Improved Catalytic Activity and Stability of Ba Substituted SrTiO<sub>3</sub> Perovskite for Oxidative Coupling of Methane
Yue Wang, Yang Xiao, Chenxiao Hou, Fumin Yin, Guowei Wang, Xiaolin Zhu, Guiyuan Jiang, Chunyi Li
Abstract
Abstract Perovskite oxides are widely used as the catalyst for oxidative coupling of methane (OCM). The partial substitution of A or B sites in ABO 3 perovskites with heteroatoms was effective in improving the catalytic performance, but the promoting mechanism has not been thoroughly studied. In this work, the partial substitution of Sr with Ba in SrTiO 3 perovskite was demonstrated to improve both the OCM reaction activity and stability. Compared with SrTiO 3 and BaTiO 3 , the crystal size of Ba 0.5 Sr 0.5 TiO 3 was greatly reduced (∼55 nm), the amount of surface chemisorbed oxygen species acting as the alkaline active centers for OCM was increased, and the electrophilic lattice oxygens with higher electronegativity rapidly replenishing the surface alkaline active sites were obtained. Thereby, a higher C 2 yield (∼18 %) and C 2 H 4 /C 2 H 6 ratio (∼1.7) were simultaneously achieved. Furthermore, the enhanced reaction stability was attributed to the better thermal resistance of nano‐sized Ba 0.5 Sr 0.5 TiO 3 perovskite.