Effect of ZrO 2 promoter on the catalytic activity for CO methanation and adsorption performance of the Ni/SiO 2 catalyst

Abstract

The catalytic activities for CO methanation and adsorption performances of the Ni/SiO 2 and Ni/ZrO 2-SiO 2 catalysts were investigated by a continuous flowing microreactor apparatus and in-situ diffuse reflectance Fourier transform infrared spectroscopy. The results showed that CO was completely converted at 200°C over the Ni/ZrO 2-SiO 2 catalyst under the reaction condition of 1% of CO, GHSV of 5000 h −1, and the atmospheric pressure. However, the CO conversion was only 35% over the Ni/SiO 2 catalyst under the same reaction condition, and CO was not completely converted until 270°C, which suggested that the catalytic activity of the Ni/ZrO 2-SiO 2 catalyst increased with the addition of ZrO 2 promoter. Meanwhile, the addition of ZrO 2 promoter enhanced the CO adsorption capacity of the Ni/ZrO 2-SiO 2 catalyst. In the presence of H 2, a large number of bridged carbonyl hydrides were formed over the Ni/ZrO 2-SiO 2 catalyst at lower temperatures, resulting in high catalytic activity for CO methanation. In CO methanation, the breaking of C—O bond over catalysts was by multihydrogen carbonyl hydride rather than by direct breaking.