Deactivation Mechanism of NOx Storage-Reduction Catalyst and Improvement of Its Performance

摘要

(1) An analysis of the effect of TiO_2 on sulfur desorption led to the new discovery of its effect of promoting the decomposition of sulfates in the Vicinity of the contact surface. This discovery led to the development of a finer-grained form of TiO_2. (2) Reforming the Rh/ZrO_2 catalyst by means of additives improved its basicity and heat resistance, as well as its hydrogen generating characteristics. Based on these two new technologies, a new catalyst with superior sulfur desorption performance was developed, and NOx storage performance was improved by 50%. This catalyst was commercialized with further improvements in October, 1999.