Simple and Controllable Synthesis of High-Quality MnTiO₃ Nanodiscs and Their Application as A Highly Efficient Catalyst for H₂O₂-Mediated Oxidative Degradation

Herein, we reported a simple synthesis of monodisperse, uniform, and highly crystalline MnTiO3 nanodiscs and their application as a new promising catalyst for H2O2-mediated oxidative degradation. Unlike previously reported method that required use of preprepared titanate nanowires as precursor, this synthesis of well-defined MnTiO3 nanodiscs was implemented through a one-pot homogeneous reaction process under hydrothermal conditions. The growth of MnTiO3 nanodiscs was revealed to follow the nucleation–dissolution–recrystallization mechanism, and the (001) crystal facet was preferentially exposed since it was the densest and most thermodynamically stable. Two-dimensional flat plane of the MnTiO3 nanodiscs helped minimize the diffusion pathway of guest molecules, thus allowing a fast mass transport. Moreover, the Mn(II)-rich structure and distinct crystallinity endowed MnTiO3 nanodiscs with high activity and stability. In the presence of H2O2, MnTiO3 nanodiscs exhibited a high efficiency in catalytic decomposition of a series of organic pollutants with an excellent recycling durability. About 98.6% of methylene blue was catalytically decomposed within 20 min at 30 °C. When the reaction temperature increased to 40 °C, only 8 min was required. Comparative investigation further confirmed the superior catalytic performance of MnTiO3 nanodiscs, with about 2 times higher removal efficiency than reported under similar conditions.