In order to improve the gas-sensing performance at low temperature, binary Au/SnO2 species were used to modify WO3 nanoplates, i.e., Au/SnO2@plate-WO3 composites, which were synthesized by in-situ reducing HAuCl4 with SnCl2 adsorbed on the surfaces of WO3 nanoplates derived via an intercalation and topochemical conversion route. XRD, XPS, SEM, TEM-UV vis DR spectra were used to characterize the samples. The gas-sensing properties of the samples were evaluated using H2S as target gas. The Au/SnO2 nanoparticles with small sizes (several nanometers) are uniformly anchored on the surfaces of WO3 nanoplates. The response of the 0.5%Au/SnO2@plate-WO3 sensor to 10 ppm H2S is up to 220 at 50 degrees C, 28 times higher than that of the plate-WO3 sensor. The optimal operation temperature of the plate-WO3 and Au/SnO2@plate-WO3 sensor for H2S detection is about 150 degrees C. The responses of the Au/SnO2@plate-WO3 sensor to 100 ppm of CO, SO2, H-2, CH4 and organic vapors are negligibly low (1.2-8.0) at low temperatures. The possible explanation for the high selectivity and response in H2S detection at low temperatures can be the synergistic effect of the binary Au/SnO2 nanoparticles and ultra-thin WO3 nanoplates in adsorption, reaction and diffusion of the gas molecules. (C) 2014 Elsevier B.V. All rights reserved.