Access Type
Open Access Embargo
Date of Award
January 2025
Degree Type
Dissertation
Degree Name
Ph.D.
Department
Chemistry
First Advisor
Stephanie Brock
Abstract
In this dissertation, Ni2-xMnxP (0.0≤x≤1.5) nanoparticles have been synthesized for the first time using the arrested precipitation technique. This synthesis is based on the formation of a nickel phosphide amorphous phase followed by the incorporation of manganese in the next step. Manganese oxide as a byproduct of this reaction can be separated from Ni2-xMnxP (0.0≤x≤1.5) nanoparticles using a new technique. In this strategy, a mixture of oleic acid/water was added to as-synthesized nanoparticles dispersed in hexane. Manganese oxide nanoparticles can be transferred to the water phase while Ni2-xMnxP nanoparticles remain in hexane. Using this method, Ni2-xMnxP can be synthesized up to x=1.5. Purified Ni2-xMnxP (0.0 ≤ x ≤1.5) nanoparticles have been tested as electrocatalysts for the oxygen evolution reaction (OER) process, and different parameters, including geometric and intrinsic activities, stability, and faradiac efficiency have been evaluated for this system. Compared to the most active compositions in Fe2−xMnxP (x ≤ 0.9) and Co2−xMnxP (x ≤ 1.4), the NiMnP precatalyst resulted in the highest OER activity with a geometric overpotential of 280.0 mV at 10 mA/cm2 relative to 302.5 mV for CoMnP and 350.0 mV for Fe1.1Mn0.9P. Magnetic properties of CoMnP and NiMnP nanoparticles have been investigated using an MPMS3 instrument, and different magnetic parameters of these systems were measured. The behavior of as-synthesized CoMnP nanoparticles is not consistent with the bulk system, but upon heating the nanoparticles to 450 °C they follow the magnetic properties of the bulk system. NiMnP nanoparticles exhibit paramagnetism behavior with a small Weiss constant, consistent with antiferromagnetic exchange at low temperature.
Recommended Citation
Aghabozorgi, Fatemeh, "Synthesis Of Mn-Based Transition Metal Phosphide Nanoparticles And Evaluation Of Their Activity As Pre-Catalysts For Electrocatalytic Water Oxidation And Magnetic Applications" (2025). Wayne State University Dissertations. 4193.
https://digitalcommons.wayne.edu/oa_dissertations/4193