Construction of nanoflowers-like Au@ZnO/ZnS/SnO₂ heterostructure for conductometric cyclohexanone detection

Au decorated ZnO/ZnS/SnO2 nanostructures were prepared and used as sensing materials for cyclohexanone gas detection. Ternary ZnO/ZnS/SnO2 nanostructures were fabricated after hydrothermal method, sulfuration and calcination at a specific temperature. The achieved heterostructures are in the shape of nanoflower and then decorated with different amounts of Au nanoparticles (NPs). The results of gas sensing measurements demonstrate that construction of heterojunctions between components and functionalization with Au NPs could remarkably enhance the gas sensing performance toward cyclohexanone gas. Especially, Au-2@ZnO/ZnS/SnO2 gas sensor exhibits the highest response (497-100 ppm), fast response/recovery speed (1/50 s), low theoretic limit of detection (1.1 ppb) and better selectivity (S-cyc./S-other > 15.2) at 260 degree celsius, 25% RH (similar to 24 degree celsius). The details of heterojunctions between the three components and spillover effect of Au NPs-related sensitization mechanism are discussed finally.