Investigation of NH3 and no adsorption over Cu/SAPO-34 and Cu/AlOo3 catalysts for NH3–SCR system

In this study, Copper supported on SAPO-34 molecular sieves or alumina is prepared via an incipient wetness impregnation method for ammonia selective catalytic reduction (NH_3-SCR). These NH_3-SCR catalysts are characterized by pulse chemisorption, temperature-programmed reduction (TPR), and temperature-programmed desorption (TPD) with three different conditions (NH_3, NO, combined NH_3-NO) to evaluate the adsorption of ammonia and nitric oxide. Cu/SAPO-34 catalyst has shown higher ammonia adsorption capacity compared to Cu/Al_2O_3 catalyst. The Cu/SAPO-34 adsorption is enhanced due to the strong acidity and high surface area of SAPO-34 molecular sieves. NO adsorption peaks over both catalysts are small (for NO-TPD) and these peaks become broader when a combined NH_3-NO is introduced to the system. However, Cu/SAPO-34 & Cu/Al_2O_3 surface area and acidity are decreased dramatically comparing to SAPO-34 and Al_2O_3 supports. These observations are verified by TPR and CO chemisorption. The formation of bulk copper aluminate over (Cu/Al_2O_3) surface and CuO over (Cu/SAPO-34) surface may block the acid sites. Moreover, the metal dispersion over both catalysts is below 10%. Based on the comparison, various factors could influence the adsorption of NH_3 and NO over the catalyst surface. The high specific surface area could provide abundant adsorption sites, which increase the adsorption capacity. Also, the multiple locations of acid spots along a wide temperature range, which are seen over Cu/SAPO-34, could continuously maintain the adsorption of NH_3 and NO even at elevated temperature.

Name thesis:degree_name

Master of Science in Chemical Engineering - (M.S.)

Discipline thesis:degree_discipline

Chemical, Biological and Pharmaceutical Engineering

Year

2017

Author dc:creator

• Rawah, Basil

Contributors dc:contributor

• Xianqin Wang
• R. P. T. Tomkins
• Robert Benedict Barat

• NH3 adsorption
• NO adsorption
• Copper
• Chemical Engineering

Repository record dc:identifier

https://digitalcommons.njit.edu/theses/27

OAI identifier oai:identifier

oai:digitalcommons.njit.edu:theses-1026