Metal-support interaction refinement regulation by atmosphere heat induction technology and its influence mechanism on catalytic performance

Abstract

Metal-support interaction (MSI) has been widely recognized to be playing a pivotal role in regulating heterogeneous catalytic activity. In this work, Rh-CexZr1-xO2 (Rh-CZ) interaction was fine-adjusted by atmosphere heat induction technology, and the effects of induction factors on MSI and catalytic performance were systematically and deeply studied. The structure-activity relationship results showed that diverse atmospheres induced significantly different Rh microchemical states and MSI, thus resulting catalytic activity varies widely. H2-induced can not only obtain more suitable MSI, but also make Rh species in a highly active state (smaller particle size and lower valence state), which can prompt Rh more evenly dispersed on the surface of CZ and expose more active sites, and facilitate the activation and adsorption of reactants, thus showing better catalytic activity. Rh/CZ-H2 presented a 30–50 °C reduction in light-off temperature for the reactants and a wider air-fuel ratio window, and still showed the best catalytic activity even after aging. Meanwhile, the strong MSI constructed after air-induced prevented the sintering of Rh species and maintained the catalytic activity of Rh/CZ-Air after aging (no decrease in activity). In addition, Rh/CZ-N2 produced by N2-induced lost the protection of Rh-CZ MSI and resulted in larger Rh particle size before and after aging, so the number of active sites over Rh/CZ-N2 decreased significantly, and the activity and stability were the worst. This study provides an insightful understanding of MSI modulation and its influence mechanism on catalytic performance, as well as provides a reference for industrial applications.