Reduced graphene oxide decorated with CuO-ZnO hetero-junctions: towards high selective gas-sensing property to acetone

The development of an efficient gas sensor device with high sensitivity, good selectivity and excellent stability is necessary to satisfy future societal and environmental needs. Herein, a one-step hydrothermal strategy is developed for the synthesis of a CuO-ZnO/reduced graphene oxide rGO) ternary composite. Compositional, morphological and structural analyses demonstrate the successful anchoring of nanoscale p-n junctions between CuO and ZnO nanoparticles on rGO sheets. The obtained CuO-ZnO/rGO ternary composite exhibits outstanding sensing properties to acetone the gas response value reaches from 9.4 to 10 ppm of acetone), almost 1.5 times and 2.0 times higher than CuO-ZnO and ZnO/rGO, respectively. More significantly, the ternary composite presents weaker sensing performance to ethanol and showing superior performance for effectively distinguishing acetone and ethanol. Moreover, the ternary composite exhibits good selectivity towards acetone vapor about 6-41 times greater than that of other tested vapors). These findings highlight beneficial synergistic effects originated from large numbers of valid p-n junctions of CuO-ZnO and superior substrate characteristics of rGO sheets.