Apr 24, 2013
Magnetic fields drive ZnO nanostructures
Italian researchers based at the Institute of Materials for Electronics and Magnetism IMEM-CNR in Parma have created a composite nanostructure made of zinc oxide (ZnO) tetrapod-shaped crystals and nanometric magnetite (Fe3O4) nanoparticles with super-paramagnetic properties. In the sample, the attractive features of the ZnO component – strong UV emission and a free active surface – remain unchanged. Therefore, the nanocomposite can be potentially employed in different technological fields, such as photocatalytic systems, gas-sensing devices, water splitting and biomedical applications, for example drug delivery and photodynamic therapy.
In the work, the use of the composite material for filter-free photocatalysis has been evaluated as a case study. By measuring the degradation rate of two organic dyes (see video), the team found that the combined material outperformed bare ZnO tetrapods in tests. In addition, the superparamagnetic properties of the composite permit easy, on-demand recovery from the treated water following the application of a magnetic field, which avoids the need for further downstream filtering.
As a further perspective, the combination of magnetic and piezoelectric properties in one composite material paves the way for the realization of new-concept systems with piezo-magnetic functionalities.
Full details can be found in the journal Nanotechnology.
About the author
This research was carried out at the Institute of Materials for Electronics and Magnetism (IMEM-CNR) in Parma (Italy). Marco Villani is a postdoc and Tiziano Rimoldi is a PhD student, working on nanocrystal growth with Davide Calestani (researcher) and Andrea Zappettini (group head) in the “SIGNAL” group. Other colleagues from the same Institute working in complementary fields have been involved in this study: Laura Lazzarini is a researcher in the microscopy group, and Valentina Chiesi (PhD student), Francesca Casoli (researcher) and Franca Albertini (group head) are all members of the magnetism group.