Integrated in situ spectroscopic studies on syngas production from partial oxidation of methane catalyzed by atomically dispersed rhodium cations on ceria.

Abstract

Catalytic reforming of methane to produce syngas is an important strategy for producing value-added chemicals. The conventional reforming catalyst relies on supported nickel nanoparticles. In this work, we investigated singly dispersed Rh cations anchored on a CeO2 catalyst (Rh1/CeO2) for high activity and selectivity towards the production of syngas via partial oxidation of methane (POM) in the temperature range of 600-700 °C. The yields of H2 and CO at 700 °C are 83% and 91%, respectively. The anchored Rh1 atoms on CeO2 of Rh1/CeO2 are in the cationic state, and on an average each Rh1 atom coordinates with 4-5 surface lattice oxygen atoms of CeO2. Compared to inert CeO2 for POM, via the incorporation of single-atom sites, Rh1 modifies the electronic state of oxygen atoms proximal to the Rh1 atoms and thus triggers the catalytic activity of CeO2. The high activity of single-atom catalyst Rh1/CeO2 suggests that the incorporation of single atoms of transition metals to the surface of a reducible oxide can modulate the electronic state of proximal anions of the oxide support toward forming an electronic state favorable for the selective formation of ideal products.