In situ single iron atom doping on Bi₂WO₆ monolayers triggers efficient photo-fenton reaction

Developing an efficient photocatalytic system for hydrogen peroxide (H₂O₂) activation in Fenton-like processes holds significant promise for advancing water purification technologies. However, challenges such as high carrier recombination rates, limited active sites, and suboptimal H₂O₂ activation efficiency impede optimal performance. Here we show that single-iron-atom dispersed Bi₂WO₆ monolayers (SIAD-BWOM), designed through a facile hydrothermal approach, can offer abundant active sites for H₂O₂ activation. The SIAD-BWOM catalyst demonstrates superior photo-Fenton degradation capabilities, particularly for the persistent pesticide dinotefuran (DNF), showcasing its potential in addressing recalcitrant organic pollutants. We reveal that the incorporation of iron atoms in place of tungsten within the electron-rich [WO₄]^2- layers significantly facilitates electron transfer processes and boosts the Fe(II)/Fe(III) cycle efficiency. Complementary experimental investigations and theoretical analyses further elucidate how the atomically dispersed iron induces lattice strain in the Bi₂WO₆ monolayer, thereby modulating the d-band center of iron to improve H₂O₂ adsorption and activation. Our research provides a practical framework for developing advanced photo-Fenton catalysts, which can be used to treat emerging and refractory organic pollutants more effectively.