Comparative Evaluation of Chemically and Green-Synthesized Silica-Modified CeO₂ Nanostructures for Time-Dependent Room-Temperature Ammonia Sensing
Evaluación comparativa de nanoestructuras de CeO₂ modificadas con sílice, sintetizadas química y ecológicamente, para la detección de amoníaco a temperatura ambiente en función del tiempo
Avaliação comparativa de nanoestruturas de CeO₂ modificadas com sílica, sintetizadas quimicamente e por métodos ecológicos, para detecção de amônia em função do tempo e à temperatura ambiente
| 2026 | |
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Nanopartículas de sílice Síntesis verde Óxido de cerio Sensor quimiorresistivo de amoníaco Detección de gases a temperatura ambiente Silica nanoparticles Green synthesis Cerium oxide Chemiresistive ammonia sensor Room-temperature gas sensing Nanopartículas de sílica Síntese verde Óxido de cério Sensor quimiorresistivo de amônia Detecção de gases em temperatura ambiente |
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| Español | |
| Universidad de Montevideo | |
| REDUM | |
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https://revistas.um.edu.uy/index.php/ingenieria/article/view/1976
https://hdl.handle.net/20.500.12806/3447 |
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| Acceso abierto | |
| Atribución 4.0 Internacional |
| Sumario: | Silica nanoparticles were synthesized via two distinct routes – a conventional chemical process and a sustainable green approach using sugarcane bagasse – and incorporated into cerium oxide (CeO₂) nanostructures for comparative evaluation as room-temperature ammonia (NH₃) gas sensors. The chemical route yielded silica by precipitating sodium silicate, whereas the green route extracted bio-silica from agricultural waste (sugarcane bagasse). Both silica types were integrated with CeO₂ through a precipitation/coating method to form silica–modified CeO₂ composite nanoparticles, which were fabricated into chemiresistive sensor devices. Structural characterization by scanning electron microscopy (SEM) revealed an elongated, rod-like CeO₂ morphology distributed in a silica-rich matrix, and energy-dispersive X-ray spectroscopy (EDS) confirmed the presence of Si, Ce, and O, indicating successful composite formation. Gas sensing tests demonstrated that all sensors responded to NH₃ at room temperature, with an initial rapid decrease in resistance upon NH₃ exposure. The gas response (defined as change in resistance ratio) reached over 600% within seconds of exposure for fresh sensors and progressively increased with continued exposure up to 10 min. After 15 min of continuous NH₃, however, the sensor response became negative (~–11%), suggesting surface saturation or irreversible adsorption of NH₃ on the active sites. These results suggest that sugarcane bagasse-derived silica can produce NH₃ response trends broadly comparable to chemically synthesized silica under the present experimental conditions. However, a full statistical comparison using multiple devices is still required to confirm equivalent performance. The incorporation of green-sourced silica thus provides an environmentally friendly pathway to high-performance, room-temperature gas sensors, though calibration and long-term stability tests are needed for further development. |
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