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

A series of very small grain Au/SnO2 composites were synthesized by a facile hydrothermal method. The microstructure of the Au/SnO2 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 SnO2 nanograins. The composites were porous material with large specific surface area. The sensors based on the Au/SnO2 composites showed high sensitivities and selectivity to n-butanol at low working temperature with fast response. Among these sensors, the 1.5 wt% Au/SnO2-based sensor shows the highest response (2662.8) to 100 ppm n-butanol with the response time of 35 s at 80 degrees C. The excellent low-temperature gas-sensing properties of the Au/SnO2 sensors can be ascribed to the synergetic effect of high surface energy of small SnO2 nanograins and catalysis of gold nanoparticles. Our study demonstrates that controlling the grain size of SnO2 and Au nanoparticle-assisted gas sensing are effective methods to improve the sensing properties of SnO2 at low working temperature. The 1.5 wt% Au/SnO2 composite is a potential low-temperature gas-sensing material for n-butanol detection.

Automated summary

A series of very small grain Au/SnO2 composites were synthesized using a simple hydrothermal method. The composites showed a hierarchical structure composed of 20-30 nm spherical nanoparticles, consisting of 8 nm Au cores and 5 nm SnO2 nanograins. The porous composites exhibited high sensitivity and selectivity to n-butanol at low working temperatures. The study suggests that controlling the grain size of SnO2 and using gold nanoparticles can improve the gas-sensing properties of SnO2 at low temperatures.