidation, by using the high reactivity of silicon nanoparticles and the unique stability and low vapor pressure of molten salt solvents. We can then perform liquid-phase synthesis under vacuum at 300-400 C. This strategy yields FeSi, Ni 2 Si, and Fe-doped Ni 2 Si nanocrystals, which exhibit high electrocatalytic activity for the oxygen evolution reaction with an overpotential of 337 mV at 10 mA cm À2 in 0.1 M KOH for Ni 2 Si doped with optimal iron content. We report high stability over 85 hours. Post mortem studies reveal a core-shell-shell nanostructure, where the core remains crystalline Ni 2Àx Fe x Si enabling charge percolation.

Domaines: Chimie; Matériaux; Chimie inorganique; Catalyse

Yang Song, Sandra Casale, Antoine Miche, David Montero, Christel Laberty-Robert, et al.. Converting silicon nanoparticles into nickel iron silicide nanocrystals within molten salts for water oxidation electrocatalysis. Journal of Materials Chemistry A, 2022, 10 (3), pp.1350-1358. ⟨10.1039/D1TA08097K⟩. ⟨hal-03537470⟩