Progress and future challenges in controlling automotive exhaust gas emissions

Cu/Al2O3 catalysts for soot oxidation: Copper loading effect

“…NOx removal over a CRT catalyst is somewhat less than 10% [1], and an additional system for NOx removal is required. It is also reported that soot oxidation is strongly inhibited by the presence of SO 2 , so the CRT technology could not be introduced until low sulphur diesel fuel became available [1]. In addition, because of the high price of noble metals new active components based on non-noble metals are desired.…”

“…Among the different catalytic after-treatment technologies proposed for soot removal in diesel exhausts, the so-called CRT (Continuously Regenerating Trap) seems to be the most satisfactory at this moment [1], especially for heavy-duty diesel applications. This system consists of a Pt catalyst for NO oxidation to NO 2 , which is more oxidizing than NO and O 2 .…”

Effect of infiltration material on a LSM15/CGO10 electrochemical reactor in the electrochemical oxidation of propene

“…The present work studied the possibility of using an 11-layer porous single chamber electrochemical reactor for the oxidation of propene, a major Diesel exhaust emission component [14], without precious metal. In this work, the whole reactor was thought of as a catalytic filter with a porous composite electrode interfaced with a porous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 electrolyte for Diesel exhaust after-treatment.…”

Gold, an alternative to platinum group metals in automobile catalytic converters

“…However, in this case, the process will become uneconomic because of the amount of HCs consumed [19]. Also, the comparatively low temperature of the diesel exhaust, which is usually in the range 100-400°C, makes the reduction of NO x very difficult because of the low activities of conventional catalysts below 200°C [23].…”

“…However, in lean-burn engines, particularly diesels that can provide better fuel economy, direct reduction of NO x under lean conditions is practically impossible, although the oxidation of CO and HCs is fairly straightforward [19]. Control of NO x from lean-burn engines demands an additional approach which may entail the use of a NO x -storage catalyst (NSC) with periodic reductive regeneration, or selective catalytic reduction with ammonia (NH 3 -SCR) or hydrocarbons (HC-SCR) [19].…”