This work reports a procedure for increasing VOC removal from flue gas using binary oxides (Ce-Mn) supported on fly ash by facile mechanochemical synthetic method in the presence of a solid organic acid ligand (OAL). The presence of OAL during the synthesis process helped produce larger and more accessible particle surface areas, by generating an abundance of micro-/meso porous structures. Meanwhile, the Ce-Mn interaction was enhanced in the catalyst produced (Ce-Mn-OFA) by the presence of OAL during the milling process, yielding a higher ratio of Mn³⁺/Mn⁴⁺ and Ce³⁺/Ce⁴⁺, more lattice defects and surface oxygen vacancies, and greater lattice oxygen mobility. The resulting changes in the fly ash properties substantially improved the oxidation and adsorption activity of Ce-Mn-OFA thus enhancing the catalyst’s potential for VOC removal. The Ce-Mn-OFA catalyst showed the highest catalytic activity for benzene, toluene, m-xylene, and ethylene, which reached 90% conversion at 283 °C, 237 °C, 216 °C, and 264 °C, respectively. More importantly, the presence of the OAL increased the reactive oxygen species and acid sites on the surface of Ce-Mn-OFA, thus weakening the inhibiting effect of NO, NH₃, H₂O, and SO₂ on the VOCs oxidation process. Furthermore, when Ce-Mn-OFA was applied using a special injection system to a large-scale pilot unit, the total concentration of 12 VOCs in the flue gas was reduced from 1347.3 μg/m³ to 131.2 μg/m³. The main contributions of the present work can be summarized as follows: 1) Providing a facile and environmentally friendly new process for the preparation of a heterogeneous catalyst; 2) Revealing the mechanism by which OAL enhances the activity of Ce-Mn in a binary metal oxide catalyst; 3) Evaluating the performance of Ce-Mn-OFA in a real flue gas, which provides feasibility support for its industrial application, such as in coal-fired power plants.