Low temperature acetylene gas sensor based on Ag nanoparticles-loaded ZnO-reduced graphene oxide hybrid

This paper scrutinizes the fabrication of a chemiresistive type of acetylene (C2H2) gas sensor by synthesizing a silver (Ag)-loaded zinc oxide (ZnO)-reduced graphene oxide (Gr) hybrid via a facile chemical route. The as-synthesized hybrid was characterized in detail in terms of its structural, morphological and compositional properties. The physical properties of the hybrid exhibited a well-structured crystalline nature and mixed phases of Ag, Gr, and ZnO. The morphological characterization revealed that particle-like nanostructures of the ZnO and Ag mixer were well distributed and closely affixed onto the surface of thin-layer reduced graphene oxide sheets. At an optimum temperature of 150 °C, the 3 wt% Ag-loaded ZnO-Gr hybrid showed preferential detection of acetylene gas with a response value of 21.2 for 100 ppm gas concentrations. The fabricated sensor showed a low detection limit of 1 ppm, fast response and recovery times of 25 s and 80 s, respectively, and good repeatability. Experimental results also showed that the synthesized hybrid had a negligible relative humidity (RH) effect up to 31% RH, and then deteriorated significantly with increasing RH concentrations. After detailed examination, we conclude that an Ag-loaded ZnO-Gr hybrid could be an effective means of fabricating high-performance practical C2H2 sensors.