Pt catalytic effects on a resistive oxygen sensor using Ce_0.9Zr_0.1O₂ thick film in rich conditions

Abstract

In this study, we investigated the Pt catalyst effects on two structures through loading a Pt catalyst onto a resistive oxygen sensor using Ce_0.9Zr_0.1O₂ thick film. We used (1) Ce_0.9Zr_0.1O₂ thick film with a Pt/alumina layer, and (2) Pt/Ce_0.9Zr_0.1O₂ thick film, in which Pt catalysts were prepared by heating platinum chloride. In the case of sensor structure (1), it became clear that the Pt/alumina layer with a Pt concentration of 40 wt% was the most effective in the Pt/alumina layers fabricated in this study, where R(λ = 0.6)/R(λ = 1.4) was 0.0099, and R(λ = 0.6)/R(λ = 1.4) of the 40 wt% Pt/alumina layer decreased with decreasing temperature. In the case of sensor structure (2), the minimum values of R(λ = 0.6)/R(λ = 1.4) at 600 and 700°C were the same at 0.035. The ultrasonic treatment in the Pt loading process improved R(λ = 0.6)/R(λ = 1.4) to 0.02. The Pt particle size in this study was in a range from 20 to 100 nm because of the high temperature annealing in the Pt loading process.