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 (5.0 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.