engleski

SnO2-Cellulose nanofibrils (CNF) composites – influence of the structure on the applicability

Nowadays, there is a great demand worldwide for production of novel tailored materials in order to improve various electronic devices through sustainable processes. The main focus is on the use of biopolymers as templates and also as reagents for the production of metal oxide–carbon composites that could be used in catalysis, sensing, and electrochemical devices. In the literature, studies with TiO2-based nanostructured materials fabricated using nano- and/or micro- cellulose fibres as templates have been reported. Cellulose, a renewable biopolymer most abundant on Earth, was used in this research to control the porosity, morphology, and particle size of the derived composite samples at the nanoscale. in addition, the tin(IV) oxide has a similar bandgap as already well-studied TiO2, while has not yet reached as wide applicability. In this work, in order to broaden the spectrum of tin(IV) oxide nanostructures, we investigated the synthetic routes for the preparation of immobilised SnO2-based samples with enhanced reaction surface availability. Also, the influence of post-reaction treatment of the prepared composite samples was investigated. The focus of this work is on the course of non-hydrolytic sol- gel freeze-drying synthesis in combination with reductive mineralization of cellulose. Post- treatment of the samples was carried out under both, inert and atmospheric conditions, over a wide temperature range. The resulting composite samples were thoroughly characterised using powder X-ray diffraction (PXRD) method, which interestingly revealed the diversity of phases present in the samples at different reaction temperatures and atmospheres. In addition, the surface of the samples was investigated by means of grazing incidence X-ray diffraction (GIXRD) method, to explore the potential phase differences in the samples that could finally influence the sample properties. Furthermore, composites were characterised using Fourier transformed infrared (FTIR) spectroscopy, which overall showed the degree of chemical and structural homogeneity of studied composites. Their thermal stability of the samples was confirmed by thermal analysis (TGA/DSC), while the morphologic and surface geometries were studied by scanning electron microscopy (SEM). The photocatalytic activity was investigated by photocatalytic degradation using a model micropollutant. Finally, the humidity sensing properties of the composites were investigated using the solid-state Impedance Spectroscopy (SS-IS) providing insight into electrical features, based on which comparison of the samples, and the idea of additional applicability was discussed in detail.

cellulose nanofibrils ; tin(IV) oxide ; photocatalytic activity ; X-Ray Diffraction

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