Catalytic NO–CO–C3H6–O2 reactions over hydrothermally stable Rh-supported ZrP2O7 catalyst

Abstract

A novel and facile hydrothermal synthetic route for ZrP2O7 from ZrO(OH)2 and H3PO4 has been developed to use this as an active support for Rh catalyst. Temperature-programmed reactions of mixtures of NO, CO, C3H6 and O2 with a stoichiometric A/F ratio (14.6) were investigated over Rh-supported ZrP2O7 catalyst. A lower amount of Rh (0.4 wt.%) loaded to ZrP2O7 exhibited satisfactory light-off at lower temperature (T50% = 312 °C) with a steep rise in conversion efficiency after ageing the catalyst at 900 °C for 25 h in a stream of 10% H2O/air. Rh particle growth was not so significant even after 500 h of ageing at 900 °C in the stream of 10% H2O/air, which is one of the reasons for exhibiting adequate catalytic activity of this catalyst after long-term exposure in H2O/air. Reducibility of Rh oxide was enhanced substantially by this support which is believed to be the key factor for exhibiting good catalytic activity after ageing in an oxidizing environment. This newly developed Rh/ZrP2O7 catalyst with minimum Rh loading, having high thermal stability up to 1200 °C along with outstanding capacity to resist sintering at high temperature, has the potential to serve as a new generation deNOx catalyst.