CeMnOX catalysts for enhanced ozonation of phenol: Performance evaluation and mechanism investigation

In order to enhance the catalytic activity and stability of transition metal catalysts in heterogeneous ozonation and effectively treat phenol-containing wastewater, we synthesized a cerium-manganese composite catalyst (CeMnO_X) using hydrothermal and calcination methods. The results show that Mn atoms doped into the CeO₂ lattice form CeMnO_X solid solution, which possesses abundant surface defects. The large specific surface area and pore volume of the catalyst favor the exposure of active sites. The CeMnO_X catalyst contains rich redox pairs and a high amount of chemisorbed oxygen, with numerous oxygen vacancies serving as reactive sites, thereby improving catalytic performance. Degradation experiments demonstrated that the CeMnO_X catalyst achieved nearly 100 % COD removal within 30 min during catalytic ozonation of phenol, with a significantly higher catalytic efficiency than pure CeO₂ or MnO_X. Among them, Ce_0.3Mn_0.7O_X exhibited the best performance due to the presence of both the CeMnO_X solid solution and MnO_X phases. The combined effect of oxygen vacancies and the synergistic interaction between Ce and Mn is critical to the exceptional catalytic activity of the CeMnO_X catalyst.