Influence of potassium on the competition between methane and ethane in steam reforming over Pt supported on yttrium-stabilized zirconia

The effect of addition of potassium to Pt supported on yttrium-stabilized zirconia (PtYSZ) catalyst for steam reforming of methane, ethane and methane/ethane mixtures was explored. Addition of potassium has a positive effect on preferential steam reforming of methane in mixtures of methane and ethane over Pt/YSZ catalysts. The activity of potassium-modified catalysts increased with time-on-stream during steam reforming of mixtures of methane and ethane, while the ratio of reaction rates of methane and ethane remained constant. Most importantly, it was demonstrated that the presence of potassium prevents competition between methane and ethane during steam reforming. The reaction rate ratio in methane/ethane mixtures is changed from preferential ethane reforming on PtYSZ towards preferential methane conversion as a result of addition of potassium. This study shows that the steam reforming rates of methane and ethane are affected differently by the presence of potassium on supported Pt catalysts. As a result, competition effects in mixtures containing the two hydrocarbons diminished and improved methane conversion was possible. ▪