Effect of Oxygen Defects on the Catalytic Performance of VO_<i>x</i>/CeO₂ Catalysts for Oxidative Dehydrogenation of Methanol

Abstract

In this work, CeO₂ nanocubes with controlled particle size and dominating (100) facets are synthesized as supports for VO_<i>x</i> catalysts. Combined TEM, SEM, XRD, and Raman study reveals that the oxygen vacancy density of CeO₂ supports can be tuned by tailoring the particle sizes without altering the dominating facets, where smaller particle sizes result in larger oxygen vacancy densities. At the same vanadium coverage, the VO_<i>x</i> catalysts supported on small-sized CeO₂ supports with higher oxygen defect densities exhibit promoted redox property and lower activation energy for methoxyl group decomposition, as evidenced by H₂-TPR and methanol TPD study. These results further confirm that the presence of oxygen vacancies plays an important role in promoting the activity of VO_<i>x</i> species in methanol oxidation