Theoretical and Experimental Insights into CdO-ZnO Nanocomposites for Gas Sensing
DOI:
https://doi.org/10.32628/IJSRST2512153Keywords:
CdO-ZnO nanocomposite, Ethanol gas sensing, Langmuir adsorption model, Metal oxide sensor, Sol-gel synthesis, Gas response saturationAbstract
Metal oxide nanocomposites have emerged as promising materials for gas sensing applications due to their enhanced surface area, electronic properties, and catalytic activity. This study investigates the ethanol gas sensing characteristics of CdO-ZnO nanocomposites synthesized using the sol-gel method. Structural, morphological, and compositional analyses through XRD, FESEM, EDS, and FTIR confirmed the successful formation of well-integrated CdO-ZnO nanocomposites. The gas sensing response was evaluated for CdO-ZnO nanocomposites out of which CdO-ZnO (70:30) ratio demonstrating the highest gas response (67.23) towards ethanol (50 ppm) at room temperature, optimal response-recovery characteristics, and long-term stability at room temperature. The adsorption mechanism of ethanol gas was analyzed using the Langmuir adsorption model, which showed a strong correlation with experimental data, validating a monolayer adsorption process. The gas response exhibited a sharp increase at lower ethanol concentrations, reaching saturation beyond 50 ppm, confirming the presence of finite active adsorption sites. The smallest particle size (~28 nm) observed for the CdO-ZnO (70:30) composition enhanced the surface-to-volume ratio, leading to improved gas adsorption and electron transfer. Gas sensing study CdO-ZnO (70:30) contribute to the development of high-performance ethanol gas sensors with superior selectivity, high gas response, and long-term operational stability.
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References
S. R. Morrison, The Chemical Physics of Surfaces, 1st ed. New York, NY, USA: Plenum, 1977.
J. R. Stetter and J. Li, “Amperometric gas sensors—A review”, Chemical Reviews, vol. 108, no. 2, pp. 352–366, 2008.
G. Eranna, B. C. Joshi, D. P. Runthala, and R. P. Gupta, “Oxide materials for development of integrated gas sensors—A comprehensive review”, Critical Reviews in Solid State and Materials Sciences, vol. 29, no. 3–4, pp. 111–188, 2004.
J. Watson, “The tin oxide gas sensor and its applications”, Sensors and Actuators, vol. 5, no. 1, pp. 29–42, 1984.
K. Wetchakun, N. Wetchakun, and S. Samerjai, “Semiconducting metal oxides as sensors for environmentally hazardous gases”, Sensors and Actuators B: Chemical, vol. 160, no. 1, pp. 580–591, 2011.
A. Rothschild and Y. Komem, “Electronic structure and gas sensing properties of nanocrystalline metal oxide”, Journal of Applied Physics, vol. 95, no. 11, pp. 6374–6380, 2004.
A. K. Prasad, P. I. Gouma, and P. P. Mukherjee, “Comparison of Langmuir, Freundlich and Temkin adsorption isotherms for Cu–ZnO nanocomposites in gas sensing applications”, Materials Science in Semiconductor Processing, vol. 17, pp. 103–110, 2014.
H. H. Sung, J. H. Yoo, S. H. Lee, J. S. Ha, and J. H. Lee, “Improved gas sensing properties of ZnO nanostructures by surface modification with Pd”, Sensors and Actuators B: Chemical, vol. 179, pp. 189–195, 2013.
M. Haruta, “Size- and support-dependency in the catalysis of gold”, Catalysis Today, vol. 36, no. 1, pp. 153–166, 1997.
D. R. Lide, CRC Handbook of Chemistry and Physics, 88th ed. Boca Raton, FL, USA: CRC Press, 2007.
M. P. Seah and W. A. Dench, “Quantitative electron spectroscopy of surfaces: A standard data base for electron inelastic mean free paths in solids”, Surface and Interface Analysis, vol. 1, no. 1, pp. 2–11, 1979.
J. H. Park, M. S. Hwang, H. S. Kim, and S. C. Lee, “Highly selective and sensitive ethanol sensor using mesoporous ZnO spheres”, Journal of Nanoscience and Nanotechnology, vol. 15, no. 10, pp. 7592–7598, 2015.
Y. Shimizu and M. Egashira, “Basic aspects and challenges of semiconductor gas sensors”, MRS Bulletin, vol. 24, no. 6, pp. 18–24, 1999.
H. Liu, Q. Chen, and J. Li, “Fabrication of hierarchical ZnO-CdO heterojunction nanostructures for enhanced ethanol sensing performance”, RSC Advances, vol. 7, no. 4, pp. 2432–2441, 2017.
J. H. Kim, H. M. Jeong, H. S. Kim, and J. S. Ha, “Enhancement of ethanol sensing performance of ZnO-CdO nanocomposites via heterojunction formation”, Journal of Materials Science: Materials in Electronics, vol. 29, no. 5, pp. 3892–3899, 2018.
J. Zhang, X. Liu, G. Neri, and N. Pinna, “Nanostructured materials for room-temperature gas sensors”, Advanced Materials, vol. 28, no. 5, pp. 795–831, 2016.
Y. H. Luo, T. Y. Hu, L. P. Zhu, and X. B. Wu, “Influence of particle size on the gas sensing properties of metal oxide nanostructures”, Journal of Nanocomposite Research, vol. 22, no. 5, pp. 145–160, 2020.
H. J. Kim, A. Rothschild, Y. Komem, and I. Riess, “The effect of grain size on gas sensitivity of thin film sensors”, Sensors and Actuators B: Chemical, vol. 130, no. 1, pp. 145–152, 2008.
C. Cantalini, M. Pelino, M. Faccio, M. Passacantando, S. Santucci, and L. Lozzi, “Gas sensitivity of thin film tin oxide sensors to ethanol and methane”, Journal of Applied Physics, vol. 86, no. 1, pp. 263–272, 1999.
J. H. Yu, J. Park, H. S. Kim, and S. C. Lee, “Theoretical modeling of Langmuir adsorption for semiconductor gas sensors”, Journal of Physical Chemistry C, vol. 123, no. 10, pp. 5875–5883, 2019.
H. W. Kim, J. H. Park, M. S. Lee, and S. C. Lee, “Effect of oxygen species on the gas sensing properties of ZnO-CdO nanocomposites”, Applied Surface Science, vol. 476, pp. 849–856, 2019.
A. Umar, S. H. Kim, Y. B. Hahn, and M. S. Al-Assiri, “ZnO nanomaterials for gas sensor applications: A review”, Nano-Micro Letters, vol. 7, no. 2, pp. 97–120, 2015.
J. H. Kim, H. M. Jeong, H. S. Kim, and J. S. Ha, “ZnO-CdO heterojunctions for selective ethanol gas sensing”, Journal of Materials Chemistry C, vol. 7, no. 10, pp. 2800–2811, 2019.
H. Liu, Q. Chen, and J. Li, “Surface chemistry and electron transfer in ethanol gas sensing by metal oxide nanostructures”, ACS Applied Materials & Interfaces, vol. 11, no. 4, pp. 4499–4510, 2019.
K. Wetchakun, P. Wanwan, and P. Liewhiran, “Langmuir adsorption theory and its application in semiconductor gas sensing”, Journal of Chemical Physics, vol. 142, no. 12, pp. 124703, 2015.
P. S. Patil, J. W. Kim, H. S. Kim, and H. S. Lee, “The effect of surface coverage on Langmuir-type adsorption in gas sensors”, Applied Physics Letters, vol. 113, no. 6, pp. 062101, 2018.
R. M. Navarro, F. J. Aparicio, and J. L. G. Fierro, “Langmuir and Freundlich adsorption models applied to metal oxide gas sensing”, Chemical Engineering Journal, vol. 334, pp. 91–100, 2017.
M. J. Rodrigues, L. M. R. Afonso, and R. F. Silva, “Adsorption and reaction kinetics in gas sensing: A Langmuirian approach”, Sensors and Actuators B: Chemical, vol. 271, pp. 71–78, 2018.
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