Chinese researchers uncover nickel-oxide structure that boosts low-nickel methane conversion

A team of Chinese scientists has demonstrated that a dynamic atomic structure forming on nickel oxide during partial oxidation of methane is responsible for the reaction’s high activity, overturning the long-standing belief that metallic nickel nanoparticles are the key catalysts. By preparing a Ni/Al₂O₃ catalyst with only 0.8 wt% nickel through a micro-emulsion technique, they observed 92 % conversion of methane and consistent syngas composition, matching the performance of a conventional 8 wt% nickel catalyst.

Post-reaction analysis showed virtually no metallic nickel, and a pure-phase NiO sample was inactive, indicating that the active site emerges only when the NiO surface reconstructs into a [Ni₁O₄Ni₄] unit on the (100) facet. Density-functional theory calculations estimated the activation energy for breaking a C-H bond on this motif at 12.5 kcal mol⁻¹, substantially lower than the 38.5 kcal mol⁻¹ for intact NiO and even below the 15.7 kcal mol⁻¹ for metallic Ni(111).

The findings highlight the importance of in-situ characterization and suggest that low-nickel catalysts could be engineered for cheaper, more efficient industrial syngas production. The work was led by Tao Zhang, Aiqin Wang, Xiaoyan Liu, Wei Liu, Tao Yang and Graham J. Hutchings and published in Nature Catalysis.