Immortal catalytic activity for cleaning up automotive emissions; Intelligent catalyst

Nishihata, Yasuo; Tanaka, Hirohisa*

Catalytic converters are widely applied to control automotive emissions, such as nitrogen oxides, carbon monoxide and unburned hydrocarbons. In actual catalysts, however, the catalytic activity deteriorates due to the particle growth of precious metals during vehicle use. An ageless catalyst is a kind of philosopher's stone in automotive engineering. Referring to the wisdom of ancient Indian philosophy and medical science, Ayur Veda, we have developed a new self-regenerating perovskite-based catalyst. The perovskite catalyst, LaFeCoPdO, regenerates itself without any auxiliary treatment, in direct reaction to the natural fluctuation between reductive and oxidative atmospheres in the exhaust gas from state-of-the-art gasoline engines. As palladium reversibly moves back and forth between inside and outside of the perovskite crystal, the particle growth of palladium can be suppressed. Such a self-regeneration provides new insight into the development of future automotive catalyst, as an intelligent catalyst.