Abstract: Monolithic catalysts have been widely investigated for CO₂ methanation due to their fast mass and heat transfer rate, but the effect of the interaction between the catalyst layer and the monolithic support has been little studied. In this work, Ni/Al₂O₃/SiC monolithic catalysts, Ni/Al₂O₃ powder catalysts and Ni/Al₂O₃/SiC-M catalysts were prepared to explore the effect of Si-Al interaction between the catalyst layer and SiC ceramic for CO₂ methanation performance. Ni/Al₂O₃/SiC exhibited a CO₂ conversion of 53% and a CH₄ specific reaction rate of 0.05 mmol·g^-1·s^-1 under conditions of 0.1 MPa, 400 °C, and a WHSV of 60000 ml·g^-1·h^-1. The CO₂ conversion raised by 0.15-fold and the CH₄ specific reaction rate raised by 0.25-fold compared to Ni/Al₂O₃ with the same catalyst content. SEM, XRD, Raman, and other characterization results revealed that the formation of Si-Al interaction between the catalyst layer and SiC ceramic could weaken the interaction between Ni and Al₂O₃, thereby improving the catalytic activity of Ni/Al₂O₃/SiC catalyst. However, the Si-Al interaction was further strengthened during the high-temperature reaction process, which significantly weakened the interaction between Ni and Al₂O₃, thereby leading to a decline in the catalytic performance of Ni/Al₂O₃/SiC catalyst during an 80-h stability test. This study provides valuable insights for future research and development of monolithic catalysts.

Key words: Carbon dioxide, Hydrogenation, Monolith, Ni/Al₂O₃/SiC monolithic catalyst, Si-Al interaction

摘要： Monolithic catalysts have been widely investigated for CO₂ methanation due to their fast mass and heat transfer rate, but the effect of the interaction between the catalyst layer and the monolithic support has been little studied. In this work, Ni/Al₂O₃/SiC monolithic catalysts, Ni/Al₂O₃ powder catalysts and Ni/Al₂O₃/SiC-M catalysts were prepared to explore the effect of Si-Al interaction between the catalyst layer and SiC ceramic for CO₂ methanation performance. Ni/Al₂O₃/SiC exhibited a CO₂ conversion of 53% and a CH₄ specific reaction rate of 0.05 mmol·g^-1·s^-1 under conditions of 0.1 MPa, 400 °C, and a WHSV of 60000 ml·g^-1·h^-1. The CO₂ conversion raised by 0.15-fold and the CH₄ specific reaction rate raised by 0.25-fold compared to Ni/Al₂O₃ with the same catalyst content. SEM, XRD, Raman, and other characterization results revealed that the formation of Si-Al interaction between the catalyst layer and SiC ceramic could weaken the interaction between Ni and Al₂O₃, thereby improving the catalytic activity of Ni/Al₂O₃/SiC catalyst. However, the Si-Al interaction was further strengthened during the high-temperature reaction process, which significantly weakened the interaction between Ni and Al₂O₃, thereby leading to a decline in the catalytic performance of Ni/Al₂O₃/SiC catalyst during an 80-h stability test. This study provides valuable insights for future research and development of monolithic catalysts.

关键词: Carbon dioxide, Hydrogenation, Monolith, Ni/Al₂O₃/SiC monolithic catalyst, Si-Al interaction