Removal of Nitrogen Oxides Using Nanosized Catalysts Prepared by Dry Mechanical Coating Technique

Abstract

Nitrogen oxides (NOx) are the key air pollutants emitted by mobile and stationary sources, and are a major cause of adverse health and environmental effects. One promising alternative material to conventional noble metal-based catalysts for NOx emission control is the group of transition metal oxides, in particular, CuO. In this study, well-dispersed CuO and CuO/Al2O3 nanocatalysts coated onto durable Al2O3 fiber substrates were assessed for NO conversion efficiency. The resultant composite materials had high surface area with good dispersion for enhanced NO conversion. Operating parameters, including nanocatalysts loading and temperature, were investigated for their effects on the catalytic performance for NO conversion. The experimental results showed that the activity of the catalysts is strongly related to the loading amount and the degree of dispersion of CuO nanoparticles. The binary CuO/Al2O3 system yielded a higher NO conversion efficiency than the system consisting of CuO alone. Small amounts of Al2O3 employed in the binary system resulted in better dispersion, and subsequently the achievement of higher NO conversion efficiency. The stability of the catalysts was demonstrated over a wide range of temperatures, and proved satisfactory for the harsh environment of the exhaust system. However, sintering and alloying effects that result in a decrease in surface area may potentially lower the catalytic activity at high temperatures.