The Effect of Hydrothermal Aging on NOₓ Reduction by Urea SCR/DPF Catalyst

尿素 SCR/DPF 触媒の NOx 浄化性能に対する水熱劣化の影響

Urea SCR on Diesel Particulate Filter (SCR/DPF) is important technology for reduction of NOₓ and PM, and is required to meet the emission and fuel economy standards which are becoming more stringent in the future. However, the SCR/DPF catalyst performance deteriorates due to exposure in severe environment. In this study, to investigate the catalyst degradation mechanism, we focused on hydrothermal degradation among many factors of the SCR/DPF degradation. Several hydrothermal aging conditions were selected. NOₓ reaction, NH₃ and NO oxidation rates were measured and amount of ion-exchanged Cu and ionexchangeable sites were determined by H₂-TPR and ²⁹Si NMR, respectively. We found that NOₓ reaction rate increased with increasing the amount of ion-exchanged Cu. At the test temperature of 400°C and over, no correlation was found between the NOₓ reaction rate and the amount of ion-exchanged Cu. Under the temperature conditions of 300°C or less where the diffusion has no influence on the NOₓ reaction rate, NOₓ reaction rate is proportional to the amount of ion-exchanged Cu.尿素SCRDPF は厳しくなる排気,燃費規制への対応技術として重要である.しかし,自動車触媒は厳しい環境で使用されるため触媒は劣化し性能低下が起こる.本報では,劣化の中でも水と熱に着目し,SCRDPF 触媒に対して劣化条件を変化させてNOx 浄化率評価を行うとともに,触媒性能劣化メカニズムを検討した.


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  • Accession Number: 01673541
  • Record Type: Publication
  • Source Agency: Japan Science and Technology Agency (JST)
  • Files: TRIS, JSTAGE
  • Created Date: Jun 25 2018 5:18PM