Temperature-independent TiO2-ZrO2 oxygen lambda sensor

The electromotive force (EMF) of a new type of YSZ-based planar oxygen sensor exposed to simulated automobile exhaust gas, with no air reference, was measured under different conditions. A sensor with two parallel Pt electrodes, one coated with Ti_0middot75Zr_0middot25O₂ (Ti-Zr) as a solid-state reference, was fabricated. The performance of this sensor was measured at different temperatures and lambda_s, i.e. the actual air/fuel ratio to that of stoichiometric value. The transition in EMF occurs around lambda=1. Also the amplitude of the transition between rich (lambda=0.8) and lean (lambda=1.2) measured at a temperature range of 350-650degC remains almost constant, indicating a temperature-independent performance.