Constructing Highly Active Metal Oxides for Toluene Degradation by Fenton Iron Mud Modulation

Fenton iron mud (IM) is a hazardous solid waste produced by Fenton oxidation technology after treating industrial wastewater. Thus, it is necessary and challenging to develop a recycling technology to back-convert dangerous materials into useful products. Herein, we develop a sustainable approach to prepare highly active metal oxides via a solid-state grinding method. IM, as an amorphous material, can disperse and interact well with these supported metal oxides, boosting toluene degradation significantly. Among these IM-based catalysts, the catalyst 8% MnO/IM-0.2VC exhibits the best performance (T₁₀₀ = 290 °C), originating from the oxide-support interaction and optimal balance between low-temperature reducibility and oxygen vacancy concentration. In addition, in situ diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) results expound that ring breakage is prone to occur on MnO, and oxygen vacancies are beneficial to adsorb oxygen and activate oxygen species to boost toluene oxidation following the Mars-van Krevelen mechanism. This work advances a complete industrial hazardous waste recycling route to develop extremely active catalysts.