Enhanced Electrocatalytic Degradation of Phenol by Mn-MIL-100-Derived Carbon Materials

To achieve high electrooxidation efficiency for phenol, this study explored the fabrication of Mn-MIL-100 catalysts at various calcination temperatures, loaded onto a carbon paper (CP) anode. The materials were characterized using scanning electron micros-copy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and X-ray diffraction. Their electrocatalytic activities under various calcination temperatures were evaluated through cyclic voltammetry (CV) tests, while the effect of pH in the Mn-MOF modified CP electrodes on phenol degradation performance was investigated using the potentiostatic discharge method. Mn-MOF@CP calcined at 400 °C and 500 °C (denoted as Mn400@CP and Mn500@CP, respectively) exhibited significantly enhanced cyclic voltammetry current responses in phenol solution, attributed to an increase in oxygen vacancy concentration. A phenol degradation efficiency of 96.00 ± 1.53% was achieved by Mn400@CP within 16 h, while it was only 60.12 ± 2.03% for Mn500@CP and 8.01 ± 2.00% for the blank CP at pH 4. Additionally, Mn400@CP consistently demonstrated superior phenol degradation efficiency over Mn500@CP across various pH values. The outstanding electrocatalytic activity of Mn400@CP for phenol oxidation could be attributed to its lower charge transfer resistance. A radical-mediated oxidation pathway was proposed for the Mn400@CP electrocatalytic system, elucidating its phenol degradation mechanism. These findings highlighted the potential of Mn-MOF-derived carbon-based materials for the degradation of organic contaminants.