Abstract: Some novel biochar-supported Gd-Mn mullite oxides (GdMn₂O₅ and GdMn₂O₅/BC) were prepared by the hydrothermal method for the efficient catalytic oxidation of volatile organic compounds (VOCs) waste gas in synergy with ozone. The structure, morphology and catalytic potential of the supported catalysts were characterized and evaluated by means of SEM, TEM, XRD, XPS and N₂ adsorption-desorption. The effects of application conditions and supporter types on the catalytic performance of mullite for the oxidation and degradation of 2-octanol were investigated. The results show that the T₉₀ for the catalytic oxidation of 2-octanol by GdMn₂O₅ is 177℃, and it is completely degraded at 201℃, with a CO₂ conversion rate of approximately 80%. The biochar-supported mullite catalyst can reduce the activation energy of the oxidation reaction of 2-octanol with ozone and increase the number of active oxygen species and oxygen vacancies on the catalyst surface. The catalytic oxidation of 2-octanolunder the synergistic effect of the catalyst and ozone follows Mars-van Krevelen (MvK) mechanism.The consumption-supplementation cycle of oxygen vacancies, lattice oxygen and active oxygen species, as well as the electron transfer between Mn⁴⁺ and Mn³⁺ is the basis for the occurrence of the catalytic reaction.