Abstract

This work reports the successful hydrothermal synthesis of pristine β-MnO2 and its nanocomposite with TiO2 via solid state method. The structural analysis of the synthesised samples via X-ray diffraction spectroscopy (XRD) revealed the tetragonal phase of β-MnO2 and β-MnO2-TiO2 and their high crystalline nature. The crystallinity of the pristine and composite is 71.32% and 89.17% respectively, which shows the increment in the crystallinity with the composite. The percentage of tetragonal phase of β-MnO2 in the composite is 68.75% and the percentage of tetragonal phase of TiO2 is 31.24%. The average crystallite size showed a decrease from 26.57nm in pristine to 22.43nm as reported in composite. The lattice strain is obtained via the W-H analysis of the samples. The lattice strain is  and 7.04  in pristine and composite shows the strain decreases in the composite. The morphology reports short nano-threads of β-MnO2 arranged in scattered coral type structure. The composite shows dispersed granules of TiO2 with small β-MnO2 threads accompanied with high surface area and porosity. The UV-Visible analysis revealed the absorption peak and the optical energy band gap analysis revealed the band gap of β-MnO2 and β-MnO2-TiO2. The band gap reduced to 3.6eV in composite from 4.9eV in pristine. The functional band analysis using FT-IR showed the existence of only Mn-O and both Mn-O and Ti-O vibration band in spectra of pristine and composite respectively. The increase in crystallinity, porosity and decrease in the crystallite size, strain, band gap in the nanocomposite can enhance the gas sensing application of the fabricated thin films.

Keywords

Manganese oxide, Nanocomposite, Gas Sensing Application, Thin Films, FT-IR, XRD,

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References

  1. X. Zhang, P. Yu, H. Zhang, D. Zhang, X. Sun, Y. Ma, Rapid hydrothermal synthesis of hierarchical nanostructures assembled from ultrathin birnessite-type MnO2 nanosheets for supercapacitor applications, Electrochimica Acta, 89, (2013) 523-529. https://doi.org/10.1016/j.electacta.2012.11.089
  2. W. Zhang, C. Zeng, M. Kong, Y. Pan, Z. Yang, Water-evaporation-induced self-assembly of a-MnO2 hierarchical hollow nanospheres and their applications in ammonia gas sensing, Sensors Actuators, B Chemical, 162(1), (2012) 292–299. https://doi.org/10.1016/j.snb.2011.12.080
  3. M.R. Sovizi, S. Mirzakhani, Highly sensitive detection of ammonia gas by 3D flower-like ɤ-MnO2 nanostructure chemiresistor, Journal of the Taiwan Institute of Chemical Engineers, 111, (2020) 293–301. https://doi.org/10.1016/j.jtice.2020.04.017
  4. B.O. Taranu, S.D. Novaconi, M. Ivanovici, J.N. Gonçalves, F.S. Rus, α-MnO2 Nanowire Structure Obtained at Low Temperature with Aspects in Environmental Remediation and Sustainable Energy Applications, Applied Sciences, 12, (2022) 6821. https://doi.org/10.3390/app12136821
  5. Z. Zhao, G. Li, Y. Sun, N. Li, Z. Zhang, J. Cheng, C. Ma, Z. Hao, The positive effect of water on acetaldehyde oxidation depended on the reaction temperature and MnO2 structure, Applied Catalysis B: Environmental, 303, (2022) 120886. https://doi.org/10.1016/j.apcatb.2021.120886
  6. B. Li, X. Wang, M. Yan, L. Li, Preparation and characterization of nano-TiO2 powder, Materials Chemistry and Physics, 78(1), (2003) 184-188. https://doi.org/10.1016/S0254-0584(02)00226-2
  7. S. Devaraj, N. Munichandraiah, Effect of crystallographic structure of MnO2 on its electrochemical capacitance properties, The Journal of Physical Chemistry C, 112, (2008) 4406-4417. https://doi.org/10.1021/jp7108785
  8. A. Verma, P. Chaudhary, A. Singh, R.K. Tripathi, B.C. Yadav, ZnS nanosheets in a polyaniline matrix as metallopolymer nanohybrids for flexible and biofriendly photodetectors, ACS Applied Nano Materials, 5, (2022) 4860-4874. https://doi.org/10.1021/acsanm.1c04437