Rhodium–Aluminum-Mixed Oxide Catalysts for Selective Reduction of NO x by Hydrocarbons

TLDR: In this article, the reduction activity increases with a decrease in the reducibility of rhodium, suppressing wasteful consumption of propene by the reaction with oxygen, and the addition of zirconium and gallium further enhanced the formation of those sites and increased the selectivity of NO x reduction.

Abstract: Rhodium—alumina-mixed oxides have been investigated as catalysts for selective catalytic reduction of NO x by propene, as a part of the R&D Project of Next Generation Catalysts Research Institute. The results indicated that the NO x reduction activity increases with a decrease in the reducibility of rhodium, suppressing wasteful consumption of propene by the reaction with oxygen. Coprecipitation method for the preparation of Rh-alumina catalysts was effective for the formation of the less-reducible rhodium sites, and the addition of zirconium and gallium further enhanced the formation of those sites and increased the selectivity of NO x reduction.