Coking occurs easily and would significantly degrade the electrochemical performance for hydrocarbon-fueled solid oxide fuel cells (SOFCs). Here, we report an integrated device combining a SOFC and a stainless steel tubing as catalyst for hydrocarbon pyrolysis in the upstream of the fuel cell. Considerable carbon nanotubes (CNTs) are grown around the outside of the stainless steel tubing when dimethyl ether (DME) is fed to the device, which dramatically reduces the C:O ratio in the fuel reaching the cell anode. Correspondingly, the carbon-removal reforming significantly prolongs the performance stability of the fuel cell compared to that directly fueled by DME. The present results suggest that hydrocarbons can be utilized more efficiently and economically by combining a SOFC and a fix-bed reactor containing catalysts for CNTs formation, accompanying with the co-generation of electric power and CNTs.