Efficient and recyclable Ni–Ce–Mn–N modified ordered mesoporous carbon electrode during electrocatalytic ozonation process for the degradation of simulated high-salt phenol wastewater

In this study, an efficient and stable NiO/CeO2/MnO2-modified nitrogen-doped ordered mesoporous carbon (NOMC) particle electrode was developed, in which the metal oxides were mosaicked within the pore channels by one-pot skeleton hybridization, and the comodification of NiO/CeO2/MnO2/N was found to improve the electrocatalytic activity and stability of the particle electrode. The improved stability of the ordered mesoporous carbon towards pore collapse was applied to the degradation of simulated high-salt phenol wastewater by an electrocatalytic ozonation process using simple binder pelletization. The modified ordered mesoporous carbon shows a specific surface area of 269.7 m2 g-1 and a pore size of 3.17 nm, and SEM and TEM were used to show that the mesoporous structure is well maintained and the metal nanoparticles are well dispersed. The electrochemically active area of the Ni2%/Ce0.5%/Mn2.5%-NOMC particle electrode reaches 224.65 mF cm-2, which indicates that NiO improves the capacitance of the ordered mesoporous carbon and accelerates the electron transfer efficiency. Encouragingly, the phenol removal efficiency is found to reach up to 93.0% for 60 min over a wide range of pH values, with an initial phenol concentration of 150 mg L-1, low current (0.03 A) and fast reaction rate (0.0895 min-1), and the presence of CeO2 ameliorates the low activity of the particle electrode under acidic conditions. These results indicate that the presence of pyridine-N and β-MnO2 effectively mitigates carbon corrosion and improves electrode stability, as the accumulation of large amounts of ·OH at 20 min and the maintenance of a degradation efficiency of more than 90% after eight cycles provides a viable solution for the widespread practical application of ordered mesoporous carbon particle electrodes.