Different Active Sites of LaCoO3 and LaMnO3 for CH4 Oxidation by Regulation of Precursor’s Ion Concentration

(Pages 28-39)
Saifei Wang1, Yiyuan Zhang1, Peiqi Chu1, Jie Liu1, Man Wang1, Peng Zhang2 and Erhong Duan1

1School of Environmental Science and Engineering, Hebei University of Science and Technology, 26th Yuxiang Street, Shijiazhuang Hebei, 050018, and 2Hebei NCPC Environment Protection & Research Co., Ltd, Shijiazhuang, Hebei, 050015, PR China



Abstract: Pure LaCoO3 and LaMnO3 were synthesized under different ion concentrations of precursors and the difference of active sites for CH4 oxidation between them was found. As the ion concentration of precursors increased, the two kind of perovskite crystals grew larger along with agglomerate. Meanwhile, LaCoO3 and LaMnO3 prepared by high ion concentrations of precursors enriched more surface Co3+ or Mn4+. The catalytic activity of the catalysts was tested in the oxidation reaction of methane under fuel-lean condition, results showed that LC-1.0 and LM-2.0 had the optimal activity and the light-off temperatures were 492°C and 486°C, respectively. Combining the physical and chemical characterization, the LaCoO3 and LaMnO3 possess different active sites for the methane catalytic reaction, and the conclusion was further verified by the DFT simulation. For LaCoO3, the surface lattice oxygen is the main active site, while for LaMnO3, the reaction is facilitated by the high-valent manganese.

Keywords: Perovskite; Methane oxidation; Active sites; DFT simulation.