A novel low temperature gas sensor based on Pt-decorated hierarchical 3D SnO2 nanocomposites

A novel gas sensor composed of Pt nanoparticles-decorated hierarchical SnO2 nanostructures (Pt-SnO2) was synthesized via a facile dipping-precipitation strategy. Pt nanoparticles with small sizes (avg. 4 nm) were successfully dispersed onto our pre-synthesized 3D hierarchical SnO2 nanoflowers supports by using lysine as both capping and linking agents. The morphology, structure and composition of the as prepared samples were characterized by means of field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Comparisons of the gas sensing performance between pure SnO2 and Pt-SnO2 nanocomposites revealed that after supporting Pt nanoparticles, the decorated sensor not only got an optimal working temperature of as low as 100 degrees C, but also exhibited faster response and recovery speeds and higher response than the pristine one at such low temperature. Moreover, good selectivity and excellent stability were also shown for the hybrid sensor. Sensing mechanisms were illustrated to help explain the strong spillover effect of the Pt nanoparticles and the Schottky barriers at the interface of metal and semiconductor, both of which facilitated the low temperature sensing performance. The Pt-SnO2 sensors are considered to be a promising candidate for trace environmental gas detections in practical use. (C) 2016 Elsevier B.V. All rights reserved.