Oxidation–reduction behaviour of highly dispersed ruthenium in RuNaY zeolite
Abstract
The thermal decomposition of the [Ru(NH3)6]3+ complex ion exchanged in a NaY zeolite followed by reduction in H2 at 623 K leads to highly dispersed Ru metal in the zeolitic pore system. X-ray diffraction techniques have been used to identify atomically dispersed Ru0 inside the sodalite cavity at the site II′. This high dispersion sample can be produced either by heating under high vacuum conditions or by heating under hydrolysing conditions where an H2O+H2 mixture is present in the system. The Ru0 in the sodalite cavity is not stable under oxidation as it is irreversibly removed upon the addition of O2 at ambient temperature and cannot be regenerated by subsequent reduction in H2. Na+ ions within the zeolite always occupy sites I′ and II and are generally unaffected by the redox chemistry involving the ruthenium.