Pt/SiO2촉매상에서 H2에 의한 저온 N2O 제거반응

Abstract

The present work has been devoted to the catalytic reduction of <TEX>$N_2O$</TEX> by <TEX>$H_2$</TEX> with <TEX>$Pt/SiO_2$</TEX> catalysts at very low temperatures, such as <TEX>$110^{\circ}C$</TEX>, and their nanoparticle sizes have been determined by using <TEX>$H_2-N_2O$</TEX> titration, X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM) measurements. A sample of 1.72% <TEX>$Pt/SiO_2$</TEX>, which had been prepared by an ion exchange method, consisted of almost atomic levels of Pt nanoparticles with 1.16 nm that are very consistent with the HRTEM measurements, while a <TEX>$Pt/SiO_2$</TEX> catalyst possessing the same Pt amount via an incipient wetness technique did 13.5 nm particles as determined by the XRD measurements. These two catalysts showed a noticeable difference in the on-stream <TEX>$deN_2O$</TEX> activity maintenance profiles at <TEX>$110^{\circ}C$</TEX>. This discrepancy was associated with the nanoparticle sizes, i.e., the <TEX>$Pt/SiO_2$</TEX> catalyst with the smaller particle size was much more active for the <TEX>$N_2O$</TEX> reduction. When repeated measurements of the <TEX>$N_2O$</TEX> reduction with the 1.16 nm Pt catalyst at <TEX>$110^{\circ}C$</TEX> were allowed, the catalyst deactivation occurred, depending somewhat on regeneration excursions.