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.