Template-free synthesized hollow NiO-SnO2 nanospheres with high gas-sensing performance

Hollow NiO-SnO2 nanospheres have been fabricated via a simple one-pot template-free method. The synthesis is based on solvothermal treatment of stannate and nickel nitrate as the precursor in a mixed solvent of heptane-ethanol. The hollow nanospheres show diameters of about 200-300 nm with the wall thickness of about 50 nm, and the shell consists of numerous small nanoparticles. The gas sensor based on hollow NiO-SnO2 nanospheres exhibits high response and quick response-recovery to NH3, which are much better compared with sensors based on solid NiO-SnO2 nanospheres. The enhanced sensor performances are attributed to the larger surface area and fast gas diffusion. (C) 2012 Elsevier B.V. All rights reserved.