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

Abstract

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 x /IM-0.2VC exhibits the best performance (T 100 = 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 x , 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.

Constructing Active Cu2+–O–Fe3+ Sites at the CuO–Fe3O4 Interface to Promote Activation of Surface Lattice Oxygen

“…In addition, similar trends of CO 2 yields to toluene conversion indicated that CFO−C-I and CFO−N-I possessed an excellent capacity to oxidize toluene and its intermediates (Figure S8). The catalytic activity of toluene oxidation over the previously reported TM oxides was summarized in Table S2, which shows that this surfactant-assisted catalyst surpassed the previously reported Cu−Fe bimetal oxides, such as CuFe 2 O 4 35 and Cu 3 Fe 1 O x -500, 36 and can be compared with the MnO xbased catalyst (8% MnO x /IM-0.2VC) 37 under similar reaction conditions. Subsequently, the reaction rates of toluene oxidation over the CuO−Fe 3 O 4 catalysts were calculated based on eq S4.…”

Efficient Photothermal Catalytic Oxidation Enabled by Three-Dimensional Nanochannel Substrates

“…Nevertheless, it is worth noting that the photothermal catalysis process tends to produce a higher quantity of benzoate species and yield more maleic anhydride species compared to thermo-catalysis. The ring-opening process of benzoate species is widely acknowledged as the pivotal rate-controlling step in toluene oxidation . The Pt/Co 3 O 4 /AAO catalyst plays a crucial role in enhancing the conversion of more intermediates into benzoate species, thereby optimizing the ring-opening process.…”

“…Limited by the low efficiency of photocatalysis and the high energy consumption of thermo-catalysis, a novel photothermal catalysis has been developed for VOC degradation. − It can harness full-spectrum solar energy and partially convert it into heat, which can greatly lower the light-off temperature required for VOC oxidation . However, most ongoing research in photothermal catalysis mainly focus on the physical and chemical properties of the catalysts, − overlooking the significance and mechanisms associated with the structure of monolithic catalysts in the photothermal catalytic reaction process.…”