A step closer to replacing platinum in catalytic converters

The research group of Masaru Ogura, an associate professor at the Institute of Industrial Science, University of Tokyo (www.u-tokyo.ac.jp), has clarified the degradation mechanism and the role potassium carbonate plays in the catalyst systems used for reducing soot from the exhaust of diesel engines. Based on its studies, the group has proposed a new catalyst system with enhanced tolerance to catalyst degradation. In 2008, Ogura and coworkers, in collaboration with Mitsubishi Motors Corp., discovered that the zeolite sodalite (Na4Al3(SiO4)3), in combination with K2CO3 could be used for reducing soot emissions. But this K2CO3/sodalite system lost its catalytic activity after long-term driving tests due to the separation of potassium carbonate from sodalite. Ogura analytically clarified that the separation of potassium carbonate was caused by the metallization of potassium and the vaporization of potassium through oxidation. Now, Ogura has discovered that K2CO3 supported on Na-type nepheline (K2CO3/Na-nepheline) has enhanced tolerance against water washing after heat treatment at 800°C. This system maintains its catalytic function on the purification of soot in diesel exhaust emissions after water washing of the catalyst system. Today,…