Aftertreatment Protocols for Catalyst Characterization and Performance Evaluation: Low-Temperature Oxidation, Storage, Three-Way, and NH3-SCR Catalyst Test Protocols

Analysis of Ion-Exchanged ZSM-5, BEA, and SSZ-13 Zeolite Trapping Materials under Realistic Exhaust Conditions

“…After the 30-min storage, the reactant gases are turned off, and the sample is quickly heated to 600 • C. During this portion of the experiment the HCs desorb from the sample, and some of them react to form CO and CO 2 . As suggested by the protocol [38,39], the release profile is described by three characteristic temperatures. The first is the temperature of 10% release (T10), i.e., the temperature where 10% of the observed desorbed HCs were released.…”

“…Characterization of HC and NOx trapping was conducted utilizing a storage protocol developed by the U.S. DRIVE Advanced Combustion and Emissions Control Technical Team [38,39]. Quartz wool and 100 mg of trapping material were loaded into an 8 mm diameter quartz reactor U-tube to create a plug-flow bed with one K-type thermocouple placed at the center of the bed and another K-type thermocouple approximately 1 cm above the bed to record bed and inlet temperatures, respectively.…”

“…These samples were then re-evaluated according to the procedure outlined above. According to the low-temperature storage protocol [38,39], this time and temperature is intended to stress the materials to a similar level that would be expected at the end of their full-useful-life. Following the degreened evaluations of the samples, the most promising materials were hydrothermally aged at 800 • C for 50 h in [O 2 ] = 12%, [CO 2 ] = 6%, and [H 2 O] = 6% with Ar balance.…”

“…These samples were then re-evaluated according to the procedure outlined above. According to the low-temperature storage protocol [38,39], this time and temperature is intended to stress the materials to a similar level that would be expected at the end of their full-useful-life.…”

“…With that in mind, we present an evaluation of nine zeolite-based trapping materials utilizing a flow reactor protocol developed by a collaboration of industry, national laboratories, and academic researchers [38,39] to mimic realistic lean-burn automotive exhaust. As described in detail below, this protocol includes the opportunity to simultaneously trap CO, NOx, and three HCs representative of those found in automotive exhaust: ethylene (short-chain alkenes), toluene (aromatics), and decane (long-chain alkanes).…”