Effect of Co3O4 and CeO2 Infiltration on the Activity of a LSM15/GDC10 Highly Porous Electrochemical Reactor

The reduction of air pollution has become an international concern over the last ten years because of increases in emissions from mobile and stationary sources. Among these sources, volatile organic compounds (VOC) represent a serious environmental problem, together with NOx, SOx and particulate matter, which lead to the formation of ozone in urban and regional areas [1]. The electrocatalytic activity of a porous electrochemical reactor, made of La_0.85Sr_0.15MnO_3±δ (LSM) as electrode and Ce_0.9Gd_0.1O_1.95 (GDC) as electrolyte, was studied for the electrochemical oxidation of propene (C₃H₆), a major VOC component of Diesel engine exhausts, over a wide range of temperatures. The entire reactor was thought as a highly porous catalytic filter for a possible application in a Diesel exhausts purification system.

The porous reactor was used as a backbone for the infiltration of Co₃O₄ and Co₃O₄/CeO₂. The effect of the infiltration on the electrochemical properties and catalytic activity of the reactor was investigated by electrochemical impedance spectroscopy (EIS) and gas analysis.

Figure 1 shows the SEM cross-section micrograph of the electrochemical reactor made of 11 alternating layers of electrode (LSM) and electrolyte (GDC).

Figure 2 shows the Nyquist plot of the impedance spectra  of Co₃O₄ infiltrated backbone recorded at OCP with 10% O₂ and 10% O₂ + 1000 ppm C₃H₆, 2 L/h, 400 °C.

[1] R. Atkinson, Atmospheric Chemistry of VOCs and NOx, Atmos Environ. 34 (2000) 2063;