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.