Structural, morphological and gas sensing study of zinc doped tin oxide nanoparticles synthesized via hydrothermal technique

• The pure and Zn-doped SnO2 nanoparticles are found to have crystallite sizes in range of 9–21 nm.
• The formation of Sn–O phase and hydrous nature of Zn-doped SnO2 nanoparticles was confirmed by FTIR study.
• EDX analysis confirms the presence of zinc, tin and oxygen.
• The 0.20% Zn-doped sample shows the maximum response at gas concentration of 100 ppm at different operating temperature within the measurement limit.

The pure and Zn-doped SnO2 nanoparticles were prepared successfully by hydrothermal route on large scale having different doping concentration of zinc from 0 to 0.20%. The calcined nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) for structural and morphological studies. XRD analyses reveal that the nanoparticles of these doping concentrations are polycrystalline in nature and existed as tetragonal rutile structure, SEM study of images confirms the existence of very small, homogeneously distributed, and spherical nanoparticles. The particles size of the nanoparticles was calculated by Scherrer formula and was found in the range of 9–21 nm. The presence of dopant (i.e. zinc) and formation of Sn–O phase and hydrous nature of Zn-doped SnO2 nanoparticles are confirmed by EDX and FTIR study. The gas sensing properties of pure and Zn-doped SnO2 nanoparticles were investigated for various concentrations of methanol, ethanol and acetone at different operating temperatures and it has been found that with doping concentration of zinc (x = 0.20%) shows the maximum response 78% to methanol, 65% to ethanol and 62% to acetone respectively at different operating temperature within the measurement limit for a concentration of 100 ppm of each gases.

XRD patterns of calcined (400 °C) pure and Zn-doped SnO2 nanoparticles have shown sharp peaks at (110), (101), (200), (211), (002), (310) and (112) at different diffracting angles (2θ). The XRD patterns of different samples have shown very clear and single diffraction peaks, which indicate a good homogeneity and crystallinity of the samples. All the diffraction peaks indexed to rutile tetragonal structure of SnO2 with lattice parameters a = b = 4.737 Å and c = 3.185 Å which is in consistent with the standard data file (JCPDS file No. 72-1147) for SnO2. It has been observed that diffraction peak positions of doped samples shifts towards lower values of 2θ as compared to the peak position observed in pure sample. XRD patterns have also shown that the value of full-width half-maximum (FWHM) increased with increase of Zn concentration, which is an indication of deterioration of crystallinity and the decrease of crystallite size in xZn(1-x)SnO2 samples. By comparing width of diffraction peaks of Zn doped SnO2 with pure SnO2 it has found that sizes of pure SnO2 crystals are larger than that of Zn-doped SnO2 crystals. The average crystallite size is estimated using by Scherrer formula and was found in the range of 9–21 nm.Figure optionsDownload as PowerPoint slide