Light‐Induced Structural Reorganization of Fe Centers Unlocks High Efficiency of Visible‐Light Photo‐Fenton Water Cleaning Catalyst

Fenton‐like advanced oxidation processes (AOPs) are among the most industrially relevant technologies for removing organic pollutants from water. In this work, we evaluate mono‐ and bimetallic (Cu and/or Fe) catalysts, supported on porous silica with interparticle mesoporosity, in visible light driven photo‐Fenton like systems for the degradation of the model contaminant bisphenol A (BPA). Introducing light significantly enhances the catalytic activity of the bimetallic CuFe system. The mechanism proceeds in two interconnected stages. First, illumination promotes a photo‐Fenton like Cu 2+ /Cu + redox cycle. Subsequently, Cu + species generated at the catalyst surface facilitate Fe 2+ regeneration via a thermodynamically favorable electron‐transfer pathway enabled by Cu–O–Fe bridges, thereby sustaining the Fe 3+ /Fe 2+ Fenton cycle at neutral pH. In situ X‐ray absorption spectroscopy further reveals that light induces a structural reorganization of the Fe coordination environment, increasing the proportion of tetrahedrally coordinated Fe 3+ , a geometry known to be highly active in Fenton reactions. The most effective CuFe catalyst achieves complete BPA removal in 90 min and retains stable performance over four consecutive cycles. Overall, our findings demonstrate that visible light plays a dual mechanistic role: it drives electronic processes (e.g., charge carrier generation and redox cycling) while simultaneously triggering a coordination rearrangement of Fe centers, producing light‐activated catalytic state. The novelty lies in establishing a structure–property–activity relationship supported by in situ structural evidence and introducing light‐activated coordination dynamics as a new mechanistic and design principle for heterogeneous AOP catalysts, beyond that of simply combining Cu and Fe or use of visible light alone.