Enhanced methanol decomposition via metal-support interaction on Ni/CeO2(111) surface

This study explores the adsorption and reaction of methanol on the CeO2(111) and Ni/CeO2(111) surfaces, highlighting the essential role of metal-support interaction in methanol decomposition by a synergistic approach encompassing synchrotron radiation photoemission spectroscopy, X-ray photoelectron spectroscopy, infrared reflection and absorption spectroscopy, and temperature programmed desorption. Our findings reveal that Ni deposited on the CeO2(111) surface, followed by annealing to 700 K, leads to the formation of Ce-O-Ni mixed oxide as the dominant phase. The Ni2+ species facilitate the methoxy decomposition into CO and H2 within 300–430 K, with a small amount of formaldehyde also forming at the edge sites of ceria. Additionally, some methoxy adsorbed on the bare CeO2 surface migrates to the Ce-O-Ni mixed oxide, where they decompose into CO and H2 at 500–600 K, accompanied by a portion of the methoxy interacting with ceria to generate formaldehyde. Upon exposure to methanol at 500 K, the Ni2+ species are reduced to metallic Ni0, alongside the formation of coke and Ni3C, ultimately resulting in catalyst deactivation. However, reintroducing O2 reactivates these sites by oxidizing metallic Ni0 and Ni3C species. This study highlights the pivotal role of metal-support interaction in promoting oxygen transfer from ceria to Ni, thereby enhancing methoxy decomposition and significantly improving the performance of Ni-based catalysts for methanol decomposition into CO and H2.