A comparative investigation on humidity sensing and photocatalytic applications of Sb doped SnO2 by microwave combustion route

This work highlights the high sensitivity humidity sensor and photocatalytic activity of pure and Sb doped SnO2 nanoparticles by microwave combustion route. The role of Sb dopant on structural, morphological and optical properties were systematically investigated by powder X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Raman spectra, UV–Vis absorption spectra and Photoluminescence spectra analysis. PXRD and Raman results reveal that SnO2 is nanocrystalline with tetragonal structure. The structure of SnO2 does not change with Sb doping but the shape of the nanoparticles changes from spherical to needle like morphology by Sb doped SnO2, which is confirmed through FESEM micrographs. Tuning of band gap and enhanced absorption edge was found to be UV and PL spectra analysis. The Sb doped SnO2 sample showed high performance humidity sensing such as high sensitivity, fast response (40 s) and recovery time (35 s). The photocatalytic activities of the samples were evaluated by photocatalytic degradation of Methylene blue and Crystal violet and the results showed that Sb doped SnO2 could enhance photocatalytic activity compared to the undoped SnO2 nanoparticles. The most probable photocatalytic mechanism is also proposed in detail.