화학공학소재연구정보센터
Journal of Vacuum Science & Technology A, Vol.22, No.4, 1620-1624, 2004
Reaction intermediates in high temperature catalytic water formation studied with cavity ringdown spectroscopy
The rotational temperature and concentration of OH in the gas-phase outside a polycrystalline platinum catalyst has been measured using cavity ringdown spectroscopy. A mixture of H-2 and O-2 gases was used forming a stagnation point flow field outside the catalyst. The temperature of the catalyst was 1500 K, the total pressure in the chamber was 26 Pa, and the relative hydrogen concentration, alphaH(2), was set to 8%. From a Boltzmann plot, the rotational temperature was determined to be 775 +/- 24 K, and the amount of OH was calculated from that temperature to be 1.5 +/- 0.2 x 10(12) cm(-3), 6.5 mm. outside the catalyst. A similar experiment has also been performed using a polycrystalline palladium catalyst. However, due to lower amount of OH in the gas-phase outside the Pd catalyst, the number density could not successfully be determined. In this study we have shown that cavity ringdown spectroscopy successfully can be used to quantify desorbed intermediates within a catalytic reaction. (C) 2004 American Vacuum Society.