Nonaqueous synthesis of Ag-functionalized In2O3/ZnO nanocomposites for highly sensitive formaldehyde sensor

Abstract In this work, Ag-functionalized In 2 O 3 /ZnO (IZO) nanocomposites with various contents were successfully fabricated by a nonaqueous route. The ZnO and In 2 O 3 showed separated phases and different sizes deriving from the faster growth of ZnO than In 2 O 3 using benzyl alcohol as the oxygen supplying agent. To demonstrate the usage of such Ag-functionalized IZO, the gas sensors have been fabricated and investigated for formaldehyde (HCHO) detection. The results reveal that the as-synthesized 3 wt% Ag-functionalized IZO samples exhibit high response of about 842.9 towards 2000 ppm HCHO at operating temperature of 300 °C. All sensors show rapid response and recovery. The highly sensing properties are attributed to the synergistic effects arising from the presence of these multiple functional materials, i.e. the special structure of IZO nanocomposites, the formation of the heterojunctions, the influence of Ag nanoparticles, and the mutual doping effect.

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