A Decrease in NiO-MgO Phase Through Its Solid Solution Equilibrium with Tetragonal (La1-zSrz)(2)Ni1-yMgyO4-delta: Effect on Catalytic Partial Oxidation of Methane

作者：Yin Xiong; Hong Liang^*; Gong Zhengliang

来源：Journal of Nanomaterials, 2012, 263568.

DOI：10.1155/2012/263568

Calcination of an oxide mixture consisting of 0.4 La2O3, 0.2 SrCO3, (1 - x)NiO, and xMgO at 800 degrees C results in an equilibrium between tetragonal (La1-zSrz)(2)Ni1-yMgyO4-delta phase and NiO-MgO phase. Forming rock-salt NiO-MgO facilitates the NiO to join the tetragonal phase. The size of the NiO-MgO phase in the resulting composite is reduced with the increase in MgO (the x value). The composite thus obtained is used to catalyze partial oxidation of methane, and the maximum methane conversion of ca. 93% is achieved when x = 0.2. A further rise in x value results in a monotonic decrease in the methane conversion. X-ray diffraction, electron microscopy, and chemosorption all confirm a decrease in both size and amount of the supported Ni-0 clusters with the increase in MgO dosage. The reduction in size promotes the dispersion of Ni-0 sites and gives rise to both high activity and strong coking resistance.