Acetylene gas sensing properties of silver nanoparticles decorated ZnO morphologies with reduced graphene oxide hybrids

In the current work, in order to investigate the acetylene (C₂H₂) gas sensing behaviors of different ZnO morphologies; ZnO nanoparticles (NPs), hierarchical ZnO (Hrc), silver (Ag)-loaded ZnO NPs-reduced graphene oxide (Ag/ZnO NPs-rGO) hybrid and Ag-loaded ZnO Hrc-rGO (Ag/ZnO Hrc-rGO) hybrid were successfully synthesized via hydrothermal and chemical method. Addition of small amount of additives (Ag: 3 wt%; rGO: 12 wt%) with the pristine ZnO has boosted the sensing performance within the temperature range of 25-300°C, in which Ag/ZnO NPs-rGO hybrid showed the best result among the tested samples. Low operating temperature (150°C), high response magnitude (21.2 to 100 ppm gas concentration) and fast response/recovery time (25/80 sec) of the Ag/ZnO NPs-rGO hybrid might be attributed to the specific surface area, crystalline quality, surface defects and uniformity of the ZnO NPs, and the active catalytic effect of Ag and rGO with ZnO NPs in the hybrid.