Defect‐Engineered MOF/COF S‐Scheme Heterojunction With Dual‐Channel Charge Transport for Ultraefficient Solar‐Powered Heavy Metal Remediation

Rapid recombination of photogenerated carriers severely limits the photocatalytic performance of conventional semiconductor photocatalysts, while conventional heterojunctions generally suffer from inefficient charge separation and sluggish interfacial kinetics due to poor lattice matching and unidirectional recombination. Herein, we break through these limitations by constructing an oxygen vacancies (OVs)-mediated S-scheme via covalent bridging between a metal-organic framework (MOF) and a covalent organic framework (COF), coupled with vacuum-induced OVs engineering. This novel architecture not only preserves the strong redox potentials of the constituent materials but also introduces dual-channel charge transport pathways significantly enhancing carrier separation. Femtosecond transient absorption spectroscopy (fs-TAS) reveals that the OVs-induced trap states extend the carrier lifetime to 278 ps-2.5 times longer than the parent materials. The optimized catalyst achieves exceptional removal efficiencies for multiple heavy metal ions (Cu⁺, ReO₄ ^-, MoO₄ ² ^-, MnO₄ ^-, Cr₂O₇ ² ^-, and UO₂ ²⁺), with UO₂ ²⁺ removal rates 8.8 and 17.1 times higher than those of the pristine MOF and COF, respectively. This work presents a universal "defect-mediated dual transport" strategy, offering new insights into solar-driven environmental purification and energy conversion.