Demonstrating Sustainable Nitro‐Aromatic Reduction at Near‐Saturation Concentration and Ambient Conditions Using Photothermally Confined Fe–Ru Bimetallic Nanoparticle

Abstract Management of high, near‐saturation concentrations of organic contaminants in aqueous effluent streams by converting them to value‐added products is highly desirable and yet challenging. Rapid and direct conversion of p ‐nitrophenol (PNP) to p ‐aminophenol (PAP) under ambient conditions at industrially relevant concentrations (115 mM) faces significant challenges such as catalytic poisoning from undesirable quinone products and sluggish kinetics due to mass‐transfer limitations leading to unsustainable energy requirements. We demonstrate a photothermal catalyst consisting of plasmonic Fe–Ru nanoparticles confined within non‐plasmonic nanostructured carbons (Fe–Ru@C10) that delivers quantitative and rapid conversion of PNP at the highest‐possible concentration (115 mM) to PAP, with excellent turnover frequency (7642 h −1 ) in ambient conditions, to achieve strong sustainability metrics (E‐factor: 1.3 × 10 −5 , PMI →1, carbon efficiency→100%, eco‐scale ∼85%). Photothermal synergism between Fe–Ru sheathed by mesoporous nanocarbon in Fe–Ru@C10 enables facile diffusional access of reactants and products to maintain fast pseudo‐first‐order kinetics (0.26 min −1 ) while simultaneously preventing catalyst deactivation by aggregation and poisoning. This robust and recyclable catalyst outperforms conventional catalysts, having exposed and accessible active sites while utilizing the lowest equivalent of reductant ([NaBH 4 ]/[PNP]∼ 24.5), thereby carrying potential impact for sustainable and energy‐efficient management of environmental contaminants.