Highly efficient and stable Ni/CeO2-SiO2 catalyst for dry reforming of methane: Effect of interfacial structure of Ni/CeO2 on SiO2

摘要

Manipulating interfacial structure and interaction between metal and supports is important for many heterogenous catalysts with the aim at achieving high and stable activity and selectivity. In this work, two kinds of Ni/CeO2-SiO2 catalysts are fabricated and designed, including CeO2 close contact with Ni nanoparticles (Ni/CeO2-SiO2-P) or CeO2 away from Ni nanoparticles (Ni/CeO2-SiO2-C) for dry reforming of methane. Ni/CeO2-SiO2-P exhibits superior low-temperature activity and H-2/CO ratio compared with Ni/CeO2-SiO2-C. CO2 and CH4 conversions on the former (87.3% and 78.5%) are higher than those of the later (80.5% and 67.8%) at 700 degrees C. Meanwhile, Ni/CeO2-SiO2-P is stable in the long-term study whereas Ni/CeO2-SiO2-C presents poor stability and the activity dramatically decreases in 10 h. The improved performance and stability on Ni/CeO2-SiO2-P originates from more reactive oxygen species and more accessible sites for the formate species on the metal support interface. The reaction order and activation energy of both catalysts are also calculated in the kinetic studies. This work opens up new possibilities for exploring the effect of metal support on designing highly efficient heterogeneous catalysts.