The research team of Tokyo University’s Institute of Industrial Science clarified the mechanism that deteriorates the catalytic property of potassium carbonate used to purify soot emitted from a diesel engine under the leadership of Associate Professor Masaru Ogura. Potassium carbonate can be used as a catalyst to purify soot emitted from a diesel engine should it be combined with sodalite that is a kind of zeolite, but it separates from sodalite and deteriorates its catalysis as the period of service of a diesel engine grows longer. Measures to prevent the deterioration have been strongly desired.
The research team studied the deterioration mechanism and found that the depuration likely deteriorates because the calcium ion of potassium carbonate combined with sodalite changes to metallic potassium or evaporates as potassium oxide. Based on the research findings, the research team plans to develop a material with stronger ability to retain potassium ion. Emissions from a diesel engine contain hydrocarbon, nitrogen oxide, and carbon monoxide in addition to soot. While a platinum catalyst is effective for all of these substances, potassium carbonate can purify only soot. However, should potassium carbonate can replace platinum for the purification of soot, it will be possible to halve the required amount of platinum to purify emissions from a diesel engine.