A facile synthesis of CuCe and CuCeFe mixed-oxide catalysts by solution combustion method for catalytic methane combustion

Abstract

In this research, the solution combustion method was used to synthesize non-noble catalysts including copper-cerium (CuCe) and copper-cerium-iron (CuCeFe) mixed-oxides for catalytic combustion of methane. The effects of Cu contents (5, 10 and 15 wt%) and Fe addition were investigated. The synthesized catalysts were characterized by XRD, N2-physisorption, and H2-TPR. The results showed that increasing Cu content exceeds 10 wt% for a series of CuCe catalyst, leading to a collapse textural structure and formation of larger CuO phase. It resulted in the substantial drop of the catalytic activity for methane combustion. Furthermore, incorporation of Fe into Cu-Ce mixed oxides causes the formation of Fe2O3 and Ce-Fe-O solid solution, stabilizing the textural properties, enhancing the oxygen vacancies and oxygen mobility. The superior catalyst was 15CuCeFe because it revealed the highest methane conversion at 500 °C and relatively high conversion at a lower temperature. It can be seen that solution combustion is a facile method to prepare the mixed-oxide catalysts and incorporating the metal promoters. The Cu, Ce and Fe metals play a significant role in catalytic methane combustion not only enhancing reactants (methane and oxygen) activation but also improving the physical properties.