Effect of ZrO2 promoter on the catalytic activity for CO methanation and adsorption performance of the Ni/SiO2 catalyst

The catalytic activities for CO methanation and adsorption performances of the Ni/SiO2 and Ni/ZrO2-SiO2 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/ZrO2-SiO2 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/SiO2 catalyst under the same reaction condition, and CO was not completely converted until 270°C, which suggested that the catalytic activity of the Ni/ZrO2-SiO2 catalyst increased with the addition of ZrO2 promoter. Meanwhile, the addition of ZrO2 promoter enhanced the CO adsorption capacity of the Ni/ZrO2-SiO2 catalyst. In the presence of H2, a large number of bridged carbonyl hydrides were formed over the Ni/ZrO2-SiO2 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.