Dynamic Mn-VO Associates Boosted Molecular Oxygen Activation for Benzene Combustion on Mn-Doped Mesocrystalline CeO2.

Highly efficient molecular oxygen activation over transition metal oxides toward catalytic abatement of aromatic volatile organic compounds (AVOCs) is possible yet challenging due to the easily deactivated surface oxygen vacancy (VO). Herein, dynamic Mn-VO associates were crafted onto the Mn-incorporated CeO2 mesocrystal (Mn/meso-CeO2) surface with Mn substituting a Ce atom through an easy-to-handle precipitation strategy. Experiments and theoretical calculation demonstrated that the asymmetric surface Mn-O-Ce configuration induced electron delivery from the low-valent Mn to adjacent Ce, destabilizing the circumambient O atoms and facilitating the formation of dynamic Mn-VO associates. Compared to pristine meso-CeO2, the Mn/meso-CeO2 with dynamic Mn-VO associates could efficiently activate O2 into a superoxide radical and a peroxanion (O2•- and O22-) at higher reaction temperature (over 200 °C). Meanwhile, the O atom adjacent to Mn featuring substantially elevated Lewis acidity promoted the adsorption and activation of benzene. Consequently, the Mn/meso-CeO2 catalyst exhibited a superior catalytic oxidation reactivity (T90 = 215 °C) toward C6H6 combustion via a Langmuir-Hinshelwood mechanism. This work underlines the importance of rational design and regulation of catalytic sites over metal oxide surfaces for robust O2 activation and durable refractory AVOC combustion.