Template-free synthesis of flower-like SnO2 hierarchical nanostructures with improved gas sensing performance

In the work, flower-like SnO2 hierarchical nanostructures assembled with numerous nanosheets were successfully prepared through a facile template-free hydrothermal route using SnSO4 as the tin source and water as the solvent. The process was simple, green, and effective. The obtained SnO2 products had uniform flower-like morphology, hierarchical nanostructures, and high specific surface area of 136.0 m(2)/g. The investigation of the experimental parameters demonstrated that the tetrapropylammonium hydroxide (TPAOH) played a crucial role in determining the structure and properties of the final products, which was acted as both the alkali source and morphology director. Ag/SnO2 nanostructures were also fabricated by a conventionally impregnation method, in which Ag nanoparticles with the size of 20-30 nm were uniformly grown into the surface of SnO2 product. The gas sensing tests indicated that both SnO2 and Ag/SnO2 sensors exhibited better gas sensing properties to n-butanol at low working temperature of 160 degrees C compared with the sensor based on the commercial SnO2 nanoparticles. As expected, the sensor based on the Ag/SnO2 product showed obviously enhancement in gas sensing performance. The growth process and gas-sensing mechanism were investigated based on the experimental results. The present protocol may be extended to the synthesis of other metal oxides with different nanostructures for more potential applications. (C) 2015 Elsevier B.V. All rights reserved.