Diving into the interface-mediated Mars-van Krevelen (M−vK) characteristic of CuOx-supported CeO2 catalysts

The unique interface synergistic catalytic properties for metal oxide-supported catalysts have long been explored in several critical heterogeneous catalytic processes (e.g., CO oxidation reactions). However, interfacial synergistic catalysis is still a hitherto undescribed mechanism due to the lack of direct evidence at the atomic level. Thereinto, the CuO x -supported CeO 2 (CuO x /CeO 2 ) catalyst is a typical case. Herein, a combination study including representative theoretical calculations, in situ DRIFTS spectra and tailored molecular probe experiments supports a new carbonate-interface mediated Mars-van Krevelen (M−vK) mechanism for CO oxidation, i.e., CO molecules form carbonate intermediate species directly between spatial proximity (2.99 Å) double lattice oxygen sites with low oxygen vacancies formation energy (E form O v = 0.82 eV/0.83 eV) at the copper−ceria interface. The reaction energy barrier of this process is 0.32 eV, much lower than the 1.23 eV of the conventional M−vK mechanism. Besides, the spatial effect of double oxygen vacancies (O v ) generated by the depletion of intermediate carbonate species promotes the sustained and dynamic activation of O 2 , hence facilitating the efficient operation of the M−vK mechanism at low temperatures.