MOF-Derived Bimetallic Catalysts for Simultaneous Irradiation Degradation and Hydrogen Evolution: Synergistic Oxidation-Reduction Processes

Electron beam (EB) irradiation technology for organic pollutant degradation primarily exploits oxidizing radicals, while concurrently generated reducing radicals remain underutilized. These reducing species represent not only wasted energy but also impair degradation efficiency through radical neutralization. To overcome this limitation, we developed a synergistic catalyst designed to simultaneously harness both irradiation-driven oxidative and reductive free radicals. Mechanistic studies reveal that hafnium doping facilitates the valence conversion of iron from a purely divalent state (Fe²⁺) to a mixed Fe²⁺/Fe³⁺ state. This mixed-valence iron subsequently mediates free radical generation during water radiolysis through redox cycling between its divalent and trivalent states. Compared to EB irradiation alone, this catalytic system achieves 98% removal of the target pollutant (methyl orange), representing a 5-fold efficiency enhancement. Concurrently, hydrogen production efficiency increases nearly 5-fold. This work establishes a new paradigm for integrated pollutant degradation and energy harvesting.