Microwave-assisted hydrothermal synthesis of Zn₂SnO₄ nanostructures for photocatalytic dye degradation

Zinc-tin oxide (ZTO) material system possesses a wide range of attractive properties for a new generation of multifunctional nanodevices. It can crystallize in Zn₂SnO₄ and ZnSnO₃ phases, with different types of nanostructures possible for each phase. Each has unique properties suitable for applications in catalysis, sensors, transistors, memories, or energy harvesting devices [1,2]. In previous works an in-depth study on the influence of the chemico-physical parameters of a seed-layer free hydrothermal synthesis in a conventional oven (24 h at 200 °C) allowed to control the achievement of different types of ZTO nanostructures [3,4]. An alternative route to circumvent the inconveniently long synthesis durations in a conventional oven is the microwave heating assisted synthesis, which allows to achieve accelerated chemical reactions [5]. As such, in this work it is shown that Zn₂SnO₄ nanoparticles, octahedrons and nanoplates are obtained by microwave-assisted synthesis with reduced processing times of up to 22 h, while still yielding reproducible and homogeneous results. The photocatalytic activity of the Zn₂SnO₄ nanostructures produced using the microwave system are evaluated for rhodamine B degradation under UV light, being observed a better performance for Zn₂SnO₄ nanoparticles with >90 % of degradation in 2.5 hours.

1. A. Rovisco et al., Hydrothermal Synthesis of Zinc-Tin Oxide Nanostructures for Photocatalysis, Energy Harvesting and Electronics, in Novel Materials, IntechOpen, 2020. Accepted
2. A. Rovisco et al., ACS Appl. Mater. Interfaces 2020, 12, 18421–18430.
3. A. Rovisco et al., ACS Appl. Nano Mater. 2018, 1, 3986–3997.
4. A. Rovisco et al., Nanomaterials 2019, 9, 1002.
5. D. Nunes et al., Catalysis Today 2016, 278, 262-270.