Coupling Covalent Organic Frameworks and Carbon Nanotube Membranes to Design Easily Reusable Photocatalysts for Dye Degradation

Covalent organic frameworks (COFs) have been used as photocatalysts, but recovering COF particulates from aquatic environments is tedious and labor-consuming. In order to maximize the photocatalytic performance and simplify the degradation processes, carbon nanotube (CNT) membranes with excellent electron transfer capacity and photothermal effects are used as substrates to fabricate COF/CNT membranes. The uniform COF layer enhances the mechanical property and hydrophilicity of the CNT membranes. Meanwhile, by utilizing the large surface area and photothermal effect of the CNT membranes, the photocatalytic activity of COF-based composite membranes can be improved to match that of pure COF particulates. Due to the positive interaction between COFs and CNT membranes, the composite membranes exhibit superior degradation capacity toward mordant black 17 (MB17) with strong handleability. The total degradation capacity of COF/CNT membranes can reach 708.2 mg/g, and the composite membranes can be reused seven times with only 10.6% efficiency loss in degradation capacity.