| 摘要 |
<p>An ammonia (NH 3) precursor composition (I), for use in selective catalytic reduction (SCR) of nitrogen oxides with NH 3 to purify oxygen-containing automobile exhaust gas, where (I) is catalytically decomposed to NH 3 in the main and auxiliary exhaust gas streams, consists of a mixture of formamide (HCONH 2) and water. An independent claim is included for a corresponding automobile exhaust gas purification method, including reduction of nitrogen oxides using (I) as above and catalytic oxidation after the SCR catalyst reaction to prevent secondary emission, where (a) a highly active catalyst is used for decomposition of formamide to NH 3 for the SCR reaction and (b) an oxidation catalyst ('barrier catalyst') (7) and/or a combined oxidation catalyst and particle filter (3) is used after the SCR catalyst (6) for inhibiting undesirable emission of formamide and intermediates from its decomposition.</p> |
