MOF-derived Au-NiO/In2O3 for selective and fast detection of toluene at ppb-level in high humid environments

Development of highly sensitive toluene gas sensor is desirable but challenging for both indoor air quality monitoring and medical diagnosis. Herein, we proposed to design Au nanoparticles (NPs) decorated MOFderived NiO/In2O3 hollow microspheres as efficient sensing materials for toluene detection. Benefiting from the structural merits and synergetic effects, the Au0.6Ni4In-based toluene sensor exhibited a high response, fast response and recovery speed, good linearity, low detection limitation (~5.1 ppb) with excellent selectivity and good stability in both relatively dry (11% RH) and ultra humid (95% RH) atmospheres. The improved toluene detection performance might be attributed to the synergistic effects of several points including the formation of p-n junction between NiO and In2O3, the sensitization effect of Au NPs, high affinity of NiO to water vapor as well as the loose structure. The obtained sensing performances unambiguously indicated that the Au0.6Ni4In-based sensor can quantitatively detect toluene at ppb-level in a complex environment.