Baek, Jong Won Han, Seunghee Lee, Sang Eun Ahn, Jaewan Park, Chungseong Nam, Jong Seok Kim, Yoon Hwa Shin, Euichul Kim, Minhyun Jang, Ji-Soo Kim, Jihan Park, Hee Jung Kim, Il-Doo 2024-08-01T06:00:48Z 2024-08-01T06:00:48Z 2024-08-01 2024-07 1936-0851 https://pubs.kist.re.kr/handle/201004/150345 Chemiresistive gas sensors based on semiconducting metal oxides typically rely on noble metal catalysts to enhance their sensitivity and selectivity. However, noble metal catalysts have several drawbacks for practical utilization, including their high cost, their propensity for spontaneous agglomeration, and poisoning effects with certain types of gases. As such, in the interest of commercializing the chemiresistive gas sensor technology, we propose an alternative design for a noble-metal-free sensing material through the case study of Co-doped ceria (Co-CeO2) catalysts embedded in a SnO2 matrix. In this investigation, we utilized electrospinning and subsequent calcination to prepare Co-CeO2 catalyst nanoparticles integrated with SnO2 nanofibers (NFs) with uniform particle distribution and particle size regulation down to the sub-2 nm regime. The resulting Co-CeO2@SnO2 NFs exhibited superior gas sensing characteristics toward isoprene (C5H8) gas, a significant biomarker for monitoring the onset of various diseases through breath diagnostics. In particular, we identified that the Co-CeO2 catalysts, owing to the transition metal doping, facilitated the spillover of chemisorbed oxygen species to the SnO2 sensing body. This resulting in the sensor having a 27.4-fold higher response toward 5 ppm of C5H8 (compared to pristine SnO2), exceptionally high selectivity, and a low detection limit of 100 ppb. The sensor also exhibited high stability for prolonged response-recovery cycles, attesting to the strong anchoring of Co-CeO2 catalysts in the SnO2 matrix. Based on our findings, the transition metal-doped metal oxide catalysts, such as Co-CeO2, demonstrate strong potential to completely replace noble metal catalysts, thereby advancing the development of the commercially viable chemiresistive gas sensors free from noble metals, capable of detecting target gases at sub-ppm levels. English American Chemical Society Cobalt-Doped Ceria Sensitizer Effects on Metal Oxide Nanofibers: Heightened Surface Reactivity for High-Performing Chemiresistive Sensors Article 10.1021/acsnano.4c03168 1 ACS Nano, v.18, no.30, pp.19568 - 19580 ACS Nano 18 30 19568 19580 Y scie scopus 001270089700001 2-s2.0-85198723235 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science Article CATALYTIC-ACTIVITY BREATH ISOPRENE CEO2 SNO2 OXYGEN OXIDATION COMBUSTION SCAFFOLD STORAGE IN2O3 cerium oxide doping metal oxide electrospinning gas sensor