“Spray Pyrolysis: A Green Approach to Thin-Film-Based Pollution Detection”

Spray pyrolysis has emerged as a promising green and versatile approach for the fabrication of functional thin films for pollution detection and environmental monitoring. The reviewed studies demonstrate that its simple operation, low cost, atmospheric-pressure processing, scalability, and compositional flexibility provide significant advantages over several conventional thin-film deposition techniques. The ability to control precursor concentration, substrate temperature, spray rate, deposition time, and nozzle-to-substrate distance enables effective tailoring of film structure, morphology, and functional properties. Nanostructured metal-oxide films prepared by this technique have shown considerable potential for detecting toxic gases, volatile organic compounds, and other environmental pollutants. Doping, nanostructure engineering, and heterojunction formation further provide opportunities to enhance sensitivity, selectivity, response, recovery, and stability. Despite these advantages, challenges associated with humidity interference, long-term stability, reproducibility, and low-concentration detection remain. Future efforts should emphasize green precursors, energy-efficient deposition, flexible substrates, low-temperature operation, and integration with portable sensing platforms. Such developments can contribute significantly to sustainable pollution monitoring and environmental protection.

[1]  Sriram, S. R., Parne, S., Pothukanuri, N., & Edla, D. R. (2022). Prospects of spray pyrolysis technique for gas sensor applications—A comprehensive review. Journal of Analytical and Applied Pyrolysis, 164, 105527. https://doi.org/10.1016/j.jaap.2022.105527 [2]  Sivaperuman, K., Thomas, A., Thangavel, R., & Thirumalaisamy, L. (2024). Binary and ternary metal oxide semiconductor thin films for effective gas sensing applications: A comprehensive review and future prospects. Progress in Materials Science, 142, 101222. [3]  Patil, P. S. (1999). Versatility of chemical spray pyrolysis technique. Materials Chemistry and Physics, 59(3), 185–198. https://doi.org/10.1016/S0254-0584(99)00049-8 [4]  Perednis, D., & Gauckler, L. J. (2005). Thin film deposition using spray pyrolysis. Journal of Electroceramics, 14, 103–111. https://doi.org/10.1007/s10832-005-0870-x [5]   Gurav, K. V., & Mane, R. S. (2014). Perspectives of spray pyrolysis for facile synthesis of catalysts and thin films: An introduction and summary of recent directions. Catalysis Today, 238, 87–94. https://doi.org/10.1016/j.cattod.2014.03.056 [6]   Mwakikunga, B. W. (2014). Progress in ultrasonic spray pyrolysis for condensed matter sciences developed from Michael Faraday. Critical Reviews in Solid State and Materials Sciences, 39(1), 46–80. https://doi.org/10.1080/10408436.2012.687359 [7]  Kodas, T. T., & Hampden-Smith, M. J. (1999). Aerosol processing of materials. Wiley-VCH. [8]  Blandenet, G., Court, M., & Lagarde, Y. (1981). Thin layers deposited by the pyrosol process. Thin Solid Films, 77, 81–90. https://doi.org/10.1016/0040-6090(81)90362-X [9]  Patil, S. B., Patil, G. E., & Dalal, P. V. (2024). Enhanced gas sensing performance of ZnO and Pt-doped ZnO nanostructured films by chemical spray pyrolysis. Surfaces and Interfaces, 54, 105173. https://doi.org/10.1016/j.surfin.2024.105173 [10] Aher, Y. B., More, M. A., Jain, G. H., Shinde, S. D., Sonawane, L. D., Patil, D. Y., Mandawade, A. S., Ahemad, H. I., Kim, J. M., Bulakhe, R. N., & Patil, G. E. (2026). Highly selective and fast-response NH₃ gas sensor based on Ag-doped WO₃ thin films prepared by spray pyrolysis. Talanta, 302, 129479. https://doi.org/10.1016/j.talanta.2026.129479