Activation of Co-O - O bond in {110} facet exposed Co3O4 3 O 4 by La doping for the boost of toluene catalytic oxidation

A strategy to improve the toluene oxidation properties through La doping and citric acid modification is proposed. In particular, when the ratio of citric acid to metal is 2 (CCoLa-2), due to the differing nucleation rates of the La and Co precursors, the {1 10} crystalline facets in Co3O4 3 O 4 are exposed, which promotes the formation of more electron-deficient Co3+ 3+ ions along with an abundance of surface lattice oxygen, which facilitates the catalysis of toluene. Meanwhile, the interfacial effect produces by the doping of La induces the presence of La3+-O-Co3+/La3+-square-Co2+ 3+ -O-Co 3+ /La 3+ -square-Co 2+ structure in CCoLa-2, which reduces the electron concentration around the surface lattice oxygen and weakens the Co-O - O bond intensity, thus enhancing the activity of the surface lattice oxygen. Finally, CCoLa-2 possesses outstanding oxygen replenishment ability to rapidly degrade the tough intermediate species benzyl alcohol and benzoic acid, thus accelerating the catalytic cycle.