Tuning the coordination environment of Cu in MnO2 catalysts: The critical role of lattice doping in promoting toluene oxidation

Precisely controlling active-site architecture is key for non-noble metal oxide catalysts in volatile organic compounds elimination. Herein, we demonstrate that lattice-doped Cu, rather than surface-loaded Cu, plays a decisive role in regulating the coordination environment and defect chemistry of MnO 2 , thereby fundamentally enhancing its toluene oxidation performance. Combined theoretical and experimental studies reveal that lattice-doped Cu creates a favorable coordination environment by significantly reducing oxygen vacancy formation energy and increasing electron density near the Fermi level. As a result, the Cu-Mn catalyst achieves 90 % toluene conversion at 218 °C, outperforming surface-loaded Cu/Mn (229 °C) and pristine MnO 2 (250 °C). The enhanced activity originates from the coupled increase of Mn 3 + species and oxygen vacancies, which synergistically improves reducibility and oxygen activation. In-situ DRIFTS further demonstrates that lattice-doped Cu facilitates aromatic ring opening and accelerates deep oxidation pathways. In addition, the Cu-Mn catalyst exhibits excellent hydrothermal stability under humid conditions, underscoring its practical potential. This work establishes a clear structure-activity-mechanism relationship and highlights lattice Cu doping as a general strategy for designing efficient non-noble metal oxide catalysts for VOC abatement.