TAŞDEMİR, H. Mehmet Gazi Üniversitesi - Mühendislik Fakültesi - Kimya Mühendisliği Bölümü, Turkey , YAŞYERLİ, Nail Gazi Üniversitesi - Mühendislik Fakültesi - Kimya Mühendisliği Bölümü, Turkey

THE INVESTIGATION OF UREA DECOMPOSITION OVER Ag/ALUMINA CATALYSTS

16700

The NOx gases which are released from diesel vehicles can be reduced to N2 gas with selective catalytic reduction (SCR) reactions. The yield of these reactions are majorly related to the reducing agent. Both urea and its’ decomposition/hydrolysis compounds which are isocyanic asid (HNCO) and ammonia (NH3) can be used SCR reactions. Therefore, urea is an attractive reducing agent recently. Ag/Al2O3 catalysts have an important role for NOx reduction. The decomposion and hydrolysis compounds of urea on the %1 Ag/Al2O3 and %2 Ag/Al2O3 catalysts which are prepared by sol-gel method were investigated by using FTIR. The experimental studies were carried out between 100-400°C temperature in the presence of helium. As a result of the analyses of FTIR spectra, NH3, NH4 ^+, -CNO, melamine and CO2 were dedected as the decomposition and hydrolysis compounds of urea on the catalysts. Besides that, OH, CH, NH and C=O stretching vibration bands were also observed. NH4 + compound was not observed at any temperature on the %1 Ag/Al2O3 catalyst however, it was observed at the temperatures of 100 and 250 °C on the %2 Ag/Al2O3 catalyst. Ammonia, which is a decompositon and hydrolysis compound of urea, was observed on both catalysts at all temperatures and times. Isocyanate (-CNO), which is a decompositon compound of urea, gave its most intensive peak at the temperature of 200°C on %1 Ag/Al2O3 catalyst and at the temperature of 250°C on %2 Ag/Al2O3 catalyst.

523

Ag , Alumina Catalysts , Decomposition of Urea , FTIR

Journal Of The Faculty Of Engineering an‎d Architecture Of Gazi University

532