posted on 2023-11-08, 14:20authored byMenuka Adhikari, Shubham Sharma, Elena Echeverria, David N. McIlroy, Yolanda Vasquez
Iron phosphide (FeP) nanoparticles have excellent properties
such
as fast charge transfer kinetics, high electrical conductivity, and
high stability, making them a promising catalyst for hydrogen evolution
reaction (HER). A challenge to the wide use of iron phosphide nanomaterials
for this application is the available synthesis protocols that limit
control over the resulting crystalline phase of the product. In this
study, we report a method for synthesizing FeP through a solution-based
process. Here, we use iron oxyhydroxide (β-FeOOH) as a cost-effective,
environmentally friendly, and air-stable source of iron, along with
tri-n-octylphosphine (TOP) as the phosphorus source
and solvent. FeP is formed in a nanobundle morphology in the solution
phase reaction at a temperature of 320 °C. The materials were
characterized by pXRD and transmission electron microscopy (TEM).
The optimization parameters evaluated to produce the phosphorus-rich
FeP phase included the reaction rate, time, amount of TOP, and reaction
temperature. Mixtures of Fe2P and FeP phases were obtained
at shorter reaction times and slow heating rates (4.5 °C /min),
while longer reaction times and faster heating rates (18.8 °C/min)
favored the formation of phosphorus-rich FeP. Overall, the reaction
lever that consistently yielded FeP as the predominant crystalline
phase was a fast heat rate.