Facile Synthesis of Pt-Functionalized SnO[sub 2] Hollow Hemispheres and Their Gas Sensing Properties

Abstract

This work presents a new route for enhancing the sensor response kinetics of macroporous films. Well-ordered arrays of hollow hemispheres, functionalized with catalytic Pt, were synthesized using colloidal templating and cosputtering, followed by subsequent heat-treatment. The diameter and shell thickness of the Pt-functionalized hollow hemispheres were 800 and 25 nm, respectively. High resolution transmission electron microscopy analysis indicates that catalytic Pt nanoparticles, with size of a few nanometers, coat the top surface of hemispheres, enabling chemical reactions to proceed at lower temperatures. Sensors composed of Pt-functionalized hollow hemispheres show attractive gas sensing characteristics, such as reduced operation temperature combined with improved sensitivity ( to 250 ppm ), reduced baseline resistance, and enhanced response/recovery properties compared to sensors using pristine hollow hemispheres at an operating temperature of .