Plasma-Switched Electrocatalytic Activity of Perovskite Oxide for Reversible Solid-Oxide Fuel Cells.

Perovskite-type heterogeneous catalysts are useful in diverse fields especially for the gas-solid catalysis system. However, because of the intrinsically low catalytic activity of the perovskite catalyst, the system's catalytic efficiency is usually low. In this study, we propose to rapidly switch the activity of the perovskite catalyst by plasma treatment. We report that by hydrogen plasma treatment for ∼13 min, a large number of nanoparticles with a small size appear on the surface of the La0.33Ca0.46Ce0.01Ti0.94Ni0.06O3-δ (LCCTN) perovskite, resulting in a significant enhancement of activity. Moreover, it is demonstrated that the exsolved nanoparticles can be successfully dissolved after oxygen plasma treatment for ∼18 min, primarily attributed to the strong driving force provided to the system. By alternative treatments of hydrogen and oxygen plasma, the LCCTN activity can be well switched. When applying LCCTN as a symmetrical solid-oxide fuel cell's electrode, the performance is prominently improved via switching the catalytic activity. At 900 °C, a peak power density of 1.1 W cm-2 is acquired for the plasma-switched LCCTN, which is more than 7 times higher than that of the pristine one. Also, the cell shows good reversibility. This work explores a way to switch the perovskite catalyst's activity and polarity in a rapid manner.