Biphasic intergrowth effects of La2MnNiO6–MgO composite oxide for methane catalytic combustion

• Double perovskits La2MnNiO6 is a novel catalyst for methane combustion.
• La2MnNiO6–MgO composite oxide was prepared by biphasic intergrowth method.
• Effects of biphasic intergrowth are presented in the La2MnNiO6–MgO system.
• La2MnNiO6–MgO shows superior catalytic activity and stability for methane combustion.

Biphasic intergrowth La2MnNiO6–MgO composite oxide containing 30 wt% La2MnNiO6 was synthesized by ammonia aqueous (25 vol.%) co-precipitation method calcined at 1100 °C and investigated in the catalytic combustion of methane. Compared with the corresponding pure double perovskite-type oxide La2MnNiO6, the composite oxide La2MnNiO6–MgO exhibited much higher catalytic performance (T50 = 548 °C,T90 = 628 °C) and exceptional thermal stability. The excellent performance of La2MnNiO6–MgO was explained by various characterizations, such as XRD, ICP, H2-TPR, XPS, and TEM techniques. The catalytic activity of La2MnNiO6–MgO prepared by biphasic intergrowth method is superior to La2MnNiO6/MgO obtained by impregnation technique, mechanical mixing of La2MnNiO6 and MgO, and pure La2MnNiO6. The better performance of La2MnNiO6–MgO for methane catalytic combustion reaction is ascribed to a strong intergrowth interaction between La2MnNiO6 and MgO during the synthesis process. Therefore, the La2MnNiO6–MgO composite oxide can be deemed as an attractive candidate as a catalyst for the combustion of methane.

In this work, biphasic intergrowth La2MnNiO6–MgO composite oxide was successfully synthesized by novel method of biphasic intergrowth. The effects of biphasic intergrowth La2MnNiO6 and MgO were investigated in terms of the catalytic activity for methane combustion and physic-chemical properties. Experimental results showed that the introduction of sintering barrier MgO, not only efficiently hinder the sintering of perovskites particles but also simultaneously enhance their catalytic activities. Figures TEM image of La2MnNiO6–MgO; Temperature dependence of methane combustion over catalysts (a) La2MnNiO6–MgO prepared by biphasic intergrowth method, (b) pure La2MnNiO6, (c) mechanical mixing of La2MnNiO6 and MgO, (d) MgO and (e) blank.Figure optionsDownload high-quality image (224 K)Download as PowerPoint slide