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

• The pure and Pd-doped SnO2 nanoparticles are found to have tetragonal rutile structure.
• The FTIR study confirmed the formation of Sn–O phase.
• EDX analysis confirms the presence of palladium.
• The 0.20% Pd-doped sample shows the maximum response at different operating temperature within the measurement limit.

In this article pure and Pd-doped SnO2 (Pd:SnO2) nanoparticles with various mol% Pd have been synthesized by hydrothermal technique. To characterize the morphology, crystallinity, and structure of the SnO2 and Pd:SnO2 X-ray diffraction (XRD) and scanning electron microscope (SEM) studies were used. XRD analysis reveal that all nanoparticles of different doping concentration are highly polycrystalline in nature. Pd-doped SnO2 crystals existed mainly as tetragonal rutile structure. The particle size of the nanoparticles was calculated by using the Scherrer formula and was found in the range of 8–27 nm. The SEM images of the studied nanoparticles confirms the existence of very small, homogeneously distributed, spherical and extremely crystalline nanoparticles. EDX analysis confirms the presence of palladium. The Fourier transform infrared spectroscopy (FTIR) study confirmed the formation of Sn–O phase and hydrous nature of the pure and Pd-doped SnO2 nanoparticles. The gas sensing response of SnO2 and Pd:SnO2 nanoparticles was studied towards different reducing gases at different operating temperatures. Among all samples under study, 0.20% Pd-doped SnO2 exhibits best response towards different gases. 0.20% Pd-doped SnO2 shows maximum response 88% to ethanol, 80% to CO and 78% to H2 at concentration of 100 ppm respectively at different operating temperature within the measurement limit.

The X-ray diffraction patterns (XRD) of pure and Pd-doped SnO2 samples for different concentrations were investigated with X-ray diffractometer. The observed pattern has a number of sharp peaks at (110), (101), (200), (211), (002), (310) and (112) at different angles (2θ). All the diffraction peaks were perfectly indexed to rutile structure of pure SnO2 with lattice parameters (a = b = 4.738 Å, c = 3.187 Å) which is consistent with the standard data file (JCPDS card, No.41-1445) for SnO2. The average crystallite size along (110) & (101) peaks decreases from 27 to 8 nm with increase in doping of Pd from x = 0.05–0.20 %.Figure optionsDownload as PowerPoint slide