The greenhouse effect of methane is 25 times that of the same volume of carbon dioxide. The low-concentration methane (especially the ventilation air methane) emitted from coal mining is huge and discharged into the atmosphere, which wastes energy and intensifies the earth greenhouse effect. The catalytic co-combustion of the low-concentration methane in the mine exhaust air and the coal in the boiler under high efficiency catalyst can be achieved, which can not only realize the complete combustion of the low-concentration methane in the mine exhaust air, but also reduce the greenhouse effect caused by methane emission. Furthermore, it promotes the full combustion of coal in the boiler, which increases the heating value of coal-fired boiler. A Co3O4/SiO2-x catalyst with con-trollable particle size of Co3O4 and supported on silicon dioxide was prepared by using piperazine and pyromellitic acid hydrate as linker at different calcination temperatures. A series of characterization methods such as XRD, BET, H2-TPR