(544fq) Catalytic Activity of Magnetic Nanoparticles Activated Via RF Induction Heating

The catalysis market is responsible for more than 35% of the world’s GDP and it is involved in the most successful industrial sectors: energy generation, chemicals, and pharmaceuticals. Despite the remarkable advances in catalytic technologies, the industry still faces thermal management issues and accumulation of heat on reactor walls. To overcome thermal transport problems, heat can be generated in situ with the utilization of iron oxide (Fe₃O₄) nanoparticles. In this work, Fe₃O₄ nanoparticles will be used to convert alternating magnetic fields to heat to study the effects of localized energy on the chemical transformation in a reference alcohol condensation reaction.

To demonstrate this chemical transformation, ~20 nm iron oxide nanoparticle spheres, cubes, and truncated octahedrons of tunable sizes are investigated for RF induced catalysis. The size and shape of these particles is controlled by varying surfactant to precursor ratio in thermal decomposition reactions. These facets allow for the tuning of surface activity and heat generation, key parameters for selectivity and activity engineering. The heat generated is dependent on the spin configuration on the surface, with minimum heating rates at least 34% higher than commercially available particles. Surface functionalization with hydroxyl groups is performed to increase the interaction of Fe₃O₄ with alcohols in dehydrogenation reactions. Additionally, this localized heat generation can be used to control surface functionalization for dispersion in aqueous solutions and conversion of alcohols. For spherical particles, the GC-MS data shows production of aldehydes and esters via thermal routes while RF induced reactions result in longer alkenes such as decene. Additionally, the intensity of the magnetic field applied changes the reaction products. These results indicate changes in the reaction mechanism associated with RF activation. Furthermore, to investigate the role of the surface of iron oxide without any surfactants on the mechanism of the reaction, spherical nanoparticles are also synthesized via co-precipitation routes. The catalyst is characterized before and after functionalization and reaction steps to probe the crystal structure, oxidation states of iron and morphology of the particles, using XRD, XPS and HRTEM respectively. The reaction products are characterized via GC-MS to elucidate the reaction mechanism.