Revealing the catalytic ability of 5%Rh–5%Pt–5%Al2O3–85%CeO2 for CH4-based mixing fuel gases operating at 550 °C

Abstract

With the work temperature of solid oxide fuel cells (SOFCs) lower to 400–600 °C, the use of CH4-based fuel gas needs to be pre-reformed into synthesis gas (H2 and CO) to mitigate anode carbon deposition. Although lots of catalysts have been widely studied for methane conversion, the development of low temperatures (below 550 °C) catalyst for efficient methane reforming reactions remains a challenge. Here, we proposed a nanosize 5%Rh–5%Pt–5%Al2O3–85%CeO2 composite catalyst (RPAC-550), which demonstrates excellent reforming reactions for CH4-based mixing fuel gases operating at 550 °C. In this work, the reforming process of RPAC-550 catalyst for dry CH4, CH4/H2O and CH4/CO2/H2O atmospheres in different ratios and operating at 550 °C were systematically studied. Then the obtained reforming gases and carbon deposition were studied thoroughly to get the optimum ratio of mixed fuel gases for SOFCs. At last, the designed RPAC-550 catalyst achieves a CH4 conversion rate as high as 60% with water-methane ratio in 0.6. Herein, the ratio of H2 and CO as reforming gases can be controlled precisely by adjusting the intake amount of oxidant CO2 and H2O into CH4, which is beneficial for customizing fuel gases. In addition, the RPAC-550 catalyst exhibits remarkable catalytic stability and anti-coking ability under 600 h continue test. This work provides new insights for the rational design of efficient catalysts to reform methane-based fuel gas at 550 °C.