In-Situ Synthesis of 3D ZIF-8 on 2D MXene Nanosheets for Efficient Photocatalytic Degradation of Methylene Blue (MB)

Abstract

Organic dyes such as methylene blue (MB), commonly discharged from the textile and paper industries, pose a serious hazard to aquatic ecosystems and human beings. Developing efficient strategies for dye degradation via photocatalytic processes is, therefore, of urgent importance. Metal–organic frameworks (MOFs) have emerged as promising photocatalysts owing to their high surface areas, tunable porosity, and structural diversity. However, the large band gap of pristine MOFs (typically >4.9 eV) often results in poor visible-light absorption and high charge recombination, limiting their practical applicability. Here, we report the in situ growth of three-dimensional zeolitic imidazolate framework-8 (ZIF-8) on two-dimensional Ti3C2 MXene nanosheets (ZIF-8@Ti3C2) via a facile precipitation strategy. The resulting 3D/2D hybrid architecture enhances light absorption, as confirmed by diffuse reflectance spectroscopy, and significantly narrows the band gap to 2.1 eV, substantially lower than that of pristine ZIF-8 (4.7 eV). Under visible light irradiation, the ZIF-8@Ti3C2 MXene heterostructure achieves a methylene blue degradation efficiency of 95% within 120 minutes, outperforming its components. This work presents a robust platform for engineering MOF-based heterostructures, offering a promising avenue toward sustainable photocatalytic water purification.