Synthesis of Photoactive Magnetic Nanoparticles with Atomic Layer Deposition

Published

March 8, 2010

Author(s)

Yun Zhou, David M. King, Jianhua Li, Kathryn S. Barrett, Ronald B. Goldfarb, Alan W. Weimer

Abstract

Iron-based magnetic nanoparticles have been produced by decomposition of iron oxalate powder. The micron-sized iron oxalate powder was first ground using a cryogenic milling process. A titanium dioxide (TiO₂) thin film was then deposited on the synthesized iron nanoparticles using an in-situ atomic layer deposition (ALD) process at 100 °C with TiCl₄ and H₂O₂ as precursors. However, due to the high surface area, the iron nanoparticles were unstable and spontaneously oxidized when exposed to H₂O₂ during the TiO₂ ALD process, thus reducing the magnetic moment of the core particles. As an improvement in the process, prior to the TiO₂ deposition, an aluminum nitride (AlN) film was deposited in-situ to coat and passivate the iron core particles. The AlN ALD was performed at 250 °C using trimethylaluminium (TMA) and ammonia (NH₃) as precursors. This passivation provided for a significant decrease in the iron oxidation as determined by X-ray diffraction and magnetization measurements. Photoactivity of the TiO₂ film was demonstrated by decomposing methylene blue solution under ultraviolet irradiation.

Citation

Industrial and Engineering Chemistry Research

Volume

49

Issue

15

Pub Type

Journals

Download Paper

DOI Link

Keywords

Iron nanoparticles, atomic layer deposition, titanium dioxide, aluminum nitride, passivation, photocatalyst

Citation

Zhou, Y. , King, D. , Li, J. , Barrett, K. , Goldfarb, R. and Weimer, A. (2010), Synthesis of Photoactive Magnetic Nanoparticles with Atomic Layer Deposition, Industrial and Engineering Chemistry Research, [online], https://doi.org/10.1021/ie901712q (Accessed October 27, 2025)