Synthesis of Ag-functionalized a-Fe2O3 nanocomposites for ppb-level triethylamine detection

It has been a challenging and urgent task to synthesize high-performance triethylamine (TEA) gas sensors with ppb-level detection. In this paper, Ag-functionalized alpha-Fe2O3 nanocomposites with internal cavities were synthesized by successfully decorating Ag+ on Fe3+ covered carbonaceous microsphere (CMS) templates followed by a calcination step. The sample Fe-Ag-II had an extremely high response (R-a/R-g = 822), a fast response (2 s), excellent selectivity, and long-term stability for 100 ppm TEA, and a high response to ppb-level TEA gas (R-a/R-g = 9.32-50 ppb) at 200 ?. The effect of relative humidity on TEA gas sensing sensors was investigated, which has rarely been reported before. Gas sensing tests revealed that CMS templates and the noble metal Ag could both improve sensing response while lowering the operating temperature. The mechanism of the enhanced gas sensing properties is discussed in detail. This work provides new strategies for the improvement of alpha-Fe2O3 microstructure and the development of more practical TEA sensors. (C) 2022 Elsevier B.V. All rights reserved.