Zeolite-supported ultra-small nickel as catalyst for selective oxidation of methane to syngas

Catalytic oxidation of methane to syngas is an important process, but efficient and stable catalyts remain in demand. Here dispersion of nickel on zeolites yields nickel oxide nanoparticles as small as 1.6 nm which act as selective and efficient catalysts for conversion of methane to syngas. The development of simple catalysts with high performance in the selective oxidation of methane to syngas at low temperature has attracted much attention. Here we report a nickel-based solid catalyst for the oxidation of methane, synthesised by a facile impregnation method. Highly dispersed ultra-small NiO particles of 1.6 nm in size are successfully formed on the MOR-type zeolite. The zeolite-supported nickel catalyst gives continuously 97-98% methane conversion, 91-92% of CO yield with a H-2/CO ratio of 2.0, and high durability without serious carbon deposition onto the catalyst at 973 K. DFT calculations demonstrate the effect of NiO particle size on the C-H dissociation process of CH4. A decrease in the NiO particle size enhances the production of oxygen originating from the NiO nanoparticles, which contributes to the oxidation of methane under a reductive environment, effectively producing syngas.