CdS quantum dots supported by ultrathin porous nanosheets assembled into hollowed-out Co3O4 microspheres: A room-temperature H2S gas sensor with ultra-fast response and recovery

Abstract

With the urgent need to improve societal security, semiconductor-based gas sensors have received substantial attention for their efficiency and accuracy in the detection of harmful gases. However, challenging existed to develop sensors that exhibit both high response and rapid response/recovery rates at room temperature. Herein, we present a simple and energy-efficient room-temperature in situ growth strategy to prepare CdS quantum dots supported by ultrathin porous nanosheets assembled into hollowed-out Co3O4 microspheres (CdS QD/Co3O4 HMSs). XRD, EDX, BET, SEM, TEM and HRTEM analysis confirmed that the interconnected CdS QDs (˜4.5 nm) were well dispersed on the ultrathin porous nanosheet of Co3O4 HMSs. The fabricated CdS QD/Co3O4 HMS sensor exhibited high response (12.7) and ultra-fast response/recovery rates (0.6/1.0 s) to 100 ppm H2S at 25 °C, which is ascribed to high active quantum dots and hollowed-out nanostructure. In addition, the sensor exhibited a low detection limit (1–5 ppm), good reversibility and exceptional long-term stability. This work explores an efficient way to fabricate high-response and ultra-fast response/recovery room-temperature gas sensors by integrating quantum dots with hollowed-out nanostructures.