SnO2 clusters embedded in TiO2 nanosheets: Heterostructures and gas sensing performance

SnO2 clusters were embedded in superior thin TiO2 nanosheets to form heterostructures via a two-step solvothermal synthesis. Superior thin TiO2(B) nanosheets were firstly prepared, in which these nanosheets exhibited homogeneously sheet structure without aggregation. After deposition of SnO2 clusters, the mixture phase consisted of anatase and TiO2(B) was obtained even though the nanosheet morphology remained unchanged. The ratio of SnO2 and TiO2 was adjusted to get enhanced gas sensing performance. The gas sensing activity of samples for volatile organic compounds including acetone, ethanol and triethylamine was tested. Results indicates that SnO2/TiO2 heterostructure with an optimal SnO2 weight ratio of 10% is remarkably responsive to acetone, ethanol and triethylamine. Especially, the response time to triethylamine is only 10 s. In the case of 2 ppm, the sample still revealed a significant response to triethylamine. The enhanced sensing performance has to ascribed to the significant increase of reactive active sites by loading SnO2 clusters. In addition, ultra-thin morphology and mixed phase composition of TiO2 also enhance the property of the composite. This work supplied an idea for the preparation of SnO2 based gas sensors.