Seong Ho Lee

Oxidation of ammonia to nitrogen over Pt/Fe/ZSM5 catalyst: Influence of catalyst support on the low temperature activity

In this study, Pt/Fe/ZSM5 catalysts were applied to oxidation of ammonia, where the catalysts showed good low-temperature activity (≤ 200°C) for converting ammonia into nitrogen. With 1.5% Pt/0.5% Fe/ZSM5 catalyst, we could obtain 81% NH(3) conversion and 93% N(2) selectivity at 175°C at the short contact-time of w/f=0.00012 g min/mL. Through the characterization studies using high-resolution transmission electron microscopy (HRTEM) and X-ray spectroscopies (XRD, XPS), we could find that the active species was collaborating Pt/Fe species, which structure and activity were largely influenced by support material - in a positive way by ZSM5, rather than by Al(2)O(3) and SiO(2). When using ZSM5 as the support material, Pt was highly dispersed exclusively on the Fe oxide, and the valence state and dispersion of Pt changed according to Fe loading amount.

Development of highly compact PROX system for PEMFC fuel processor

Abstract A preferential oxidation (PROX) reactor for a 10 and 25-kWe polymer electrolyte membrane fuel cell (PEMFC) systems is developed. Pt-Ru/Al 2 O 3 catalyst powder with a size of 300-600 μm is used for the PROX reaction. To minimize pressure drop and to avoid hot spots in the catalyst bed, the reactor is designed as a multi-stage, multi-tube system. The steady and transient performances were investigated using gasoline-reformed gas. A newly designed heat exchanger type PROX system with non-pellet type coated catalyst was also designed and applied to a small-scale PROX system.