A comparative structural and photocatalytic study on SnO2 nanoparticles fabricated in batch reactor and microreactor

Abstract

Controlling of scalability, agglomeration and monodispersity of nanoparticles are fundamental to be exploited in diverse application-based fields such as catalysis, sensing, drug delivery, bio-imaging etc. Currently fabrication of scalable, non-agglomerated and monodispersed nanoparticles by using continuous flow microreactor technology pay severe consideration as it offers a variety of advantages such as competent heat transfer and better intermixing of the reactants compare to the conventional batch reactor technology. In this contribution, we advance the prior art by introducing a straightforward, scalable, cost-effective and environmentally benign continuous flow microreactor synthetic approach for the fabrication of pristine SnO2 nanoparticles at a reasonably low reaction temperature and short reaction period. A PTFE (polytetrafluoroethylene)-based helical tubular microreactor is being exploited that comprises compact structure and offers enhanced heat and mass transport as well as better intermixing among the reactants. To discriminate this technique with the conventional batch reactor method herein SnO2 nanoparticles have been synthesized by using both techniques by maintain the identical reaction temperature and reaction time in both cases. Inherent crystal phases, lattice strain, lattice parameters and oxygen vacancies of the as-synthesized SnO2 nanoparticles have been investigated by using XRD/Rietveld analysis. High resolution (HR) -Transmission electron microscopy (TEM) is carried out to investigate the size, shape, crystallinity and agglomeration behaviour of the SnO2 nanoparticles fabricated by each method. SnO2 nanoparticles fabricated by microreactor technology demonstrate excellent activity in the degradation of methylene blue (MB) dye and good stability in response to irradiation. Results demonstrate that altering the synthetic technique amends both surface properties (extent of oxygen vacancies and defects at the surface) and optical band gaps and that these alterations are eventually reflected in the photocatalytic properties of the SnO2 nanoparticles.