Synthesis of Au/SnO2 composites and their sensing properties toward n-butanol

A series of very small grain Au/SnO 2 composites were synthesized by a facile hydrothermal method. The microstructure of the Au/SnO 2 composites were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy, and nitrogen adsorption–desorption experiment. The composites were composed of 20–30 nm spherical nanoparticles, which are hierarchical structure composed of 8 nm Au cores and 5 nm SnO 2 nanograins. The composites were porous material with large specific surface area. The sensors based on the Au/SnO 2 composites showed high sensitivities and selectivity to n -butanol at low working temperature with fast response. Among these sensors, the 1.5 wt% Au/SnO 2 -based sensor shows the highest response (2662.8) to 100 ppm n -butanol with the response time of 35 s at 80 °C. The excellent low-temperature gas-sensing properties of the Au/SnO 2 sensors can be ascribed to the synergetic effect of high surface energy of small SnO 2 nanograins and catalysis of gold nanoparticles. Our study demonstrates that controlling the grain size of SnO 2 and Au nanoparticle-assisted gas sensing are effective methods to improve the sensing properties of SnO 2 at low working temperature. The 1.5 wt% Au/SnO 2 composite is a potential low-temperature gas-sensing material for n -butanol detection.