Abstract
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► Pt/Fe/ZSM5 catalysts were tested for oxidation of NH3. ► Pt/Fe/ZSM5 catalysts showed good low-temperature activity for NH3 oxidation. ► Pt was exclusively dispersed on the Fe oxide through close Pt–Fe interactions. ► The degree of Pt–Fe interaction changed according to Fe loading amount.
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% NH3 conversion and 93% N2 selectivity at 175°C at the short contact-time of w/f=0.00012gmin/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 Al2O3 and SiO2. 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.