ZrO2-modified Ni/LaAl11O18 catalyst for CO methanation: Effects of catalyst structure on catalytic performance

We report Ni/LaHA@ZrO2 catalysts prepared by a facile modified successive adsorption and reaction method for CO methanation. N2 adsorption, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, H2 temperature-programmed reduction, H2 temperature-programmed desorption, X-ray photoelectron spectroscopy, thermogravimetric analysis, and inductively coupled plasma atomic emission spectrometry were used to characterize the samples. The results indicated that the ZrO2 nanoparticles were distributed over the surface of the Ni/LaHA@ZrO2 catalyst and even partially covered some Ni particles, resulting in the coating exerting a confinement effect. The excess ZrO2 had an adverse effect on the enhancement of CO conversion because of the coverage of the surface Ni particles; however, the Ni/LaHA@ZrO2 catalyst displayed much higher CH4 selectivity than Ni/LaHA because of the activation of the byproduct CO2 molecules by ZrO2 species. Therefore, even though 20Ni/LaHA@ZrO2-5 exhibited similar CO conversion as 20Ni/LaHA, the use of the former resulted in a higher CH4 yield than the use of the latter. A 107-h-lifetime test revealed that the Ni/LaHA@ZrO2 catalyst was highly stable with superior anti-sintering and anti-coking properties because of its coating structure and the promoter effect of ZrO2. Graphical abstract
Source: Chinese Journal of Catalysis - Category: Chemistry Source Type: research