Nanoconfinement in ordered mesopores materials for catalytic wastewater purification

Abstract

Catalytic advanced oxidation processes (AOPs) have been challenged by low utilization efficiency of the reactive oxygen species, non-selective oxidation, hindered mass transfer, and reduced stability and activity of catalysts. Catalysis under nanoconfinement shows distinctive physicochemical properties and phase behavior that address the technical bottlenecks of AOPs; however, the confinement efficiency is highly dependent on substrate pore size. In this regard, ordered mesoporous materials (OMMs) and nanoreactors are specially promising to provide uniformly nanoconfined channels and microenvironment, effectively boosting catalytic oxidation performances during the wastewater purification. In this critical review, we first systematically elucidate the fundamentals of nanoconfinement in AOPs, focusing on its effects on chemical reactivity of reactants and intermediates, the stability and activity of catalysts, and the spatial nanoconfinement among different dimensional structures. Subsequently, the synthesis of OMMs with on-demand porous structure to facilitate nanoconfined reactions are reviewed. Afterwards, we discuss the applications of nanoconfined OMMs in catalytic wastewater purification from three aspects: redox agent-driven AOPs, electricity-driven AOPs, and light-driven AOPs. In conclusion, we summarize the fundamentals and application challenges of OMMs and their nanoconfined features in AOPs for wastewater purification, proposing strategies to drive advancements in this field.