Synthesis of Discrete Transition Metal (Ni, Co, Fe, Mn) Phosphide Nanoparticles: Compositional Effect on Catalytic And Magnetic Properties

摘要

This dissertation research is focused on the synthesis, characterization of binary and ternary transition metal (Ni, Co, Fe, Mn) phosphide nanomaterials and their catalytic and magnetic properties.;A phase-control strategy enabling the arrested-precipitation synthesis of nanoparticles of Ni5P4 and NiP2 is presented. The composition and purity of the product can be tuned by changing key synthetic levers, including the metal precursor, the oleylamine (OAm) and Trioctylphosphine (TOP) concentrations, temperature, time and the presence or absence of a moderate temperature soak step to facilitate formation of Ni and/or Ni-P amorphous nanoparticle intermediates.;New CoxFe2-xP nanoparticles (0 ≤ x ≤ 2), Co2-xMnxP nanoparticles (0 ≤ x ≤ 1.4), and Fe 2-xMnxP nanorods (0 ≤ x ≤ 0.9) are synthesized with control of size, morphology, and composition. The CoxFe2-x P nanoparticles exhibit composition dependent magnetic properties, while M2-xMnxP (M = Co, Fe) nanomaterials are capable of catalyzing water oxidation at low overpotentials with high Faradaic efficiency. A new protocol is established to combine metal chalcogenide semiconductor aerogels with Ni2P nanoparticles. The resulting hybrid aerogels are photocatalytically active for the hydrogen evolution reaction (HER).