Effect of the A-site cation on methane oxidation of perovskite-type (La1−xMx)CoO3 (M=Ca, Sr, and Ba)

► (La1−xMx)CoO3 (M=Ca, Sr, and Ba) was synthesized using the polymerizable complex method. ► The Co-O distance was constant regardless of the M ion or x. ► The Co-O-Co angle increased with an increase in the ionic radius of the M ion. ► CH4 oxidation started above 300 °C and finished at 700 °C. ► The catalytic activity increased with increases in the ionic radius of the M ion.