Highly sensitive and selective ethylene gas sensors based on CeO<inf>x</inf>-SnO<inf>2</inf> nanocomposites prepared by a Co-precipitation method

Abstract

© 2020 Elsevier B.V. CeOx-SnO2 nanocomposites (NCs) with different Ce:Sn compositions of 0:100, 20:80, 25:75, 33:67, 50:50 and 100:0 were synthesized via a two-reactant co-precipitation method. The phase, morphology, particles size, elemental composition and chemical state of as-prepared CeOx-SnO2 nanoparticles (NPs) were characterized by X-ray diffraction, nitrogen adsorption, electron microscopy and X-ray spectroscopy. The results revealed that the highly crystalline solid solution phases structure of CeOx-SnO2 were formed exhibiting approximately round morphologies with average particles sizes of ~5–20 nm. The sensor properties towards ethylene gas were characterized in terms of response, response times, stability and selectivity. The gas-sensing data showed that the addition of CeOx to SnO2 provided significant enhancement of ethylene response and the CeOx-SnO2 NPs (Ce:Sn = 33:67) offered the highest response of 5.18 with a short response time of 12 s to 10 ppm ethylene at 350 °C. Additionally, the sensor exhibited a low minimum detectable ethylene concentration of 0.3 ppm, high ethylene selectivity and good stability. Therefore, the sensor based on coprecipitated CeOx-SnO2 NPs could ce a promising candidate for detection of ethylene in fruit-ripeness monitoring applications.