Effects of Pt Content on Room-Temperature Hydrogen Sensing Characteristics of Pt-SnO2 Nano-Composite Ceramics

Abstract

Abstract A series of Pt-SnO2 nano-mixtures with 0, 0.25, 1 and 2.5 wt% Pt separately were prepared using SnO2 nanoparticles and H2PtCl6. Through pressing and sintering, Pt-SnO2 nano-composite ceramics with Pt nanoparticles well dispersed have been successfully prepared from the nano-mixtures. Their resistance is found to increase monotonously and greatly with increasing Pt content, which is increased by three orders of magnitude when Pt is increased from 0 to 2.5 wt%. All those samples with a Pt content show distinct responses to hydrogen at room temperature, while their hydrogen sensitivity and their recovery time both decease dramatically with increasing Pt content. These results strongly suggest that Pt as a catalyst promotes oxygen chemisorption on SnO2 and the reaction between hydrogen and oxygen at room temperature. Pt thus has catalytic effects on both hydrogen and oxygen, which leads to quite complicated effects of Pt content on the room-temperature hydrogen sensing behaviors of semiconducting metal oxides.