Transition metal-substituted hydrotalcite catalyst for removing nitrogen oxides from the exhaust gas of diesel engine by storage-reduction

Abstract

Disclosed herein is a transition metal-substituted hydrotalcite catalyst for removing nitrogen oxides using a storage-reduction method, in which a molar ratio of transition metal to magnesium is 0.2 or less, and a method of manufacturing a transition metal-substituted hydrotalcite catalyst for removing nitrogen oxides using a storage-reduction method, including the steps of preparing a hydrotalcite synthesis solution including transition metal precursors such that the molar ratio of transition metal to magnesium is 0.2 or less, and preferably 0.001 to 0.2; aging the synthesis solution; and hydrothermally treating the synthesis solution.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a transition metal-substituted hydrotalcite catalyst for removing nitrogen oxides from the exhaust gas of diesel engines by NOx storage and reduction (NSR).

[0003] 2. Description of the Related Art

[0004] In diesel engines, which are operated in the presence of excess oxygen to have high combustion efficiency, unlike gasoline engines, carbon monoxide, unburned hydrocarbons, and nitrogen oxides cannot all be removed using three-way catalysts because the concentration of oxygen included in the exhaust gas of diesel engines is high. For this reason, a selective catalytic reduction (SCR) method of removing nitrogen oxides by supplying urea as a reductant and an NOx storage and reduction (NSR) method of removing nitrogen oxides by reducing nitrogen oxides in an oxidation atmosphere after storing nitrogen oxides and then injecting fuel have been introduced. The NSR method can be easily app...

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