Effects of preparation methods and Cu/Co ratio on the catalytic performance of Cu–Co catalysts for ultra-low concentration methane combustion

The efficient removal of ultra-low concentration methane from sources like coal mine ventilation air is crucial for mitigating greenhouse gas emissions. This study systematically investigates the effects of synthesis methods (impregnation, combustion, sol-gel, and co-precipitation) and Cu/Co ratios on the catalytic performance of Cu-Co/CeO 2 catalysts for ultra-low concentration methane combustion. Characterization results demonstrate the structural advantages of the optimal catalyst. XRD patterns confirm the successful formation of a CuCo 2 O 4 spinel phase. SEM images show a uniform morphology with minimal agglomeration. XPS analysis further reveals the coexistence of Cu 2+ /Cu + and Co 3+ /Co 2+ redox couples accompanied by abundant adsorbed oxygen species. Experiments demonstrate that the 1Cu-4Co/CeO 2 catalyst prepared by co-precipitation exhibits optimal low-temperature activity, with T 10 and T 90 values of 330 °C and 566 °C, respectively. Stability evaluations over 20 h at 500 °C show minimal activity decay, with the catalyst retaining 94.2% of its initial conversion. The superior performance is attributed to the synergistic redox interaction between Cu and Co, optimized surface oxygen mobility, and robust structural stability. This work provides an effective strategy for designing non-noble metal catalysts for ultra-low concentration methane purification.