Selective Catalytic Reduction of NO by NH3 in Flue Gases over a Cu-V/Al2O3 Catalyst at Low Temperature

A novel copper-based catalyst with vanadium as a promoter has been synthesized and evaluated for its efficiency on the selective catalytic reduction of nitric oxide ( NO) in flue gases using ammonia (NH3) as a reductant in the temperature range of 50-5008 degrees C. The Brunauer-Emmett-Teller method, Energy Dispersive X-ray Spectrometry and Scanning Electron Microscopy have been used to characterize the catalysts developed. Effects of reaction parameters including temperature, space velocity, O-2 concentration, and the ratio of NH3 to NO on the selective catalytic reduction of NO by NH3 on the synthesized catalyst, as well as the chemical mechanisms and the side reactions involved have been examined. The catalyst shows high activity for NO conversion (89.6%) with a NH3/NO ratio of about 1 in the presence of oxygen (O-2) (similar to 3.0% v/v) at a temperature of 200 degrees C. At a temperature of 200 degrees C or below, only selective (desirable) catalytic reactions occur. NH3 was gradually oxidized to NO and nitrogen dioxide (NO2) at temperatures above 200 degrees C, and thus led to a low NO removal efficiency. NO conversion also increased with decreasing space velocity between 3,600 and 7,800 h(-1). Results indicate that the Cu-V/Al2O3 is a very promising and green catalyst for the elimination of NO using NH3 as a reductant in flue gases at low temperatures, and could be further developed as an efficient selective catalytic reduction (SCR)catalytic converter for removing NO from diesel vehicle exhausts.