In this work, Co was selected to modify the structure of MnO₂, which forced the catalyst to transform from α-MnO₂ to spinel phase CoMn₂O₄. During this process, the metal–oxygen bonds were significantly weakened, inducing the massive generation of oxygen defects. As a result, the redox property and ability to adsorb and activate gaseous oxygen of Co modified catalysts was significantly enhanced, endowing the Co doped catalysts with strongly improved catalytic performance.

Manganese oxides are very important and conventional catalysts that have demonstrated appreciable catalytic activity for the oxidation of volatile organic compounds (VOCs). Nevertheless, pure manganese oxides suffer from poor activity especially at low temperatures, making it difficult to meet industrial applications. In this work, Co species were successfully doped into the lattice of MnO₂ aiming at constructing defects to boost its catalytic performance for VOCs oxidation. In combination with the results of systematic characterizations, we found that Co doping forced the catalyst to transform from α-MnO₂ to spinel phase (Co,Mn)(Co,Mn)₂O₄. During this process, the metal–oxygen bonds are significantly weakened, which induces the massive generation of oxygen defects, endowing the Co modified catalysts with enhanced redox property and improved ability to adsorb and activate gaseous oxygen. As a result, Co doped catalysts show much better catalytic activity compared with pristine α-MnO₂, among which Mn₁₀Co₁₀ exhibits the best performance showing a decrease of 41°C and 51°C in T ₅₀ and T ₉₀ compared with the raw sample, respectively. Furthermore, Mn₁₀Co₁₀ demonstrates excellent stability, water resistance, and reusability, illustrating a great potential for industrial applications. Moreover, path of toluene decomposition over Co₁₀Mn₁₀ was revealed by in situ DRIFTS experiment, which complies with the sequence of toluene → benzyl alcohol → benzaldehyde → benzoate → maleic anhydride → CO₂ and H₂O.