Combined Experimental and Density Functional Theory Study on the Mechanism of Catalytic Oxidation of Methanol over CeO 2 with Various Exposed Crystal Facets

Catalytic oxidation is an effective method for removing methanol emitted from industrial production and the combustion of methanol as a clean energy source. In this work, the mechanism of the catalytic oxidation of methanol on CeO 2 with various morphologies (nanorods, nanoparticles, and nanocubes) and hence different exposed crystal facets was studied by various designed experiments and density functional theory (DFT) calculation. It was demonstrated that the oxidation of methanol on the CeO 2 surface follows the reaction pathway of CH 3 OH → −CH 3 O → HCHO → HCOOH → CO + H 2 O → CO 2 . The activation of O 2 was the rate-determining step of the entire catalytic oxidation reaction. CeO 2 nanorod-exposed (111) and (100) facets exhibited superior catalytic activity due to their rich oxygen vacancies and surface O ads compared with the CeO 2 nanoparticle mainly exposed (111) facet and the CeO 2 nanocube mainly exposed (100) facet. When considering the specific surface area, nanocubes had the highest specific activity as the (100) facet has a stronger ability for O 2 activation than the (111) facet. These findings clarified the reaction pathway and rate-determining step of methanol oxidation on CeO 2 -based catalysts and provided valuable insights into the development of high-performance catalysts for oxygen-containing VOC oxidation.